Victor Vaughn

I just changed timing belt, water pump and thermostat with OEM new.

I've noticed when my car is idling at stop it will start to get hot. The temp gauge won't hit the red, but it will come about 1cm from the red line. Whereas when I'm driving the needle will stay left of center gauge, much cooler.

Isn't it also supposed to stay at the same temp more or less when I'm stopped as when I'm driving? Outside temp is 107-109 F

idling at stop after 15min

driving on highway

jfrahm

See if the viscous fan is a lot harder to turn by hand after the engine is hot (engine off) than cold.
There is also the "magazine test" where you see if you can stop the fan from turning with a rolled-up magazine, it's a bit rude.

Victor Vaughn

So the viscous fan does seem to be harder to turn by hand after the engine is at temperature, rather than cold. But I wouldn't say "a lot." It just seems a bit harder. It's pretty stiff either way hot or cold. It's a brand new duralast fan clutch. I replaced it 3 weeks ago.

Thanks a lot for your help by the way.

Hey...what about the Auxiliary fan?? Could this be the problem? Could mine be weak or bad? How can you tell? But mine seems to spin freely and there doesn't appear to be any strange noises or bearing play in it.

jfrahm

Is it blasting away when idling with the AC on?

d2noob

That's your mistake buying neverlast junk from AZ! I use to work in a repair shop and they mainly used parts from AZ and they seems to always have problems and the customer would come back because the neverlast parts fail so it gets warrantied out or buy from a different auto parts store supplier. It's best to buy OEM parts as your likely to have less issues with it later down the road.

jfrahm

Recently got stuck waiting for a flagger and saw my temp gauge go about as high as yours idling with the AC on. Only 90F outside at the time.

A8 Ronin

Aside from this specific situation, have you ever seen your gauge cross over into the second half? I've had two accounts recently (during 90+ degree days) where my gauge has crossed over the normal operating range, and it was with the A/C on (level 2 fan speed) during idle. I haven't noticed, nor intentionally attempted to let my car idle without the A/C on in order to find out if it will still overheat. If I do test it within the next couple of days, I'll report back my findings.

hillpc

I also support investigating the airflow (fans). Going down the highway the motion of the vehicle pushes air through the radiator.

jfrahm

I have not noticed in the A8, have not really looked. My other cars run up to 3/4 in traffic with the AC blasting so I'd seem pretty normal. I will check the S8 one of these days.

A8 Ronin

I sat in a parking lot for 32 minutes idling (without the A/C) and the gauge didn't budge even a millimeter. Some aspect relating to the A/C being on has to be the culprit.