Overheats w/ac on

Hello all,
I have a '95 Blazer. I have been through the entire cooling system. New water pump,thermostat,rad. cap,fan clutch and radiator flush. The only thing that we haven't done is completly remove the radiator and and spray out the fins, we did spray the best we could from the inside out. It does have the tranny and engine oil coolers in the same stock radiator. The condenser coil is also in front of the stock radiator in its stock location.

4.3 vortec
Automatic
4x4

Thanks,Jay

When you say overheat does it get all the way up in the red, or just run hotter than normal? Also what is the normal running temp with the AC off?

Sounds like you have some air in the system.

Remove the stat and take a ride to get all of the air out of the system.

JEREMY -
runs way hotter then it ever did around 230
Normal Opporating Temp is around 190

Your fan clutch might not be engaging all the way.

Go out when the engine is dead cold and try to turn the fan by hand.

This one is really odd. All I can think of aside from the fan clutch not working properly is that maybe the bearing in the AC compressor are somewhat seized and causing more of a load on the engine.

This one is really odd. All I can think of aside from the fan clutch not working properly is that maybe the bearing in the AC compressor are somewhat seized and causing more of a load on the engine.

load on the engine should not cause overheating with a properly cooled engine.

Jeremy- After doing more checking found out a/c clutch isn't disingaging and did a relay check. The three relays on firewall seemed to be working. Are there any others I should be looking for? Thanks, Jay

First remove the top of the fan shroud, four or six little bolts down on the sides, then lift off. Look between the radiator and the condensor, not at all unusual for this area to fill up with leaves, grass, trash, believe it or not. Then I'd sure suspect the fan clutch, when the engine is this hot, the fan should be roaring very loud, hard to miss the sound.

hi, I don't mean to hijack your thread or anything, I have a similar problem and figured this would be a good place to post my question since the topic is similar and the cars are similar as well.

My girl has a 1995 GMC Jimmy SLE. She has only had it for a few months. I've noticed when in stop-n-go driving with the A/C on, the car tends to get warm. (a few small lines past the the big middle line) But it doesn't get warm when doing constant freeway driving. As long as the A/C isn't on, the cars temp only goes up to a line or two before the big middle line. The time it got the hottest was on a 90+ deg day in stop-n-go driving. It almost got to the 3/4 mark. Has never gotten into the red though. When taking off from the light, I could hear the fan roaring and then as the temps would drop and the fan would quite.

I haven't done anything to the car yet because I don't want to just throw money at it. I've done some reading on this site over the last couple days and have some ideas of what it could be but don't really know what to look for to see if those parts are bad. For example, someone wrote to try spinning the fan with the engine cold. If it does spin what does that mean? If it doesn't, what does that mean? Sorry if thats a stupid question.

Sorry if this is not enough info, I don't know what else to add Iif I forgot some info that would help in figuring out the problem, please let me know and I'll do my best to get that info. I'm new to SUV's and domestic cars, I'm used to working on my Honda so things are a bit different but I'm learning.

Any help would be greatly appreciated.

Thanks

I was experiencing something similar when my machine started to leak and the fluid in the radiator core got low. She would overheat slightly at idle (225 degrees) though would remain cool at highway or side-street rolling speeds. Check your radiator fluid level when she is dead cold, like sitting for at least 4 hours or overnight. Do not rely on the overflow bottle at all in this case, but what you can see (or cannot see) when you look under the radiator cap. Top her off with a 50/50 mix of coolant to distilled water, then turn the truck over. Let it idle until hot and the thermostat opens. Refiill any fluid that is "lost" when air bubbles out of the system with the engine still running - top it off to the radiator filler neck, and pop the cap back on. Refill the overflow tank to the hot/full mark and let it run a bit longer so the system presurizes.

Inspect for leaks or smell of coolant, fluid dripping on the ground, fluid around the end tanks of the radiator, hoses and heater lines. Shut her off and let it sit, continuing your inspection at the points above. Check for greasy, humid spots around the defrost vent and the windshield glass just above it in the cab, and of course, look for anything leaking on the ground. Check your oil level too - elevated levels could indicate an internal leak that's dropping coolant into your crankcase. I just had this happen to me from a combination of heater core hoses that were shot in the engine compartment, and lower, leaking manifold gaskets.

ok, I haven't taken the rad cap off yet. I'll have to do that and check the level.

