Overheating Question

My water temp gauge started climbing uncommonly high today; I drove it on the interstate for a few miles for the first time in a few months probably, and after that, my temp went up to about 80 percent toward the H. It usually doesn't climb past half way, 2/3 at most if I'm driving hard.

Well, with some heat on I can at least drive it, and if it gets very close to the H I will certainly pull over. My current plan of attack to solve the problem is as follows:

1) Replace thermostat
2) Replace radiator cap
3) Check radiator fans if the above does not work. Anyone know when they are supposed to come on?

Any more suggestions? I am hoping it is a thermostat problem. Getting a new thermostat is worthwhile anyway, if it is still the original one.

make sure that it is full, check the mixture of coolant, i'v been told that it makes a difference. also dont forget your water pump.

Ona 2g its ont likely to be the fans, but its possible. I would check that first though, just because its so easy. Let the car idle until they kick on. 210 degrees is where you should see the main (pass side) fan come on. On a 1g fan not ocming on is more common, beucase they use a switch on the radiator that often fails. In a 2g the ECU has full control of the fans.

The other two things you mean to try are good steps to take. These things should be changed every so often anyway, so no harm done if it doesnt fix the problem anyway...

well i had that same problem...check all your hoses... i cracked hoses and lost all my coolant... also the thermostat NEEDS to be replaced bc it was overheated and probably no good... also check the water pump... and maybe your radiator needs to be replaced... get a fluidyne and your car will run MUCH cooler... you may wanna have yours checked bc it may have a clog....

dont drive your car... it will just get hotter and hotter.... then you will melt the head like me ! :)

I just put on a new radiator cap and will see if that solves the problem. My coolant resevoir was full to the top (a little bit trickling out past the cap it was so full), so I'm inclined to think it is probably not a leak in a hose or something. I noticed no other leaking coolant under the car. I have my fingers crossed that the radiator cap will do it, but I'll let you all know.

-Question: if I drive the car and keep it from getting too close to the H on the water temp meter, can I still damage it? I mean, should I just lay off the car and run it only to try and fix it until the problem is solved? I do NOT want to melt a piston or blow a headgasket.

well...
dont drive it then... i blew my head and pretty much destroyed the gasket....you know the plastic cover that covers the spark plug wires? i melted that... hehehe dont drive it till you fix the problem

yeah i don't know i tried all those steps before on my car when it was overheating and they all seemed to not fix the problem... what you should do is take out your thermostat and re install everything without the thermostat, then start your engine and let it idle till the fan comes on and the what you should do, be very carefull and remove the cap while the engine is running then rev your car up and then let go of the throttle and see if coolant comes shooting out then i'm sorry but it is your head gasket. what happened to me is that same stuff you were saying, my coolant resivouir tank was always overfilling and my car was always running too hot. i changed the gasket and i havn't had a problem with it since. works awsome!

p.s. you don't have to take the thermostat out if you don't want to it should open up when the fans kick in anyways i just decided that i would take mine out! just be carfull when doing this because of the obvious coolant and steam are very hot! i hope it was something as stupid as the cap for you cuz the gasket is a bitch to do in these cars!
good luck

the other ways to tell if your head gasket is gone is if their is water in your oil, you are burning coolant or not only will coolant come shooting out of your car when hot but their will be air in your coolant lines and it will bubble..

Cap wasn't it, unfortunately. Next on my list is the thermostat, so I will pick up one of those tonight or tomorrow and throw that badboy on. Maybe that will do the trick. I've had no signs of a bad headgasket yet--no water in the oil, no white smoke out of the exhaust, no steam from under the hood. I'm keeping my fingers crossed that it is something simple and easily rectifiable!

do you have a datalogger or some way to track knock? if youve recently done any new mods you might want to undo them and see if it fixes it. because if you get knock it will make your engine temp go up. you could also try turning down the boost and see if that helps. if it does your probably boosting to high and getting knock or you got crappy gas

Nope, no new mods--bone stock under the hood. I have new parts just waiting to be installed, but I am going to wait until I figure out the problem. I noticed that the sparkplug cover was starting to melt around the screws, so I am really going to be careful driving it now--temp goes up more than 80 percent and I am pulling over.

I'd check the radiator. My brother had a similar problem, replaced all the things you're planning on replacing, but still it got worse and worse. His started overheating when summer came on also; turned out that the radiator was about 10% clogged; he replaced it and -boom- (John Madden boom) it went right back to normal temp. Of course he then had all new cooling system parts. :)

ya try flushing the rad really good. i had that problem but it turned out that my overflow tank fell off. i opened the hood and it was gone. cap was there. 27 bucks at the dealership later... :banghead:

also don't have you overflow tank 100% full. i would even dump most if not all of the water out of it and give the rad room to breathe. my bet is on a rad flush though.

