Engine running hot...
Pro
Joined: Oct 2007
Posts: 592
Likes: 2
From: Oegstgeest, the Netherlands
I recently replaced the left (front) radiator assembly after a blown fuse and a burnt-out fan motor.
A fairly easy DIY. Found cheap new parts on fleabay (comes with the thermistor):
http://cgi.ebay.com/ebaymotors/ws/eB...K%3AMEWNX%3AIT
In current hot Houston weather I am also running the hack to keep the fans running at high speed:
http://www.ppbb.com/phorum/read.php?6,1509504,1509504
A fairly easy DIY. Found cheap new parts on fleabay (comes with the thermistor):
http://cgi.ebay.com/ebaymotors/ws/eB...K%3AMEWNX%3AIT
In current hot Houston weather I am also running the hack to keep the fans running at high speed:
http://www.ppbb.com/phorum/read.php?6,1509504,1509504
Burning Brakes
Joined: Dec 2006
Posts: 1,211
Likes: 67
From: Pensacola, FL
[QUOTE=SSST;8691730]My radiator fans have been running all Summer long. Maybe not at highway speeds (I can't hear them on or off at speed), but certainly while the car is sitting in traffic. Temp guage hasn't gone much above 180, so I'm not sure 212 degrees is what triggers them. I guess my guage could be off, but it's pretty consistent at hovering around 180 regardless of the ambient temps or speed of the car.
The fans come on at low speed whenever the A/C is switched on. That's why you're hearing them before your temp gets to 212 degrees.
The fans come on at low speed whenever the A/C is switched on. That's why you're hearing them before your temp gets to 212 degrees.
Race Director
Joined: Sep 2006
Posts: 19,031
Likes: 266
From: Bentonville, AR
[quote=Down South;8691967]
Correct. And my observation is this helps to keep the coolant temp more stable and lower than it would be otherwise.
On a mild day, mid 70's, and in stop/go driving I have observed (and data logged this) my Boxster's coolant temp climbing to the point the fans come on. The fans run and the coolant temp drops and then the fans shut off the process repeats.
Even in warmer temps though with the A/C on the fans of course run all the time with the result the coolant temp stays relative stable and way under 212F. By 'way under' under highest I've seen it get (save that time in AZ) is about 205F.
Sincerely,
Macster.
My radiator fans have been running all Summer long. Maybe not at highway speeds (I can't hear them on or off at speed), but certainly while the car is sitting in traffic. Temp guage hasn't gone much above 180, so I'm not sure 212 degrees is what triggers them. I guess my guage could be off, but it's pretty consistent at hovering around 180 regardless of the ambient temps or speed of the car.
The fans come on at low speed whenever the A/C is switched on. That's why you're hearing them before your temp gets to 212 degrees.
The fans come on at low speed whenever the A/C is switched on. That's why you're hearing them before your temp gets to 212 degrees.
On a mild day, mid 70's, and in stop/go driving I have observed (and data logged this) my Boxster's coolant temp climbing to the point the fans come on. The fans run and the coolant temp drops and then the fans shut off the process repeats.
Even in warmer temps though with the A/C on the fans of course run all the time with the result the coolant temp stays relative stable and way under 212F. By 'way under' under highest I've seen it get (save that time in AZ) is about 205F.
Sincerely,
Macster.
Thread Starter
Rocky Mountain High
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Joined: Aug 2007
Posts: 19,500
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From: Kolorado
Well, it's already at the mechanic. I'll keep you all posted tomorrow when I get the final diagnosis. He feels pretty certain that it's the fan relay. When I told him about the issue his first question was: "does your air conditioning work poorly when the temperature gauge starts to rise?". His assumption was correct - the air conditioning doesn't work well when the car gets hot. He believes that one fan is working which is marginally enough to keep the car from overhearing, and the other one is not coming on, so the engine doesn't cool properly and the a/c doesn't work properly.
Odd Posts
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Joined: Dec 2007
Posts: 3,633
Likes: 53
From: Ottawa, Ontario
Dennis,
A couple of thoughts
(1) I highly recommend the LN 160F thermostat. I find that the car runs cooler on the highway and will cool more quickly once it gets hot.
(2) The manual fan control "hack" has been great as well. When the car get to 200F + I can turn it on and actually watch the car cool to 190F while sitting still as it turns on the high speed fans.
A couple of thoughts
(1) I highly recommend the LN 160F thermostat. I find that the car runs cooler on the highway and will cool more quickly once it gets hot.
(2) The manual fan control "hack" has been great as well. When the car get to 200F + I can turn it on and actually watch the car cool to 190F while sitting still as it turns on the high speed fans.
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Three Wheelin'
Joined: May 2010
Posts: 1,851
Likes: 9
From: Nor Cal
Just an observation I've seen a lot of suggestions above for improvements to the cooling system which is great. But I would be afraid to start throwing parts at this without troubleshooting the root cause. The bottom line is 250F and overheating is not normal. Perhaps there is air in the system, low coolant level, your fans are not working, or you have a sensor problem. It sounds like you have the car at a good shop.
Also, did you test the coolant with a hydrometer?
Also, did you test the coolant with a hydrometer?
Thread Starter
Rocky Mountain High
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Joined: Aug 2007
Posts: 19,500
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From: Kolorado
I just heard back from the shop. It turns out that the fan wiring and relays are good, however both fans are defective. One isn't working at all and one isn't working properly. Both are being replaced.
