Overheats w/ac on

[TRKDRVR]

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

[Jeremy Fitch]

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?

[BlazerLT]

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.

[TRKDRVR]

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

[BlazerLT]

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.

[Jeremy Fitch]

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.

[BlazerLT]

Originally Posted by Jeremy Fitch

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.

[TRKDRVR]

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

[tom3]

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.

[95GMCJimmySLE]

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

[wolfox]

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.

[95GMCJimmySLE]

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.

[wolfox]

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.

[SComp23]

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.

[wolfox]

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.