i bet its your termostat. same thing happend to me with my first laser. it cost me head gasket. after i fixed the gasket i didn't even bother puttin a new termostat. the same thing with the GST now. one day my temperature started raisin and i just take the termo off. i dunno about u guys, but here's how i catch when my car is starting to go HOT : once the car get to a point where its TOO hot, a loud clicking noise appears. like bad lifter or wherever. i suggest if u hear something like that and have your temp gauge a little over half the midle , shut the car off and let it cool for a while. i personaly would not let my car's temp gauge go over and past the midle of the gauge...even in the hottest day or a few 0-100 mph runs. its just not supposed to.(and u know its getting real hot over here)
finaly i want to add that driving your car constantly hot or a little hotter would cost u your valve oil seals, than the car starts smoking and u wonder and on and on...
thats at least what i know for problems after overheating. hope it helps


p.s.by the way if u need help installing the up's for your car pm me( my sell is off for a lil)

I remember my uncle told me this a while ago.. take the thermostat and put in in a pot of boiling water and it should open. If it does it is working. And measure the temp of the water and then find out what the thermostat should be opening at. Then you will know if it works or not.

I am not sure if that is all or if I left something out.. I just remember bits and pieces.

I have blown the HG several times in a way that there is no smoke, no fluids mixing, no overheating, none of the signs people normally associate with the HG. But when ever I would build boost my overflow would fill up. Most DSMers running high boost in fact will check the overflow after every run at the track ;)

The HG can blow in many many ways. I've broken it all down before in other threads, but the HG seperates several systems. Atmosphere, combustion chamber, oil system, coolant system. It can fail between any two points, and fluids (air is a fluid btw) will move from high pressure to low pressure. So everyone can say "I bet its [insert cuase here]", and might get it right. But there are too many failure modes to be able to say its one thing or another. Same goes for overheating issues. What may have been the cause for one guy, may not be it for another. So its best not to say you know what it is for sure, but to offer one more solution that has worked for your problem in the past.

Thats my friendly public service announcement for this week :D

Thanks to everyone who has responded--I still have not solved the problem. I flushed out my system today and refilled with new fluids, after replacing the radiator cap yesterday. I revved the engine and a friend said a bunch of bubbles came out, so I tried to get rid of the air. Still no luck.

At idle, it doesn't seem like it would overheat. I idled it for 10-15 mins. and the temp gauge was dead on in the center the entire time. I guess the good news is there didn't appear to be oil in the coolant--although I suppose I could still have a hg problem without there being oil in the coolant.

Tomorrow I guess I'll do the new thermostat. If that doesn't work, picked up a shop manual today and will test the water pump via there convoluted method. ANyone know an easy way to do it?

Thanks for the help everyone, I just want to get the car running so I can throw my UICP and bov on it!

It seems like it is the thermostat.

Does the temp stay up or does it come back down a bit, then go back up, down again...?

if its got bubbles in the coolant and probably your head gasket leaking exhaust into your coolant

it would also bubble after you flush your radiator and fill it back up. The bubbles would be comming from traped air in the system working its way out. but if it doesnt stop bubbling than there is a problem.

After a ridiculously long time working in cramped space in the driver's side corner of the engine bay right up against the firewall or radiator, we finally got to the water pump and pulled it. Unfortunately, all of the impellers were intact and there was no shaft play at all.

However, the water pump pulley had started eating into the plastic bottom part of the timing belt cover...there was a deep rut in the shape of the pulley. When we removed the timing belt cover, there was one bolt missing right where the rut formed. The plastic was all scraped to one side, partially melted. The belt was also frayed on the side that touched the timing belt cover.

I hope this solves my overheating problem. I suppose the water pump could work fine at low rpm, but when it had to work harder at high rpm the friction of it against the plastic casing was too hot, overheating my car. This is my best guess anyway. I have no clue where to start if all this work doesn't solve the problem...but I will NOT be happy!

If things are fixed tomorrow, hopefully I can get my UICP, bov, and air filter on!

sound more like the problem was just the 40% clogged radiator with the old pump fins in it.

This would have been my course of action in this case. If the pump looked good inside, do the tbelt since most of the hard labor is done. Once you have the tbelt stuff off for the pump swap, 95% of the work is done for a head gasket change. You would need 60 bucks for a new gasket, and 90 bucks for ARP studs. All you have to do is remove the UICP, and the 4 turbo bolts, and miscellaneous small things (wiring, throttle cable, etc). Pull the head with both manifolds on it. Install the studs, and see my previous posts on how to make sure this HG will last. Then its back to putting the tbelt stuff back on...

I'm still not sold on the HG theory, but it would make sense to change it while most of the work is done. Plus a stock HG and ARP studs will prepare you for up to ~30 psi ;)

Well Kevin didn't get back to me in time for me to take his advice on the head gasket and studs (thanks Kevin!!! lol)...but here's what happened:

We thought it had to be the water pump (a mechanic concurred--he checked the headgasket repeatedly, even did a leakdown test, and maintained that the HG was just fine!). Instead of paying the mechanic $350 to replace it, I decided to do it myself.

After removing everything, including the pump, the impellers were ALL fine. HOWEVER, the lower timing belt plastic cover had a wear mark where the water pump pulley had ground/melted a rut into the plastic. Surely this was my problem, so we sanded down the cover so it wouldn't rub, bolted it down more tightly, and put everything back together--plenty of clearance after we put it back together!