There is no drips on the ground or anything and I don't see any signs of coolant leak in the bay. The bay looks dry.

Is there a proceedure on making sure all the air bubbles are out of the system? For example, on my Honda's I've had a little bleeder valve on the thermostat case that I would loosen and connect a hose to. Run the car and when the fluid coming into the hose becomes a constant stream of coolant I know the air bubbles are out of the system. Is there anything like this for these cars?

Thanks for the reply thus far, please keep them coming.

Yep, just do what I described above. Start the engine with the rad cap off and idle until hot and thermostat opens and fluid starts moving. Top it up to the top of the neck of the radiator cap and put the cap back on and then refill the overflow tank. For the next week, watch and refill the tank as the air bubbles come out through the tank and then draws more fluid back in through the overflow.

I just had a quick question concerning this air conditioning thing. I have a 1998 Blazer, and live in central Florida, where it has been hitting 100 degrees a few days out of the week. I never drive with my air conditioner on because I am afraid it is bad for my car and will cause it to get too hot. Does this make any sense? Is it bad to run a vehicles air conditioning? I just don't like putting too much stress on my engine. Also, how long is too long to let a vehicle idle say in a parking spot waiting for someone with the air? I baby my truck, possibly too much, and just wanted to know how irrational I am being. Thanks.

No harm will come from running the A/C at all. All it does in the long run is consume a little more fuel because it scavanges a little power away from the engine to run it. It will never overheat running the A/C unless your cooling system is in a horible state of no maintenance. Idling for more than 3 minutes is not recommended unless it can be avoided. If you idle the engine for prolonged periods of time (more than 25 minutes regularly) I would change your engine oil according to your severe use schedule in the manual. Idling also does not allow for full oil circulation, possibly in the long term experiencing bearing wear in the journals and races furthest away from the oil pump. So in short, if you are going to sit in place for more than 5 minutes, best to shut her off and head inside to shelter. :) Believe it or not, NOT running your A/C is more harmful that running it. If it sits for a prolonged period of time without use, oils in the refrigerant do not circulate, lending itself to damaged/dry rotted seals.

Thanks a lot. I figured I may be acting a little bit too cautious, but I just wanted to make sure. I always figured idling was bad for a car especially if you are just waiting for someone to say come out of the grocery store and just sit there for 10 minutes in 100 degree weather with the A/C on. Thanks, now I won't have to sweat profusely anymore haha. Damn its hot here....

ok, I checked the level in the radiator and the over flow. The radiator was a little low and the over flow was basically empty. So I filled the radiator and ran the car until the thermostat opened and then topped it off. I let it run a bit longer and then turned the car off and filled the over flow to the hot line.

We took the car out for a spin with the A/C on max and it got just a touch higher than normal (one small line below 210). once it hit 210 and then dropped back down. It was around 8:45pm so it was only about 80 outside with the sun down. I'm going to take it to work tomorrow and hopefully get to test it in the heat of the day in rush hour traffic.

One thing I did notice is when the A/C gets turned on, the tensioner trembles a bit. But as soon as you turn the A/C off, the tensioner and belt runs smooth again. I don't know if this is a sign of the tensioner going bad or if it's supposed to do this. Is there a spec for how tight the belt is supposed to be? Where do I measure this spec at? I assume that if the belt is a bit loose that could mean the tensioner is going bad?

Any input would be greatly appreciated.

