I'll try to be concise.
89 4wd is overheating. I have done work on it including
TPS
Flush Coolant
new wires plugs cap air filter but none of that applies to this
On the Maiden Voyage I was going up to the mountains, it was in the high 80's- low 90's. About half way up I saw the needle creep to 3/4 line, I pulled over and idled for a bit and it brought the temp back down once up into the cooler climate the temp stayed fine.
Once I got the O/D working I loaded up for vacation, A kayak on the roof and another inside with me. It was 105, and I climbed up a pretty steep mountain, the temp went up to a bit above 3/4 on the way up but coasting down it went back to normal. When I got off the freeway and on the street everytime I would stop it would creep up and continue up. Eventually it got pretty high and I pulled over and when I shut it off it boiled out of the over flow a whole mess of liquid. Once it quit over flowing I filled it back up with water, got on the freeway and made the rest of the 80 miles no problem even having to do stop and go traffic for a bit.
Then down in San Diego on one hot day in traffic I got the temp gauge going up and it wouldn't go back down by idling. When I pulled up to our house it lost a bit of coolant from the over flow, but not the whole thing. Added more water and it was cool for the rest of the trip.
Then on the way home I had two kayaks on the roof and it was at night about 82 or so. I saw the temp go up over hills and drop back down a bit on the other side but 80 miles into the trip I was running a bit less than 3/4 and I pulled over and it went red when I got to the parking lot. I shut it off and it over flowed A LOT. I had dinner then filled it back up with A LOT of water and made it home no over heating issues.
I figured I must have blown the head gasket with a small leak and it was loosing water through the overflow and eventually it would just boil over. So after hearing how much a HG replacement would cost me I ordered a test kit online. While waiting for it to ship I found an amazing deal on a JDM import 3Y with only 30,000 original miles. It was such a good price and I was so sure it was the head gasket I snatched the engine up.
I get the tester in the mail and I just did it (Letting the engine warm up to operating temp) Hooked it up to the radiator cap and bubbled air through the liquid and it never turned yellow! I had it hooked up for about two minutes and it stayed blue the whole time until after a bit it sucked in some of the radiator fluid, but two minutes is what it said to leave it hooked up for and it stayed blue the whole time.
So what could it be, Fan Clutch or Radiator right? Fan clutch feels the same resistance as the one on my JDM engine so I think it's alright. How would I check the radiator? any ideas? thanks!