Overheating - Toyota Nation Forum : Toyota Car and Truck Forums

C110GTR · 09-07-2009, 07:19 AM

Got the head gasket done recently and the car is still overheating.
Thermostat doesnt seem to be opening top hose hot, and bottom hose cold to feel. So replaced it with a brand new one, check the flow of radiator, bottom hose/pipe and still overheating just from driving around the block.

Took the thermostat off and run the engine and its circulating fine.
so bought another aftermarket thermostat same brand and model installed that temp gauge stayed 1/3 drove around the block overheated straight away.

Any ideas what could be causing this?

car is a 1993 3VZFE V6 auto

Camry LE 94 · 09-07-2009, 08:49 AM

how is your coolant? does it need to be flushed or has it been flushed recently? also the water pump could be going...

C110GTR · 09-08-2009, 02:04 AM

well the water pump got replaced today, radiator was 50% blocked
I'll see tomorrow when everything's put back together if that solves the problem

Jimnist · 09-08-2009, 04:48 AM

Could you have maybe put the head gasket on the wrong way, blocking the water channels?

Or was it overheating before?

C110GTR · 09-08-2009, 05:07 AM

nah was having overheating issue before the head gasket, thats why it blew the gasket

TheKevin · 09-09-2009, 12:02 AM

were the heads resurfaced when you replaced the HG?

C110GTR · 09-09-2009, 06:05 AM

yes and was just recently tested and passed C02 so no leakage there

Jimnist · 09-09-2009, 07:10 AM

So is everything sweet since you put the new rad in or is it still running hot?

C110GTR · 09-10-2009, 05:06 AM

the culprit was the thermostat, we bought 2 new replacement one same brand and both not opening at the right temp.
what temp should the thermostat starts to open up?

whip_cracker · 09-10-2009, 10:56 PM

Ah so it WAS THE THEMOSTAT! Mate, like I said on Auscam once before, always use OEM thermostats... that goes for water pumps too.

C110GTR · 09-18-2009, 06:50 AM

4 thermostat later and still same issue
last thermostat was a genuine toyota item and it seems to be restricting the flow and overheats.

install a gutted thermostat and she runs fine.

anyone have any idea

bill buttermore · 09-18-2009, 07:24 AM

Quote:

Originally Posted by C110GTR

4 thermostat later and still same issue
last thermostat was a genuine toyota item and it seems to be restricting the flow and overheats.

install a gutted thermostat and she runs fine.

anyone have any idea

As others have mentioned, have you replaced the water pump and/or the radiator? It is also possible after draining the cooling system to create a large air void in the engine upon re-filling that can lead to overheating. But that usually happens only on the first fire-up after re-fill. I like to fill the engine through the top radiator hose first, and then fill the radiator and the overflow tank. If trapped air is not the problem, considering that you have changed the thermostat four times, I vote for a bad water pump or rad. Water pumps can fail without leaking - the impeller can become loosened on the shaft and slip preventing the proper circulation of coolant. Don't let the engine get too hot or you will be doing that head gasket again!

If you have a new head gasket, new water pump, new radiator, new thermostat, and no air voids, the only other reason for overheating that I can imagine is that you have a blockage to coolant flow somewhere in the system. You should be able to determine this by reverse flushing the engine and the radiator.

Edit: There are a couple of other possibilities that you will not want to hear - cracked head or cracked block. Those often result in exhaust gases entering the cooling system and causing coolant to bubble in the overflow tank - but not always. The way to test for these major problems is with a cooling system pressure test. Did you pressure test the head when you replaced the head gasket?

C110GTR · 09-18-2009, 07:29 PM

the head was cracked tested and was skimmed for straightness

new water pump, radiator professionally clean as it was 50% blocked

Im pretty sure theres no trapped air

bill buttermore · 09-18-2009, 08:17 PM

Quote:

Originally Posted by C110GTR

the head was cracked tested and was skimmed for straightness

new water pump, radiator professionally clean as it was 50% blocked

Im pretty sure theres no trapped air

Well, the only ideas I could offer at this point are to reverse flush the engine to ensure there are no blockages. And, I suppose you have changed the lower radiator hose. It could collapse at higher rpm if soft, restricting flow to the engine.