Guys, I replaced my radiator, water pump, thermostat (195°), and thermostat housing today, and now either my temp gage is lying to me, or my engine won’t reach normal temperature. It’s running cold. My fan clutch is locked, has been since I got it.
I noticed weeping from somewhere up there, so I bought a water pump. Before installing the pump, I decided to flush the system. What came out of my coolant system was mud. Brown, with lots of goo chunks and slime. So I flushed it 3 more times, and it wouldn’t clear up much at all. Under the cap, the radiator looked bad. Lots of silty rust-colored sediment. So I decided to replace it, too. I was going to replace the coolant temp sensor, too, but the auto parts store gave me the wrong part, so I put the old sensor back in. Before I put it in, I noticed that the end of it was covered in silty residue, so I lightly hit it with a scotch brite pad and shined it up a little before re-installing it. I then filled the system with distilled water because I want to flush it at least once more to see what comes out before filling with coolant. I started the vehicle to burp the system, and it would never reach normal temp while idling. I listened closely to see if the engine seemed to be distressed, then I realized that I have no idea what that would sound like, so I stopped. I observed the exhaust, it doesn’t seem to be burning anything it shouldn’t. I had the heater on at idle, it got warm for a moment, then got cool. I took it for a short drive, and the temp still wouldn’t reach normal, but the heater started blowing warm again. Not exactly hot, though. I took some pictures, that was at a stoplight. It actually got ever so slightly cooler when at speed. When I got home, I could rest my hand on the valve cover, it was not too hot. The radiator cap was cool to the touch on top. Inside the cab, the gauge was very consistent during my drive, and didn’t randomly fluctuate. I checked for leaks, there seem to be none so far.
My fan clutch is locked on. I did the spin test when warm and cold, and it’s the same either way, it won’t spin much, not even 1/4 of a turn after I let go. I understand that having the fan on all the time will lower the temp, but that much? I’ll get a new fan clutch as soon as I can, but it’s going to have to wait. I ensured that the thermostat I put in was a 195°.
Any advice? I’m going to try burping it again tomorrow morning to see if I can get any air out of the line, and I’m also going to go get the correct coolant temp sensor and install it.
What part controls the temp gauge in the instrument cluster? Is it the coolant temp sensor? Do you think I got a bad thermostat? Could air in the system be causing this? What I’ve read led me to believe that air in the system would cause spikes, not cold. Is there any chance that this problem will magically correct itself over the next few days? I really don’t relish the idea of tearing it back down.
You may remember from a couple of other threads I posted recently that this is all new to me. I have absolutely no mechanical skill, and probably have low mechanical aptitude. I'm not going to lie, I bought this old Jeep specifically to learn how to work on a vehicle because my friends on Facebook post about their restorations frequently, and it looked fun and rewarding. But, after the investment, I must admit that tinkering with critical systems like this is anxiety inducing. I could use some advice please.
I used this guide for the install, as well as numerous YouTube videos:
https://www.stu-offroad.com/engine/05pump/waterpump-1.htmhttps://www.stu-offroad.com/engine/05pump/waterpump-1.htm
Thanks guys.
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