overheating, only after shutting off

[e30user]

Temps are stable while the car is on. On warmer days (80+ degree weather), I'll see my temp gauge climb all the way to the red after I park, turn the car off, and turn on the accessory so that the temp gauge is on. If I turn the car back on, things will gradually cool down to normal. The cause is obviously due to the cooling system/flow turning off when the car is shut down, but it still doesn't seem normal to me that the residual heat is causing it to go all the way to the red.

One thing I'm going to try is to hook up the coolant temp sensor for the auxiliary fan an 'always on' source instead of the accessory so that it runs even after shutting the car off until cool. I'm not sure if this will take up too much battery power. I guess I can also pop the hood up for a few minutes after parking. I know our motors are taking up a lot more space so there's probably a lot more heat that needs to dissipate. Still, this seems like a bit much. I was just wondering if anyone else is dealing with this.

[dashboardmonkey]

Going out on a limb here, did you bleed your cooling system?

[e30user]

I flushed the coolant about 5 months ago, which was when I bled it. After initial topping offs, the coolant remained at normal levels throughout the months as expected. I guess there's a chance that there's still some air in it, but I'm thinking that problems with air in the system would also show up if not more so while the car is running. I'm not completely sure about that though.

[surebimmer]

Redline Water Wetter. Add it and see if problem sloved.

[evil_twin]

Thermostat and water pump is good?

[BigD]

Sounds pretty normal to me, esp if it's hot where you are now, or you drive it hard. It's called heatsoak and it's why you always do a cooldown lap after a session on the track - your radiator isn't doing anything if the coolant isn't being pumped through it and the block, which is done by the waterpump. Having the fan run won't do anything either because that just cools the radiator, not the engine - unless you have it set up as a puller, then it'll blow some air on the block too, but that's not too useful either.

[MDryVur]

why don't you get an external thermostat and connect a electric fan on there? just my 2 cents...

[e30user]

Thermostat and water pump is good?

Yea, those things seem fine. I can sit at idle in traffic on hot days at a stable temp.


BigD - I think you're right about the heatsoak. It's what another friend suggested as well. It just surprises me that it gets to such a high level. Although, I was told that this isn't really harmful since it's just the water temp getting overheated and not the motor overheating which would be a different story if the water was getting that hot while the motor was running. It's been this way for a couple years now and I have yet to see any symptoms of a damaged head gasket. I'm still going to check that the temp sensors are all working properly since I haven't really seen others reporting similar behavior.

[Rsully70sev]

Yes I'm bumping a three year old thread lol. I've searched and searched and can't find any concrete solutions to this problem, it doesn't seem to be a common one either.

My S50 runs perfectly while in motion, temperature is solid in traffic, stopped, driving hard, idling, etc. however I'm noticing the same symptoms OP described. Once I turn off the car, my temperature sensor seems to climb a little bit. I've monitored it the past few days, shutting the car off and turning it to auxiliary; the good part is- it doesn't reach anywhere near the red zone at any time, or even the 3/4 mark.

When the car is running the needle sits slightly to the left of the middle mark. When I shut it off and turn it to auxiliary, it climbs slightly to the right of the middle mark. It's a very minor increase, almost negligible, but it bothers me. I'd rather catch a small problem early than deal with a big one later.

Basically what I've gathered is:
-Thermostat doesn't seem to be the problem, it works normally during operation.
-Start with a coolant flush, maybe air in the system?
-Fan clutch seems a little weak (newspaper test) but that would effect the temp while driving, not sitting.
-Water pump maybe?

Any suggestions or experience with this would be greatly appreciated. Also, is it the motors temperature climbing when it's turned off or the water temp like OP suggested? I obviously don't want to cause any harm or damage to my motor.

[7pilot]

Yes I'm bumping a three year old thread lol. I've searched and searched and can't find any concrete solutions to this problem, it doesn't seem to be a common one either.

My S50 runs perfectly while in motion, temperature is solid in traffic, stopped, driving hard, idling, etc. however I'm noticing the same symptoms OP described. Once I turn off the car, my temperature sensor seems to climb a little bit. I've monitored it the past few days, shutting the car off and turning it to auxiliary; the good part is- it doesn't reach anywhere near the red zone at any time, or even the 3/4 mark.

When the car is running the needle sits slightly to the left of the middle mark. When I shut it off and turn it to auxiliary, it climbs slightly to the right of the middle mark. It's a very minor increase, almost negligible, but it bothers me. I'd rather catch a small problem early than deal with a big one later.

Basically what I've gathered is:
-Thermostat doesn't seem to be the problem, it works normally during operation.
-Start with a coolant flush, maybe air in the system?
-Fan clutch seems a little weak (newspaper test) but that would effect the temp while driving, not sitting.
-Water pump maybe?

Any suggestions or experience with this would be greatly appreciated. Also, is it the motors temperature climbing when it's turned off or the water temp like OP suggested? I obviously don't want to cause any harm or damage to my motor.

This is normal.
There is no coolant circulation once the engine is off.
An electric water pump like the Craig-Davies or a small aux electric waterpump as used on the VW VR6 with power after the ignition off could be plumbed in to eliminate the heat soak.

m

[mrcheezle19]

Just like 7pilot said this is completely normal. Once the engine is off coolant circulation has stopped so the temp will rise slightly.