Thanks

Tensioner automatically holds the belt at the proper spec. A little wiggling and wobbling when the A/C is on is normal. It's when you hear it knocking as it *flops* about that there is a problem with it and it needs replacement. Look at the top of the tensioner with the engine off. You will see a set of marks and an arrow on the tensioner arm that will rest somewhere between the marks. There are two indentations followed by a longer flat "land". The arrow should be at rest anywhere between the two lines and the flat land. As the belt wears, it stretches. When the arrow goes past the end of the land, time to change the belt. That, or - just change the belt every 30~35K miles. Easy to do it yourself. :D

Now watch your coolant in the overflow and check the radiator by looking into the filler neck diligently, over the next few days. You may want to have a mechanic, or you may wish to borrow a pressure tester to perform a leak-down test. Putting a magic marker dot on your oil's dipstick before you do this will help spot internal leaks. But once pressurized, a cold engine will easily be inspected for external leaks in the cooling system. If no leaks are apparent, leave it overnight with the cooling system pressurized. If it has lost pressure over that time, pull your dipstick and look at where the oil level is in comparison to the dot you left on the stick. You may have to chase an internal leak if there is no visible coolant on the ground if the system leaks-down, and your oil level rises.

I always figured idling was bad for a car especially if you are just waiting for someone to say come out of the grocery store and just sit there for 10 minutes in 100 degree weather with the A/C on.

Idling in a properly maintained vehicle will never bring it to harm. She will make a good solid roaring when you first take off though - chances are the fan's gonna dump any heat you may have built up while sitting there. What's going to eat your lunch unless you keep up with oil changes is the sheer torture idling does to engine oil. If oil's left in the crankcase too much longer than the 3-5K mile "Severe Service" schedule in the truck's manual *and* polonged idling is your game - time to start thinking of how long ago you had the filter and oil swapped out. You may also benefit from switching to a synthetic as it's more robustly featured against this sort of punishment, but I would not run longer than 6-7.5K miles in your situation. Consider too, swinging away from 5w-30 engine oil. A good stout 10w-30 all year round in Florida is MORE than adequate. And since the split between winter "pumpability" (the 5w part) and the oil's main weight (the 30 part) is smaller, it will be a bit more durable to high temp, prolonged idling situations. Basically, less "stuff" that they use to concoct the full body of the oil is used that can be depleted. Idling and high temps depletes the additives and starts to break the oil down quickly into nasty, gummy stuff. The less "additives" used to fortify and "build" an oil to a specification, the more durable it seems to prove to be. I will not go into the specifics, but this should give you a good bit of insight into my logic on this matter. I personally use 1 quart of Shell Rotella 15w-40 Full synthetic to 3.5 quarts of Shell Rotella 10w-30 dino or "fossil" oil to get a slightly heavy 30 weight in the crankcase. In the winter, straight dino Rotella 10w-30 goes in. I change it every 5k Miles and it always comes out pretty damn clean. (Rotella's a "mixed fleet" Heavy Duty Engine Oil (HDEO) though primarily for diesel motors, does exceptional things in gas engines too) I choose it for it's insane qualities of bearing up to short trips, winter idles to get the feet toasty before take-off and it's cleaning qualities. Once I finish the next change of HDEO in the crank case, she's going over to a diet of full synthetic. I am hearing great things about Mobil-1 Extended Performance, and it has some exceptional qualities on par with the Rotella but - in a clean, well-tuned engine, would be a once a year fill up. (But I would still change my filter every 5k~7.5k Miles and top off with half a quart of more Mobil-1 that's lost in the filter body)

Damn its hot here....

Yep, and I would have been down there enjoying it, seeing my family if my truck's cooling system didn't decide to...well, forget that it was supposed to hold liquid. My mom's telling me how wretched it is out there, especially since her A/C broke down in the Minivan. I just got through charging and balancing my A/C in the Blazer - it's going to be over 100 degrees here for the next 3~4 days!

hi, I don't mean to hijack your thread or anything, I have a similar problem and figured this would be a good place to post my question since the topic is similar and the cars are similar as well.

My girl has a 1995 GMC Jimmy SLE. She has only had it for a few months. I've noticed when in stop-n-go driving with the A/C on, the car tends to get warm. (a few small lines past the the big middle line) But it doesn't get warm when doing constant freeway driving. As long as the A/C isn't on, the cars temp only goes up to a line or two before the big middle line. The time it got the hottest was on a 90+ deg day in stop-n-go driving. It almost got to the 3/4 mark. Has never gotten into the red though. When taking off from the light, I could hear the fan roaring and then as the temps would drop and the fan would quite.

