My 1994 chevy cavalier is overheating mainly on hot days and when I work the engine hard. My coolant level hasn’t dropped in a long time and the coolant cap is usually dry. I replaced the thermostat and checked the radiator hoses. They seem to be fine. My engine is leaking coolant (see photo)
right after the thermostat. Any thoughts on this issue? Do I need to flush the system?
Make sure the radiator is full. If you go by the plastic overflow bottle, when coolant is leaking from the engine, that can appear to be ok, but the radiator can still be low.
Overheating on hot days and when working the engine hard (as opposed to when idling, waiting at a fast food drive-thru), first suspects are
- coolant level low in radiator
- radiator cap isn’t holding pressure
- cooling system isn’t holding pressure somewhere besides the cap
- thermostat isn’t working or isn’t opening to the proper dimension
- air in cooling system
- radiator partially clogged
When you replace the thermostat, did you replace the gasket too? Sometimes the thermostat doesn’t come w/a new gasket, b/c the gasket is different for the same thermostat, depending on which make/model/year of car it is being installed in. If you didn’t install a new gasket w/the thermostat, suggest to start there. Also make sure you haven’t accidentally installed the thermostat in backward. Some thermostats have holes in them that have to be oriented in a certain direction too, usually at the top.
I have filled the radiator up to the cap with coolant and it has seemed to run okay when doing that. But once that is used up, the system isn’t pulling more coolant from the reservoir.
I did get the gasket and replaced that as well. I believe it is in the correct way. But I can recheck that.
Is the leak out of the engine something I should be worried about?
You have the pressure cap on the reservoir, correct?
Yes, fix the leak. It might solve all your problems.
Common sense dictates if you have an easy to fix leak, which that one seems to be, fix that first. Leaks can make it impossible for the cooling system to fully pressurize like it should, and that can cause overheating.
That may not be the entire solution, but it is part of it. You might want to just replace the pressure rated cap on the overflow too, as it is probably inexpensive.
I’m looking at that picture, and a few possibilities come to mind
The thermostat housing or gasket is compromised, causing the leak
The head gasket is leaking
Yes, I do. And it holds pressure well. So I don’t think it has to do with that.
What are your recommendations for fixing a leak coming out of the engine itself?
If the head gasket is indeed leaking, then the only thing I recommend is to replace the head gasket
If that turns out to be the case, put a straightedge on the head and make sure it’s still within tolerance. Otherwise,a machine shop will need to “clean it up”
You could hook up a coolant pressure tester . . . you should rapidly see if the leak is the head gasket or the thermostat housing
Might be the head bolts just need to be retorqued
That is really helpful. Thank you!
I will be exploring these things the next day the weather is decent.
Well if its the original radiator, you could be just exceeding the cooling ability of the system now as the radiator has become less efficient over time. If you replaced the cap and the thermostat, it might be time to replace the radiator with a fresh one. Another thing that can make a difference is bugs blocking the fins on the radiator. I’d at least try pressure washing the front of the radiator if you can get at it.
I’m afraid it’s time to take it in to dealer or competent mechanic to consider water pump/et al. replacement which includes a radiator test + flush and SHOULD include changing all the belts in their way and since hoses are cheap, replace all with new (saving both labor & coolant $$$ later on).
I guessed all these answers posted here when looking at an 8x10 of my situation, comparable to your picture. Mystery solved at mechanic = WATER PUMP and more, mostly old, rusted out even though a 2001 and housed well, babied & not driven far every year.
My daughter’s first car was a '95 Cavalier. At 160K miles it was leaking coolant out at the head gasket (the third head gasket on this car). She didn’t want to junk it (sentimental). It was fall (cooler) so I loosened the pressure cap and wired it so it wouldn’t fall off. With no pressure to force coolant out, she easily got through the winter and gave the car away the next year.
WTH . . . ?!
Am I missing something here?
That picture looks like the head gasket may be leaking
And you’re talking about replacing a water pump and radiator
I’m sorry, but that doesn’t make much sense to me
… and it LOOKED exactly like this to me … on mine as well, bub
Sorry if this doesn’t sound nice . . .
But based on that little picture that we have been provided, I’m leaning towards a head gasket
Now if OP were to provide more pictures, which clearly show a radiator and/or water pump leaking, I might have another opinion
But until that happens, I’m staying put
I’ll add one more thing, though . . . a coolant pressure test should quickly point out the leak, beyond a shadow of a doubt, as it’s looks to be more than minor seepage/sweating
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Underneath the thermostat isn’t leaking. From what I’m hearing from everyone I am leaning towards the head gasket.
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I found a video of a cavalier head gasket repair. So I think I might give that a shot considering where the leak is.
Thanks for the added information
Another procedure you could perform is a block test . . . it will let you know if you’ve got combustion gases in the coolant. The head gasket is often the culprit
This is something you could easily do yourself, and the tool price is reasonable.
That is one funky looking gasket on the thermostat housing, Could be thermostat housing gasket leaking.
If you’re going that route, it’s generally a good idea to replace the head bolts. They usually come in a set. Felpro makes decent gasket kits, FWIW
https://www.napaonline.com/napa/en/p/FPBHS9469PT2/FPBHS9469PT2_0233289973
https://www.napaonline.com/napa/en/p/FPBES74016/FPBES74016_0233061891