Engine temperature running hotter than usual

[FLUX @88]

a major benefit of vacuum filling is eliminating most if not all trapped air

[82DMC12]

Thanks everyone. I've been busy lately but had a bit of time to keep working on this overheating (?) problem last night. I have now installed a ball valve in the thermostat self-bleeder line so I can bleed it off but then stop it so I'm not constantly bypassing hot coolant to the reserve tank. Last night I double-checked the alternator/water pump belt and tightened it up just a bit more. I also idled the car and waited until the thermostat opened. Then I opened the ball valve long enough to get the bleeder hose good and hot (telling me coolant is running through and not air) before closing it again. I did this twice while the car idled for about half an hour. During this time the fans kicked on just past 160F mark, and they would run for about ten minutes before cycling off. The fans cycled on/off twice so at idle anyway I seem to be maintaining good cooling.

This weekend I should have time for a test drive so I'll see how that goes - maybe I still had air stuck near the thermostat?? Or maybe the continuous self-bleeding just wasn't getting the air out.

PXL_20220523_000127211.jpg

[David T]

When you are driving (and not running the A/C) the fans won't always run because when the car is moving, air is moving through the radiator so the cooling system doesn't need the fans unless it is very hot. That is normal, just watch the temp gauge.

[82DMC12]

When you are driving (and not running the A/C) the fans won't always run because when the car is moving, air is moving through the radiator so the cooling system doesn't need the fans unless it is very hot. That is normal, just watch the temp gauge.

Right. My problem before was the temp kept rising up to nearly 220F and wasn't falling even if I was driving at 55 MPH. If I can drive it for 30 minutes and the temp stays closer to 160F like it always used to (and fans cycle on/off if standing still at idle long enough) I'm going to call it good! Previously, the car would idle , hit 160F and the fans would come on, but they never shut off because it seemed like they weren't cooling enough. I'm glad to see they were cycling now and the gauge was hovering just above 160F in the meantime.

[bytes311]

Purely anecdotal, but my fans kick on around the 160F mark and generally run for a couple of minutes. 10 minutes seems like a long time at idle to cycle off?

[David T]

There are some variables like ambient temperature and every "O" switch is a little bit different. As long as the temp doesn't get over 220 F (and even that is variable, the temperature gauges are not known for accuracy). Make sure the fans are not shutting off because the circuit breaker popped and resets.

[82DMC12]

Purely anecdotal, but my fans kick on around the 160F mark and generally run for a couple of minutes. 10 minutes seems like a long time at idle to cycle off?

I'll probably come back to this thread a bit later as I'm working on a couple other small issues right now, but seems like NOW my fans come on just above 160F and the temp kind of runs between 160F and 180F (a bit higher when A/C is on) but the fans aren't cooling it enough to cycle off again very often. I haven't had much time to test it but I drove it for about 30 minutes and let it idle in my garage for a while and the temp was just kind of stuck right about 165F and the fans didn't stop after 15 minutes.

At this point I don't seem to be close to overheating anymore so I need to work on a couple other issues before I return to this. Thanks everyone for the help so far and I'll check in again later.

[ssdelorean]

Well here is what I learned today.

<<snip>>

It wasn't until I backed out and started driving that the temp started to climb, especially once I hit about 55 mph for a few minutes. Then the temp comes up to 215F and won't come back down even back at idle.

Any great ideas on what to check next?

Possible cogged heater core or radiator? <<snip>>

I was thinking a possible radiator clog or at least a restrictive flow than what normally is suppose to happen. Your mention of not happening until driving the car is what got me to think that. I had a slightly similar issue where my temp would go up at highway speeds (AC on or off, didn't matter) but driving at slow 25mph or idle speeds would be fine. Ended up being a clogged radiator.

[Bitsyncmaster]

You want the fans to kick on above the thermostat opening temp. You would also want the fans to turn off a little below the turn on temp. If you have the fans go on to low then they will run all the time your hot engine is running. But with most of us running AC all the time the fans run all the time anyway.