I haven't done anything to the car yet because I don't want to just throw money at it. I've done some reading on this site over the last couple days and have some ideas of what it could be but don't really know what to look for to see if those parts are bad. For example, someone wrote to try spinning the fan with the engine cold. If it does spin what does that mean? If it doesn't, what does that mean? Sorry if thats a stupid question.

Sorry if this is not enough info, I don't know what else to add Iif I forgot some info that would help in figuring out the problem, please let me know and I'll do my best to get that info. I'm new to SUV's and domestic cars, I'm used to working on my Honda so things are a bit different but I'm learning.

Any help would be greatly appreciated.

Thanks I had the same problem with my 97 changed the clutch fan. Problem solved if the truck seems to be better or ok on the highway or when your moving along and then gets hot when you stop change the clutch fan.

ok, thanks.

I saw those marks on the top of the tensioner but I wasn't sure if thats what they are for. I don't remember where the arrow is in relation to the marks but I do have the car with me today at work (it's going to be a hot/humid day today, should see if adding the coolant helped at all)and I'll go look when I go on break. I know the belt and tensioner are an easy fix, I replaced one on my moms Explorer a few weeks ago because her tensioner just popped one day when she was leaving work. It looks even easier on the Jimmy than it was on the Explorer.

So basically I should check the fluid level on the overflow and the radiator while the engine is cold, before I start it up each day? Should I fill it up at the filler neck if it is low or should I just watch the overflow to go down and then add to the overflow?

By pressure testing, are you refering to something like the pressure tester you can rent at AutoZone? I've never done it before but I'm sure I can figure it out.

Thanks

I had the same problem with my 97 changed the clutch fan. Problem solved if the truck seems to be better or ok on the highway or when your moving along and then gets hot when you stop change the clutch fan.

clutch fan

edit:
ok, nevermind. Found the answer to my question. Not hard to replace.

So thats why someone said earlier to spin the fan with the engine off. I didn't understand until now. From what I read, if there is no drag and spins more than 5 times when spun by hand then replace it. Or if it cannot be spun or has a rough feel then replace it. Is this correct?

I did try spinning the fan before and it felt smooth with some resistance. I didn't know what I was looking for though. So now that I do, I'll take a look at that during my break when I look at the marks on the tensioner.

Thanks

also, I read in multiple threads on here to look for blockages in the radiator by feeling for cool spots on the radiator. I couldn't figure out how I was going to do this. So when I was waiting for the car to warm up yesterday, check the level of the radiator fluid, I looked at how I could test for cool spots.

I think if I just remove the fan shroud I can get to a lot of the rear side of the radiator with a temp probe. (with the motor off of course)

Do you think this is a good way of looking for cool spots, meaning blockages in the radiator? Also, do you think blockages in the radiator could be causing the problem I'm having or will I just be wasting my time doing this?

Thanks

clutch fan

edit:
ok, nevermind. Found the answer to my question. Not hard to replace.

So thats why someone said earlier to spin the fan with the engine off. I didn't understand until now. From what I read, if there is no drag and spins more than 5 times when spun by hand then replace it. Or if it cannot be spun or has a rough feel then replace it. Is this correct?

I did try spinning the fan before and it felt smooth with some resistance. I didn't know what I was looking for though. So now that I do, I'll take a look at that during my break when I look at the marks on the tensioner.

Thanks Does it seem to run cooler on the highway and the temp rise rapidly ehen you stop.

umm...I wouldn't say rapidly but it does rise. Then once I start moving again, even just a little, it starts to cool down a little.

Is there anything else other than what I listed above to look for to see if the clutch fan is indead bad. I mean, what your saying makes sence, I just want to be sure and not waste money.

Thanks

ok, I just went outside on my break and looked at the position of the tensioner and how the fan feels when you spin it.

The tensioner arrow is just to the right of the "v" notch. So that means the belt should be ok, correct?

I spun the fan, it felt smooth. Had some resistance. When I tried to spin it to see how many times it would rotate, it spun about 1/2 a revolution or so. It didn't have any play (wobble) in it either.

Any input would be appreciated. Thanks

umm...I wouldn't say rapidly but it does rise. Then once I start moving again, even just a little, it starts to cool down a little.

