Over heating question - Toyota Nation Forum : Toyota Car and Truck Forums

KRB64 · 01-30-2011, 02:10 PM

I have an '89 Corolla auto with 140,XXX. All of the sudden it started overheating the same time the radiator rotted out. Got real hot, real quick one time. New radiator but now it boils still. Fans work. Water pump must otherwise why would the radiator boil right?

I pressure tested the head and cylinder #1 = 200psi, #2 = 165psi, #3 = 175psi & #4 = 200 psi.

Could a blown head gasket cause the overheating or did the overheating warp the head and blow the gasket?

No oil in anti-freeze but I believe there is anti-freeze in the oil.

I can replace the head gasket but want to make sure there is not an underlying cause that I'm over looking.

Thanks,

***plyr503*** · 01-30-2011, 07:38 PM

you checked/changed the thermostat correct?

KRB64 · 01-31-2011, 05:03 AM

No. I figured if it was stuck open then it wouldn't over heat and if it was stuck closed the radiator wouldn't ne boiling over. That not correct thinking?

Flashmn · 01-31-2011, 06:41 AM

Quote:

Could a blown head gasket cause the overheating or did the overheating warp the head and blow the gasket?

Thats very possible.

Quote:

Water pump must otherwise why would the radiator boil right?

Not necessarily, the water will boil in the whole system and if the water isnt circulated it will boil quite easily as cool water isnt pulled in.

***plyr503*** · 01-31-2011, 06:46 PM

Quote:

Originally Posted by KRB64

No. I figured if it was stuck open then it wouldn't over heat and if it was stuck closed the radiator wouldn't ne boiling over. That not correct thinking?

Actually that makes sense, thermostats are just so cheap that when I overheat I generally swap it out first thing and pray...

KRB64 · 02-01-2011, 05:17 AM

Quote:

Originally Posted by plyr503

...thermostats are just so cheap that when I overheat I generally swap it out first thing and pray...

True, I'm just never that lucky...

corolliaxe · 02-01-2011, 02:15 PM

The thermostat is pretty cheap. I believe I put a stant brand name thermostat that came to less that 4 bux. When I changed my radiator I changed the hoses and the thermostat. It wasn't really that much more and you get peace of mind knowing that's not going to be an issue any time soon. I would just go ahead and changed the thermostat and see how that goes.

It shouldn't cost you any anti-freeze either because you can always recycle that.

So my suggestion is that since it can’t really hurt to replace the thermostat, just do it and pray it’s not the head gasket.

KRB64 · 02-02-2011, 05:54 AM

Good point but with the 25-35psi discrepancy between cylinders I'm afraid my head gasket is already toast...

90 GP · 02-02-2011, 06:01 AM

I would guess the head gasket is toast too. Hope the head didn't get warped. These engines don't seem to tolerate overheating.