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Discussion Starter · #1 ·
Yesterday afternoon...during rush hour traffic, of course....I noticed my temp gauge slowly moving past the vertical midpoint. I cut the AC and turned on the heat, put it in neutral and revved the engine and the temp dropped back to normal.

On the way home I "played" with the process and verified that it would maintain a normal temp range, when idling in traffic...until I would turn on the AC.

I checked the fan once home to see that it was, in fact spinning (stuck a thin zip tie into the fan's blade path and it was spinning). I didn't feel like it was blowing a ton of air to me (not sure how much air pressure there should be). I could not get the temp gauge to rise over midpoint.

Anyone have any suggestions on things I need to check out? Thermostat didn't act as if it were sticking, fan is working. What next?

Water pump? Everything sounded normal while under the hood.


2006 V50 2.4
226K miles. Was planning on doing another TB/ACC Belt/Water Pump/Tensioner swap in a few weeks once the school year is done.

Thanks.
 

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Fans have gone weak on folks here before. It's possible while the fans are GOOD the system and relays in their control modules might not be good, and therefore is your issue.

I know mine hits about 230*F and it starts blowing like crazy - which is right below when the needle starts to move. Sounds like the control module for your fans (and maybe your fans themselves) are going bad.
 

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Sometimes the fan/control will throw a code if it detects a problem.
 

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Discussion Starter · #4 ·
Thanks for the insight.

Any way to check the modules? Relays? I am not getting any codes.

Also, this morning while waiting in traffic the temp started rising....and a message popped up on the display. I revved the engine a bit while contemplating how to move across traffic to the side of the road....and the temp when back to normal. Popping the car in neutral and revving the engine dropped the temp back down.

So...is the the revving causing the water pump to compensate for the lack of fan power? Is the fan somewhat controlled by engine speed?
 

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It's very unlikely to be the water pump, unless you see actual debris in the coolant reservoir. If the impeller vanes were ground down to that point, trust me you'd see something.

It's more likely that it's the radiator fan. Revving the engine will also increase the flow through the heater core, and that can take out a significant amount of heat in anything but the hottest weather. And the fact that it doesn't appear to happen "on the road", it's clearly related to depending on the front fan. "Spinning" is not enough, it's a very powerful flow in normal operation.
 

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Discussion Starter · #6 ·
It's very unlikely to be the water pump, unless you see actual debris in the coolant reservoir. If the impeller vanes were ground down to that point, trust me you'd see something.

It's more likely that it's the radiator fan. Revving the engine will also increase the flow through the heater core, and that can take out a significant amount of heat in anything but the hottest weather. And the fact that it doesn't appear to happen "on the road", it's clearly related to depending on the front fan. "Spinning" is not enough, it's a very powerful flow in normal operation.
Thanks for that.

I was thinking it was probably the fan with the spinning it was doing, but not pushing as much air as I thought it should....but hoping not....looks like a bear to get out....gonna be a long Saturday.
 

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You should really try to test it first - it's not impossible there's another cause, or something else is contributing. Have you verified that the ECT is reading accurately? This requires VIDA and a thermometer.
 

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Discussion Starter · #8 ·
You should really try to test it first - it's not impossible there's another cause, or something else is contributing. Have you verified that the ECT is reading accurately? This requires VIDA and a thermometer.
I used an infared thermometer to check temp increase...and the increase was there.
 

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Thanks for that.

I was thinking it was probably the fan with the spinning it was doing, but not pushing as much air as I thought it should....but hoping not....looks like a bear to get out....gonna be a long Saturday.
Absolutely not a bear for us - undo the powerplug and then lift up and pull towards the engine. Super easy. Airbox removal is the bear.
 

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I used an infared thermometer to check temp increase...and the increase was there.
I totally believe the increase, what I was wondering is whether it's sensed by the engine control. If, say, the ECT reads 175 when the coolant is actually at 200, well, the fan won't be commanded to full-on when it rises.
 

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Discussion Starter · #12 ·
swapped the temp sensor and thermostat as well as a complete coolant flush and fill.

All seems to be good after 2 weeks.

Thanks for all the help guys.
 
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