Is there anything else other than what I listed above to look for to see if the clutch fan is indead bad. I mean, what your saying makes sence, I just want to be sure and not waste money.

Thanks Its bad its not engauging enough to remove the heat from the radiator. Same exact symptom and it worked in mine thats why the temp drops when you start to move more air is gettin thru.

ok, I understand what your saying. It's just that I want some sort of test to know for sure that the clutch fan is bad, not just the symptoms.

Thanks

ok, I just went outside on my break and looked at the position of the tensioner and how the fan feels when you spin it.

The tensioner arrow is just to the right of the "v" notch. So that means the belt should be ok, correct?

Well, it's okay as far as stretching is concerned. Inspect belts for glazing, cracks, or seperation of the various plies that make it up. On the v-groove side, make sure that the grooves are all evenly worn, and there are no chunks missing out of the little ribs. The tensioner indicator is only for stretching/tension and will not be a visual indicator of "Good" and "Bad" - just how much life you have left to the belt's size if it's not cracking and falling apart. They stretch as they wear but if the belt's falling apart, replace it immediately, regardless of what the tensioner "life monitor" says.

I spun the fan, it felt smooth. Had some resistance. When I tried to spin it to see how many times it would rotate, it spun about 1/2 a revolution or so. It didn't have any play (wobble) in it either.

Any input would be appreciated. Thanks

I think you may have indeed just found your problem. Fan clutch is bad. The fan should turn smoothly with *firm* resistance. Grabbing at it and trying to give it a spin should not see it rotate like you describe. I am with the other folks here in that you may have indeed found your culprit. The only test that I am aware of involved using a refrigeration/food prep thermometer, a power drill, duct tape and a peice of cardboard.

Using the cardboard, you partially restrict the front grille to indudce a quick heat up. Turning on your A/C to MAX and high fan aids the quick warm up. The drill is used to poke a hole in the shroud between the fan and the back of the radiator into which one sticks the thermometor. Hold the thermometor in place securely with a strip of duct tape over one corner of it's face so it does not accidentally get sucked into the fan. The probe should be in the air flow, and if the clutch is good, you will hear the fan engage and spin up to engine speed at about 180-190 degrees. Remove the cardboard and let the engine idle until it cools itself off. The roaring should cease when your thermometor reads below 180 degrees.

the belt looks a bit shiney on the smooth side. Don't know if that would consitute as being glazed or not? I'll have to remove the belt and take a good look at the grooves.

As for the fan clutch... It does have firm resistance, don't know if it's the right amount or not though. Even just a half revolution is bad? hmm, ok. I guess I might just take the chance and buy the fan clutch then. Does $64 for one sound like a good price or too much?

What do you think about my idea for checking for blockages in the radiator? Or do you think I would be wasting my time with the radiator and should just go to the fan clutch?

Thanks for all the replies. I don't mean be a pest, I just want to make sure thats all. Thanks again.

Mine's a little shiney too, as it tends to wear smooth on the idler and tentioner pulleys. If it's worn through or hard caked (glazed) it will make chirping/squeaky noises as the engine turned. THe only way I know to check for "cool spots" is with a spot-reading infra-red thermometor immeditely after the engine was stopped after warming up, or through the front grille. Either way, to have that diagnosed would cost more than the clutch. Make sure you do not buy a "heavy duty" clutch by mistake, thinking it would work. Just get an OEM, standard clutch. I can get them through NAPA and Autozone for a little more than $50. (Heavy Duty clutches cost a bit more - but also require a fan with a much more agressive "rake" of the blades.) It is definitely not enough resistance. Grasping a fan blade and turning it hard and fast as I can, it stops the instant my fingers leave the blade. As stated before, it should be firm and smooth, firm enough to stop the fan blades from spinning instantly when you turn it fast by hand. So try the clutch swap. It will be cheaper than having someone with a thermal gun "shooting" the front of your radiator.

ok, so it should stop as soon as my fingers leave the blades. That helps, I thought it shoudl probably spin a little. OK sounds good. Thanks for the tip on the heavy duty clutch. I might just go to NAPA and get it since she wants to get the oil cooler lines as well and that the only place I've seen that carries the entire thing and not just the rubber middle hoses.

