Okay here is the scoop, : 1985 4rnr, 22re, 4wd

Two weeks ago while in Anza Borrego my truck began to over heat. I pulled over and inspected the engine (I didn't check the upper radiator hose for warmth...I know...I was a dumb a55 at the moment) and let it cool. Started back up made it out of the badlands, Started to heat up again, stopped, inspected, and then I drove all the way home and for two weeks, no problem.

Well it started to over heat again on sunday so I started with flushing the cooling system and while doing this It started to heat up again so I checked the upper hose and bingo, cold as a frozen nail. Thermostat problem...bought a new one, installed it, and blam oh.....truck still overheats.

It over heats differently now though. Before when the temp would rise, it would do it after I had already been driving. Now the temp rises right away, and continues to do so while driving. When I pull over though the temp gauge stops at about 3/4 of the way and after a minute or so, drops back to normal. The upper hose is cold while the temp gauge is rising.

I pulled the thermostat I installed and put it in boiling water to see if it was defective but it works like a charm....

Other possibly relevant data:
1. My heater does not work for reasons I have yet to investigate, but it has been this way since I bought the 4rnr a year ago.

2. I ran radiator stop leak before I replace the thermostat to cure a leak near my drain plug.

Here is the thermostat I installed


I'm buggered on this one, any advise?

 

i think the stop leak might be your answer...

 

I would recomend pulling your radiator and having it checked at your local radiator shop. as for your heater not working, try back flushing the heater core with a garden hose, they can plug up and back flushing can sometimes break the sediment and crap loose and get your heater working again. also make sure the heater valve is working.

 

You could possibly have a bubble in the system. Turn the heater on and let it warm up to operating temperature with the radiator cap off. Make sure the heater control valve works and is open so you do not get a bubble in the heater core. It will warm up and if there is a bubble then the coolant will drop in the radiator. Fill it up and let it warm up again.

 

Well, why I didn't do this right away...I don't know Ran the truck this weekend until it got warm and then took of the radiator cap. Upper hose was cold and looking down into the radiator I could see there was no flow. When I rev the engine I got showered. Radiator fluid came outta the radiator like old faithful and hit my exposed fan...... I wish I had a camera so I could take a picture and show you guys what I looked like.....eyes burned for a while.

Anyways, I'm doing a compression test to confirm my belief I have either blown a head or the head gasket. Either way I think it's time to tear the engine to the block and rebuild. I know it's a dramatic response for the problem but I was planning on rebuilding it anyways in the near future. Figure if I do this much work now, I might as well take it all the way. Thankfully public transit is good here in S.D. and I move into a place with a garage and basement with work benches at the end of the month.

I'll keep yall updated.


p.s. Replacing my timing chain was the most advanced thing I have done yet as far as engine work, so rebuilding the engine = a barrage of questions will by flying in the direction of this forum. And yes, I will use the search function before I make any posts.

 

Safety glasses help...

 

What about the water pump? I don't know that the symptoms fit, but its a Hell of a lot cheaper than an engine rebuild.

Or, just replace the head gasket. Are you REALLY ready to rebuild the engine?

 

I have one on it's way from LCE. The water pump would help explain the over heating, but I don't think the water pump could cause the displacement that blew about half a gallon coolant out of my radiator. I didn't get to check my compression tonight, so I will hit it after work tomorrow.

 

You might check this out

http://www.4crawler.com/4x4/CheapTri...tml#Thermostat

 

Find and fix the problem before you dump time and $$ to rebuild the motor. You don't want to fry the newly rebuilt motor during the break-in process over a half plugged radiator or a faulty fan clutch. Also, get a 2 stage thermostat from toyota to cover your a$$. See why here:



http://www.4crawler.com/4x4/CheapTri...tml#Thermostat