Replaced HG, still overheating???

Wileyk24 · 10-07-2012, 08:00 PM

Ok so no change in the radiator fluid level. The overflow bottle dipped slightly, less than an inch. The car is not overflowing coolant onto the ground either.

So today I decided to test the thermostat. I took it out, checked the bottom an it is a 195 degree tstat. I proceeded to boil it and with a thermometer found it wasn't opening until well after 200 degrees. Brand new unit, not functioning properly. So I went to autozone to get a new one and the system said I needed a 180 degree stat. So I bought it and took it home and boiled it. The new one open as it should and seemed to open easier than the last. Time to install.

I installed the new tstat, topped off all fluids and took her for a test drive. Good news, I made it a lot further than just one block. I actually drove all around town and on the highway. The car felt good, but my temperature gauge is settling at 3/4 the way up the temp gauge and staying there. Regardless of how I am driving.

So when the car is idling the temp gauge stays right in the middle. Once I start driving city or highway it goes up to 3/4 and stays there. Once it is up there it won't come down until I shut off the car, even at stop signs it stays up there. But once the car is off, I turn the key back on so the gauges are powered and the temp gauge sits at slightly under halfway which is perfect...

Anybody experience this before?

Wileyk24 · 10-10-2012, 01:00 AM

Still at a loss here. Went ahead and ordered new oem thermostat and temperature sensor from Toyota. Even though I had brand new autozone stuff in there already. Apparently if I can buy a thermostat brand new and have it not work, its possible the temp guage is acting up too.

I will replace both and post back my results. Still very open to ideas....

cre · 10-10-2012, 04:13 AM

Have you checked your ignition timing recently?

Wileyk24 · 10-10-2012, 07:39 PM

Yes. First thing I did. Spot on at 10 degrees BTDC, I used a paperclip to short the computer as well. I am putting in the toyota temp sensor and toyota thermostat tonight. Will post back.

cre · 10-10-2012, 08:50 PM

Have you started by testing the thermostat and sensor?

Also, check the exhaust for blockages.

Wileyk24 · 10-11-2012, 03:47 PM

So, I suspected my Thermostat and coolant temp sender that I bought from Autozone were no good. I have seen several posts on this forum saying their products can be problematic, even when brand new. So being fed up and wanting this project finished, I went over to toyota and bought brand new OEM thermostat and coolant temperature sensor. I popped them in last night and sure enough, the car runs perfectly!!! The last two weeks have been hell b/c I thought my car was overheating even after replacing the HG and everything else in-between(Radiator/hoses/Cap/etc). I went through 2 autozone thermostats and 1 autozone temperature sensor. All brand new in box items, all 3 didn't work for $hit.

Sure am going to look at autozone differently going forward. The cost savings wasn't worth the time wasted trying to figure the problem out.

So happy to have this car back on the road...

Sonyps307 · 10-11-2012, 06:02 PM

I don't even waste my time with autozone I went throw 2 fan clutches. Then finally going with a 2 row rad with dual fans. Also went throw a few alternaters from autozone got a 140amp from driftmotion now. I stick with pep boys, Toyota dealer or trusted web sites

10-07-2012, 08:00 PM	#1
Wileyk24 Stock Join Date: Dec 2011 Location: Middletown, NY Posts: 27	Ok so no change in the radiator fluid level. The overflow bottle dipped slightly, less than an inch. The car is not overflowing coolant onto the ground either. So today I decided to test the thermostat. I took it out, checked the bottom an it is a 195 degree tstat. I proceeded to boil it and with a thermometer found it wasn't opening until well after 200 degrees. Brand new unit, not functioning properly. So I went to autozone to get a new one and the system said I needed a 180 degree stat. So I bought it and took it home and boiled it. The new one open as it should and seemed to open easier than the last. Time to install. I installed the new tstat, topped off all fluids and took her for a test drive. Good news, I made it a lot further than just one block. I actually drove all around town and on the highway. The car felt good, but my temperature gauge is settling at 3/4 the way up the temp gauge and staying there. Regardless of how I am driving. So when the car is idling the temp gauge stays right in the middle. Once I start driving city or highway it goes up to 3/4 and stays there. Once it is up there it won't come down until I shut off the car, even at stop signs it stays up there. But once the car is off, I turn the key back on so the gauges are powered and the temp gauge sits at slightly under halfway which is perfect... Anybody experience this before? Last edited by Wileyk24; 10-07-2012 at 08:04 PM.

10-10-2012, 04:13 AM	#3
cre Toyota Racing Development Join Date: Apr 2007 Posts: 5,038	Have you checked your ignition timing recently? __________________ If something breaks or you need to contact a member of the administration please post HERE. Unless it's a private or administration matter please post it on the forum. It benefits no one else if car related questions aren't posted for future users and takes away from the time I'm able to spend helping on the rest of the forum. If you're so inclined I'm always more than happy to accept tips via PayPal. Tip Jar --->

10-10-2012, 08:50 PM	#5
cre Toyota Racing Development Join Date: Apr 2007 Posts: 5,038	Have you started by testing the thermostat and sensor? Also, check the exhaust for blockages. __________________ If something breaks or you need to contact a member of the administration please post HERE. Unless it's a private or administration matter please post it on the forum. It benefits no one else if car related questions aren't posted for future users and takes away from the time I'm able to spend helping on the rest of the forum. If you're so inclined I'm always more than happy to accept tips via PayPal. Tip Jar --->

10-11-2012, 03:47 PM	#6
Wileyk24 Stock Join Date: Dec 2011 Location: Middletown, NY Posts: 27	Successful Head Gasket Replacement Finally!!! So, I suspected my Thermostat and coolant temp sender that I bought from Autozone were no good. I have seen several posts on this forum saying their products can be problematic, even when brand new. So being fed up and wanting this project finished, I went over to toyota and bought brand new OEM thermostat and coolant temperature sensor. I popped them in last night and sure enough, the car runs perfectly!!! The last two weeks have been hell b/c I thought my car was overheating even after replacing the HG and everything else in-between(Radiator/hoses/Cap/etc). I went through 2 autozone thermostats and 1 autozone temperature sensor. All brand new in box items, all 3 didn't work for $hit. Sure am going to look at autozone differently going forward. The cost savings wasn't worth the time wasted trying to figure the problem out. So happy to have this car back on the road...

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10-10-2012, 01:00 AM	#2
Wileyk24 Stock Join Date: Dec 2011 Location: Middletown, NY Posts: 27	Still at a loss here. Went ahead and ordered new oem thermostat and temperature sensor from Toyota. Even though I had brand new autozone stuff in there already. Apparently if I can buy a thermostat brand new and have it not work, its possible the temp guage is acting up too. I will replace both and post back my results. Still very open to ideas....

10-10-2012, 07:39 PM	#4
Wileyk24 Stock Join Date: Dec 2011 Location: Middletown, NY Posts: 27	Yes. First thing I did. Spot on at 10 degrees BTDC, I used a paperclip to short the computer as well. I am putting in the toyota temp sensor and toyota thermostat tonight. Will post back.

10-11-2012, 06:02 PM	#7
Sonyps307 Lexus & 550's Join Date: May 2010 Location: Baltimore Posts: 526	I don't even waste my time with autozone I went throw 2 fan clutches. Then finally going with a 2 row rad with dual fans. Also went throw a few alternaters from autozone got a 140amp from driftmotion now. I stick with pep boys, Toyota dealer or trusted web sites