Thanks again for the help. I might go pick that stuff up today and give it shot. We'll see. I'll let you know how it goes.

Thanks

A few tips on getting the clutch off:

1)Leave the belt on. It will provide enough tension to spin the nuts off of the face of the pulley that holds the fan and clutch to the water pump. Tapping with a hammer will break them loose. Reassembly can be done by again, tapping lightly with a hammer to snug the nuts.
2) Naturally, the fan shroud will have to come off. There are bolts all around the shroud and on the sides, midway down the sides of the fan housing. Getting those out can be done with an extenstion about 12" long.
3) Removing the intake plumbing will be needed to done before you reach anything else in there easily.
4) There will be four bolts on the back of the fan that hold the fan to the clutch. If they are hard to tun, again using a hammer to tap your wrench the right way can help. I have not known them to sieze on anything I have worked on before, but they can be hard to turn at first.
5)On '97 or later models, there is a large nut that holds the fan and clutch assembly on the water pump pulley. Holding the pulley stationary, one can use a rented fan/clutch removal tool that is basically a huge cheater bar with a chuck on the other end that futs the nut. I hearsay from others that the "Ford" fan clutch removal tool works, but I would always check for size and snug fit before starting the job.

All said and done, you could be in and out within an hour, and I am a total monkey when it comes to doing stuff like this. :)

ok, thanks for the tips. I probably would have removed the belt to innspect it when I was doing this. Now I know I'll either remove the belt and inspect and reinstall before doing the clutch or remove and inspect the belt after.

Take a magic marker to mark which position the belt was in before complete removal. Putting a belt back in backwards from the position it was put in originally acellerates wear and failure. I should have made that tip #6. :D I usually just put an arrow mark on it indicating which side faced the engine.

oh, ok. I didn't know that, thanks.

I looked at the fan again and it seemed looser when I went to leave from work. When I checked it during my break, the car had only been sitting for about 3hrs. When I left work it had been sitting for about 8.5 hrs. I spun it and it seemed to rotate a little more than earlier. So I went to my moms (she has an Explorer) and felt how her fan resistance felt in comparison. Hers had a firm smooth feel, the Jimmy had a smooth feel with a little resistance but not nearly as firm as my moms. I know it's not the same car but I figured it should give me somewhat of an idea of how the fan should feel. I also spun it and it didn't spin nearly as much as the Jimmy did.

I also looked at the belt again and it doesn't look glazed. I will take it off and check the inside grooves to be sure. But I did buy the fan clutch from AutoZone for 63.99 because NAPA wanted 82.99. I will be doing the oil cooler lines, oil change and the fan clutch tomorrow after work. So hopefully Saturday the car will be running nice a cool, should be high 80's on Saturday so it should be a good test.

I'll let you know how it goes.

Thanks

well, yesterday my girls brother and I replaced the oil cooler lines and the fan clutch.

The fan clutch was pretty simple and straight forward. Didn't take much time at all.

The oil cooler lines weren't that bad either. Once the driver side motor mount bolt was removed and the motor was lifted just slightly to gain access to the rear part of the oil cooler lines, a couple long extensions and a flex joint was able to easiley remove the bolt holding the rear part of the oil cooler lines.

Then today we took the car out for a spin to test the A/C overheating problem and the car did great. Never hit the 210 mark, always stayed below it. Today was almost 90 but the humidity wasn't bad. Thanks for all the help in diagnosing the problem. Now I see why the fan clutch was bad. Once I had the new one in the car and bolted down I tried to spin it. It pretty much stopped as soon as my fingers left the blade.

We also went to my moms boyfriends work and they welded the fornt sway bar mount back onto the lower A arm. Then we bolted the sway bar back up and was on our way. The welds that held it on broke and the endlinks were rusted so bad everything was seized together and had to be cut apart.

So all in all... today was a good day. No more oil leak, no more over heating and the car rides much better with the sway bar mount fixed.

Thanks again

GLad to hear of your success! Good luck and may you get many miles out of your "new" truck. :D