Replaced HG, still overheating???
 

Hey guys,

I just buttoned up my head gasket replacement for my 87 turbo. I used the toyota head gasket kit with everything from the head gasket up. I also did the timing belt/tensioner/and new water pump. I also ordered new seals for the turbo oil and water lines. In addition, I replaced the clutch fan, radiator, thermostat, and all coolant hoses etc with a silicone hose kit.

I started her up and she runs fine. Keeps good idle, maintains a normal operating temperature. I jump in and drive around the block and the temp guage shoots all the way up, we are talking less than a mile.

My lower radiator hose is very warm, which tells me my thermostat opened. The top hose is hot and has lots of pressure in it when I squeeze it.

What am I missing????

FYI: Heater blows hot and no gurgling sound either...which I did have before I replaced the head gasket.

may have a trapped air bubble, let it sit, cool off and top off the fluids. also check the fan clutch.

Fan clutch is replaced, brand new unit. I will try to top it off and see if it bubbles at all. I am at a total loss here. Going to test my thermostat as well(which is new also).

Hmm See what happens after removing air from the cooling system. Perhaps a wonky temperature sender is causing this?

Any increase in the level of the coolant expansion tank level when this happens ?

Bill I will check. I am working on the car this weekend, I remember how much was in there before it overheated, so I will see if there was any overflow.

What are you thinking?

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?

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....:dunno:

Have you checked your ignition timing recently?

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.

Have you started by testing the thermostat and sensor?

Also, check the exhaust for blockages.

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...:offwall:

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

yea, stick to Napa or the dealer.