But after everything was back on the car, it won't start. The starting motor turns over rapidly, the timing belt spins, but no noise from the engine (like a piston hitting a valve, etc.). I have spark from the plugs, and I smell fuel, but nothing. Anyone have ideas--ask me for details if necessary!?


[timing belt was removed, and when we retimed it i believe everything was done properly according to the Haynes manual...cam sprockets' marks lined up (no more than 1 tooth off), crank sprocket lined up, timing belt not missing any teeth, good tension, etc...**I didn't see the 2g timing belt guide in the vfaq, so I didn't use the tensioner tool through the rubber plug hole, maybe that could be a problem!?]

Be sure the cam gears marks are line up, AND the dowel pins are at 12 oclock. Aside from that, the only thing that should keep it from starting would be some sensors you forgot to plug back in. The cam and crank sensors are in that area, depending on year.

When you say it turns over rapidly, do you mean faster than normal? Thats usually a sign of low compression. I would do a compression test to be safe before anything else.

Yea, my GST did the same thing too. It was the thermostat. It got so hot it melted the oil off of everything. My mom was so pissed. We used to have the cleanest driveway ever.

Oh yea... It also did it when my dad thought it would be cool not to screw the radiator cap all the way on. Yep... That was the time we got stuck at taco bell with an overheating car, keys locked in, running. It's always fun to share such exciting experiences with your dad.

Haha thanks for the story GSTRacerNVUS! And Kevin, I believe the belt slipped, because we had the timing nearly 180 degrees off btw...DupetoE from our forum was kind enough to come over and help us re-time the engine (and by "help us" I mean we handed him tools while he fixed the car ;))! Thanks SO much Dupe, that was a lifesaver.

Before we got the car running, we decided to compression check the cylinders. First cylinder read 160...second cylinder 30. No, I did not forget the 1...it read 30. The rest of the cylinders all read 30. I was NOT happy. However, we figured the problem could be with the gauge, so I tried to start the car again, and after some pumping of the gas pedal it fired up...and held a healthy idle! It was great!

We checked the timing again and it appears to be right on. However I noticed while I was driving my car back from my buddy's house where we were working on it that it would hesitate when I tried to accelerate a little faster than usual. When I gave it a little more gas it was almost like I upshifted into too high of a gear, and it would hesitate and there would be a very subtle vibration/shuddering from the car. At slow acceleration to normal and even high speeds (I was going almost 60 at some points), it was fine, just as usual. Only during quick acceleration does it hesitate and shudder. Maybe this is just the result of a rich condition after I pumped the pedal a good bit to start the car? I don't know. I hope and pray it isn't a result of the timing being ONE notch off or something, because 5 tries lining the belt up right is enough for me!

**Edit>>DupetoE suggested getting new plug wires, b/c mine are cracking in a few places....could this also be the cause of my hesitation when I accelerate more quickly?

Worst of all....the car is still overheating. Yes, I want to kill myself. No, there was no point to taking off ALL of the parts necessary to look inside the water pump. Damn-it -all. Tomorrow I will remove the thermostat, maybe replace it. Can I just run without it, because Dupeto suggested that would solve the problem?

i'm not too familiar with TS's and DSM's, however i do remember taking out the TS on a couple different cars and solving some summer overheating problems.

Yep... I agree. But it could also be the head gasket. Thank GOD it was just my thermostat. My mom was really pissed off still, cause my car got so hot it melted all the old oil that had accumulated in the engine compartment. We used to have the cleanest driveway on my street... Ooops... Well what was I supposed to do?

Yes... You can run your car without the Thermostat. Actually, when mine went bad and I took the thermostat off, my car ran the best it had ever run before... I almost didn't want to replace the thermostat, but as sensitive as these cars are I didn't want to take the chance and screw something else up.

No TS can cause you coolant temps to be too cool. If they dont stay over about 170, I forget the actual number, the ECU will think the engine is still warming up and will run in "choke" mode... Too rich means weak power. I wouldnt bother. I would find the source of the problem, rather than just bandaid it...

we need to make a book out of kevin's head

'everything you ever need to know about your DSM: Quotes by Kevin'

nah, i'm just going to compile it all up and make my million! don't worry Kevin, i'll split it with ya 50/50 on the profits ;)

The issue I'm most concerned about now is the shuddering problem I'm having...at idle and when I rev it in neutral it is fine, but when I'm driving in gear, anything more than feathering the gas pedal and my car begins shaking like someone learning to drive stick (but not QUITE so severe!), and I BARELY accelerate. I've found that if I get more than 2 mmhg of vac toward boosting, that is usually when the problem occurs, and if I accelerate slowly enough, it seems I can get high in rpms as long as I do it SLOWLY...any theories?

Do you think this could be caused by having timing one tooth off or something? Jake said I should leave the crank sprocket one half tooth before top dead center when timing the engine, but have the cam sprockets perfectly aligned with a straightedge. I'm going to waste a lot more time doing this tomorrow (for the 5th try, 3rd taking all of the other pullies out of the car) unless someone informs me that slightly off timing would not be my problem.

We didn't mess with any other major systems (to my knowledge) that could be causing the shuddering. After I take care of this shuddering and hesitation, I still have my overheating problem to deal with :(