89fourunner

I am new to this site and I know how helpful it can be. I have an 89 4runner which recently hasnt been running too good. It has 103,000 original miles on a 22R-E. The first six months I owned it, the temp gauge would sit around a quarter of an inch above the cold line. Now, whenever I start and drive the truck, the temp gauge goes up to about half way for a minute and then drops down. After this started happening, I noticed I had water in my oil. So I did some research and found that it was the timing chain cover. Now I solved that problem. Within the last two weeks, I have been trying to solve the overheating problem. I replaced the head gasket, timing chain and tensioners, timing chain cover, oil pump, water pump, fairly new radiator, hoses, thermostat, rocker arms, cam, and a few other things. If someone could please help me, I got stuck in a parking lot last night because it overheated and I need a daily driver.
Thanks

DC.Woods

Maybe you got a bunk thermostat? I'd test it. It sure seems like you have most of the other bases covered! Good luck

Shawn6string

check your oil again and see if your headasket made a good seal. Also the fairly new radiator could be stopped up,( maybe should have invested in a new one). let it warm up and see if your fan is working properly, may be the fan clutch. As it starts to warm up (not overheat) pop the radiator cap and see if the coolant is flowing like it should.

89fourunner

The oil is fine. I have checked it numerous times and there is no signs of water. As for the radiator, I did buy a brand new one. By fairly new, I meant it is a few months old. I can check to make sure the fan is working right and I can also check the flow in the radiator. I am also looking into the timing because it may be wrong from having the head apart.

Evil.Dingo

Your heater core output line empties right behind the T-stat so the coolant temp at this location has been siphoned of its heat from the heater core. Now your t-stat doesn't open until the coolant temp gets hot enough aprox 180 degrees (while the T-stat is waiting for the coolant temp to rise, your temp gauge is rising. Then when it opens, the temp gauge drops and fluctuates between 1/2 and 1/4 way marker due to the opening and closing of T-stat) What you need is below, take the part number, go to Toyota, wait a day for the special order and install. Your truck will run at the 1/4 marker again. I ahd the same exact problem. I got the truck in the spring, no need for heater to be on. As soon as winter came it started happening. Dual stage T-stat fixed it right up.



Toyota P/N: 90916-03070

89fourunner

I adjusted the timing and took it for a spin to let it get to operating temp. It doesnt seem to be doing it anymore, but if it does, I am definately going to go to the dealership to get that thermostat. I really appreciate everyones help and will let you know what happens.
Thanks