I have engine temp problem. I have spent the last couple of hours search the UBB, and have gotten some pointers from other post on some things to do. But I wanted to get some opinions on my particular situation. The problem is on my 1983 Z28 195,000 miles, its not my daily driver anymore, but this problem has caused me not to take the car out for fear of damaging her.

Here it goes:

The car started out with a slight "overheating problem" back in November and it was slowly came to the point it is at now by late to early February. I start my car up it runs fine. The temp gauge reads normal. However after 2 miles of driving the temp gauge slowly makes its way up into the dreaded "red zone." Performance doesn't seem to be effect all that much though, if any.

When I stop and pop the hood, it doesn't feel too incredibly hot....? Just kinda warm. It doesn't feel to me like what an overheating car should feel like. Especially, not what the gauge is reading. Nothing is boiling over either. Also, after driving the coolant reservoir has little bubbles in. I have heard this can be a sign of a bad head gasket but there appears to be no oil in with coolant, nor any coolant in the oil. The car is mysteriously loosing coolant, however. Since, car isn't driven much. The coolant level doesn't seem to lower when the car isn't driven and there are no puddles on the garage floor. It only disappears under continual usage.

The air dam is there but is crack directly down the middle. I didn't figure this to be much of a problem since it is a small crack and not a break.

I have thought that the sending to the temp gauge could be bad but, I am kinda skeptical since it takes time for the needle to make its slow decent upwards and the problem as slowly gotten worse within the last few months.

Thanks

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1983 CFI Z-28 305 cid pretty much stock except for CenterLine wheels, Fresh new custom paint job by Dan Butts; torch red black 25th Anv. style stripes, and a few minor performance mods i.e. hollowed out cat, cat back system, Accel Coil, and wires ect. New 350 or 383 in the works! ------------------------------------
New project car:
85 Berlinetta w/ 454 big block. 540+HP
Edlebrock RPM Performer:
aluminum Heads
750 cfm carb
cam & Lifters
intake manifold
timing chain
Crane Energizer Roller Rockers 1.7, Hooker Super Comp. Headers, Custom built TH350 tranny, 2,500 stall converter, B&M Console MegaShifter
Future plans:
paint job, interior re-vamp, custom exhaust.
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Member of COFBA (Central Oklahoma F-body Association)http://www.cofba.com/

 

Overheating like that AND loosing some coolant with everything else you describe is usually a head/gasket leaking coolant into the combustion chamber. Its happened to me 2x. Depending on how bad it is yet you can sometimes tell by starting the car COLD with the radiator cap and look for air bubbles coming up through the coolant. If you have any mechanical ability you can fix it yourself for about $100 ($50 for gaskets + $50 for having heads cleaned and magnafluxed). It can also be an intake gasket but that would be awfully lucky. I have seen it though. It is very labor intensive so if you have to pay someone to do it you are better off to buy a new motor than to invest that much into one with that mileage.

[This message has been edited by brharris27370 (edited July 20, 2001).]

 

It sounds to me like the first thing you should do is replace the gauge's sending unit. Cheap, easy, and since the gauge itself rarely fails that way, will tell you if you actually have an overheating problem or not.

If the gauge is in the red but the car is not pinging and nothing is boiling and there's no other sign of heat stress, the gauge is probably the only thing wrong.

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"So many Mustangs, so little time..."
ICON Motorsports

 

I agree. Start with the basics. Swap out the sender, flush the coolant, replace the t-stat. These are all very inexpensive things that could be your problem. It really doesn't sound like a stuck t-stat but it could be. It could also very easily be the sender just misinforming you as to what the temp is but I rarely see the senders go bad (for the guage anyways). Since replacing the sender and/or the t-stat involves losing some coolant, it is a good opportunity to flush out the coolant. These are fairly simple jobs involving cheap componants as well so you won't be investing a lot of work or $$$ for nothing if it doesn't end up fixing it.

If the cooling system is working correctly (fans come on properly, good t-stat, clean radiator fins, fresh coolant, air dam in place) and the guage is reporting the temp correctly (ie known good sender) and you still are overheating, chances are you have blown a head gasket/warped a head.

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1987 GTA L98 MD8 GH3
355 '97 Vortec 4-bolt block, TRW(suck) forged pistons 10:1 CR, TFS 23*, LT4 Hot Cam, Ported plenum and intake, SLP Siam Runners, Edelbrock TES, gutted Cat, Flowmaster, K+N cone, AFPR, TB bypass, AirFoil, !AIR, !A/C, !EVAP, ARAP, 2300 stall, Hotchkis STB.

 

I agree with the temp guage sender but I would replace the air dam as well. What looks like a crack may be opening up or warping under air flow pressure. Also Desert86Roc made me aware on his Camaro of some A/C Condensor Seals that were missing which seems to be a common problem.

http://www.gmtips.com/3rd-degree/

Enter Site
Choose Tips
Look at the overheating articles and the A/C condensor seal article.

... I would also replace the radiator cap. These are very cheap parts compared to the cost of an engine.