It also does that in defrost.

The fan should turn on, no A/C, at about 219F then run until about 180F (the temp the t-stat closes). Continuously if the A/C compressor is on. There may be a different AlGoreithm for turning the A/C off.

The computer should not be checking at startup; as far as I know, there is no feedback for the cooling fan.

 

Hey, DB, whattup?
Maybe the whooshing sound I hear at turning the key on or right after I turn it off is the fuel pump or something? Not the fan, I mean.
I was very happy that it worked fine after unhooking the negative cable.. woohoo, said I.
I sure do love this strange little 4 cylinder car. I get all worried when something ain't just right. Never cared about my old Merc' very much.

 

I reckon the last test I should do is take it for a spin with the A/C on, turn it off (no defrost or recirc) and see if the fan stops as it should.

 

I found out that once the A/C has been on, the fan runs until you turn of the ignition whether the A/c is on or off. I left it on five minutes, turned it off, turned the blower off and the fan still ran.

Shut off the car, waited a few minutes, coolant at 180, started the car- no fan.
This may be normal operation, I have no idea.
Not a big problem, just a weirdness. A quirk.

 

Now that you mention it, that has happened to me before too, fan didnt shut off right away after AC use.

 

It makes sense if you figure if it's hot enough to run the A/C the driver would probably turn it back on or the radiator could probably use the help keeping things cool. It might be programmed that way. Then again I only take short rides so maybe after a while it would have stopped. ?
It is so impressive how the system keeps the coolant between 178 and 181 indefinitely with that fan running, in city driving on my old used car.

 

GM has even used fan delay relays that would control the fan - even when off. Would not surprise me if they have fan controls based on criteria or thresholds on an HHR. A/C would be easy enough for them to use.

 

There is a temp that makes the fan stay on after the engine is turned off. Something like 240F.

Yeah 240F, I been reading stuff that switches between C and F lately, so 140 didn't look that low.

 

Don you mean 240 right? And, my fan almost always stays on after I cut the compressor off at least for a minute or two. I think the fan wont shut off until the car reaches a desired temp; like it runs on the same parameters that are in place when it turns on in traffic to cool the engine down

 

Florida is hot.. The car runs hot in stop and go traffic. I have gotten a good result and lower my temp faster by taking off all plastic guards covering the L and R side and top of radiator.. I know they probably direct fan air flow but results are positive.. Im also on the fence about running dex cool.. I personally like distilled water whereas its less viscous and gives up heat fast.. Please advise?