Temp rise under heavy engine load normal?
05-16-2008, 10:33 PM
#1
Temp rise under heavy engine load normal?
Today temepartue was 80 F, I had air conditioning at max.
The car is a Cayman S manual
Drove a 25 mile section of twisties (deserted , no cars) was pushing it, mostly second gear sections , then second gear uphilll twisties, sometimes third, but always changing gears at 6500 or 700 rpms.
During the middle of the uphill the needle of the temp rised to the second marker, I continued pushing it and having fun, and temp continued there, rised a tiney bit past the marker, then the downhill came and temp went back to normal.
I think this car is made for this type of driving, and Im surprised of the temp rise, is this normal?
Any harm to continue driving fast with the temp at the second mark in the gauge?
Also I have done this route many many times with my Triptronic 2.7 Boxster and Temperature never moved from center.
The car is a Cayman S manual
Drove a 25 mile section of twisties (deserted , no cars) was pushing it, mostly second gear sections , then second gear uphilll twisties, sometimes third, but always changing gears at 6500 or 700 rpms.
During the middle of the uphill the needle of the temp rised to the second marker, I continued pushing it and having fun, and temp continued there, rised a tiney bit past the marker, then the downhill came and temp went back to normal.
I think this car is made for this type of driving, and Im surprised of the temp rise, is this normal?
Any harm to continue driving fast with the temp at the second mark in the gauge?
Also I have done this route many many times with my Triptronic 2.7 Boxster and Temperature never moved from center.
05-17-2008, 05:43 PM
#2
Race Director
During a drive arcross southern AZ in my '02 Boxster with ambient...
Today temepartue was 80 F, I had air conditioning at max.
The car is a Cayman S manual
Drove a 25 mile section of twisties (deserted , no cars) was pushing it, mostly second gear sections , then second gear uphilll twisties, sometimes third, but always changing gears at 6500 or 700 rpms.
During the middle of the uphill the needle of the temp rised to the second marker, I continued pushing it and having fun, and temp continued there, rised a tiney bit past the marker, then the downhill came and temp went back to normal.
I think this car is made for this type of driving, and Im surprised of the temp rise, is this normal?
Any harm to continue driving fast with the temp at the second mark in the gauge?
Also I have done this route many many times with my Triptronic 2.7 Boxster and Temperature never moved from center.
The car is a Cayman S manual
Drove a 25 mile section of twisties (deserted , no cars) was pushing it, mostly second gear sections , then second gear uphilll twisties, sometimes third, but always changing gears at 6500 or 700 rpms.
During the middle of the uphill the needle of the temp rised to the second marker, I continued pushing it and having fun, and temp continued there, rised a tiney bit past the marker, then the downhill came and temp went back to normal.
I think this car is made for this type of driving, and Im surprised of the temp rise, is this normal?
Any harm to continue driving fast with the temp at the second mark in the gauge?
Also I have done this route many many times with my Triptronic 2.7 Boxster and Temperature never moved from center.
Do not remember what the in-dash gage indicated.
When I returned to my dealership I mentioned this to service manger and he spoke with the factory and the response was that if the overheating or low coolant or low oili pressure warning lights not on/flashing there was no problem.
It is hard and hot work to pull a car up a hill and the higher the elevation the harder it becomes. Rev'ing engine out to 6800 to 7000 of coures increases the amount of heat the engine produces and the amount of heat hte cooling system must shed.
As the elevation increases, engine output decreases and there is less air to flow through radiators. You might have been better off switching A/C to 72 degs .and automatic mode or even shutting the A/C off to help reduce the amount of heat the A/C condensors were emitting -- they reside just ahead of the radiators and tend to heat the incoming air just before this air gets to the radiators.
Even so, though I'm going to say nothing you or the car or the engine experienced was out of the ordinary and no damge occurred. Frankly, had there been any problems you'd know about it pretty guick.
I can't help but touch upon the importance of keeping fresh/clean oil of the proper type/grade in engine. In my Boxster's case, it experienced that severe heat with oil no older the 5000 miles (I change the oil/filter every 5000 miles). I'd hate to subject it tp those conditions with oil with 15,000 miles on it...
Sincerely,
Macster.
05-20-2008, 11:43 AM
#3
Rennlist Member
05-20-2008, 09:52 PM
#4
Race Director
A day or so back had the chance to drive up an incline with many curves...
Today temepartue was 80 F, I had air conditioning at max.
The car is a Cayman S manual
Drove a 25 mile section of twisties (deserted , no cars) was pushing it, mostly second gear sections , then second gear uphilll twisties, sometimes third, but always changing gears at 6500 or 700 rpms.
During the middle of the uphill the needle of the temp rised to the second marker, I continued pushing it and having fun, and temp continued there, rised a tiney bit past the marker, then the downhill came and temp went back to normal.
I think this car is made for this type of driving, and Im surprised of the temp rise, is this normal?
Any harm to continue driving fast with the temp at the second mark in the gauge?
Also I have done this route many many times with my Triptronic 2.7 Boxster and Temperature never moved from center.
The car is a Cayman S manual
Drove a 25 mile section of twisties (deserted , no cars) was pushing it, mostly second gear sections , then second gear uphilll twisties, sometimes third, but always changing gears at 6500 or 700 rpms.
During the middle of the uphill the needle of the temp rised to the second marker, I continued pushing it and having fun, and temp continued there, rised a tiney bit past the marker, then the downhill came and temp went back to normal.
I think this car is made for this type of driving, and Im surprised of the temp rise, is this normal?
Any harm to continue driving fast with the temp at the second mark in the gauge?
Also I have done this route many many times with my Triptronic 2.7 Boxster and Temperature never moved from center.
Hauling a 3000lb+ car up a pretty steep hill (mountain I guess with the pass elevation around 1400ft or so (high enough my ears pop a bit) in the space of maybe 6 miles in 2nd and 3rd gear is hot work.
'course, as you also noted the coolant temperature dropped considerably once car was on the downslope of the mountain. By time I had traveled maybe another 6 miles or so and came to a 4-way stop sign coolant temperature down to 199 degs. F.
Will add I had A/C on auto whole time and temperature set to 72 degs. F.
As long as you don't smell coolant/antifreeze and the coolant and oil levels are good and remain constant car is ok.
The newer Boxsters have somewhat improved cooling compared to the earlier model years. I note even after my '02 there were several years in which Porsche specifically mentioned improved cooling and yet my '02 even under what I would consider pretty harsh and high ambient temperature conditions has not exhibited any overheating symptoms.
While you can add a 3rd radiator as someone suggested but I think it overkill.
I've read reports of water cooled Boxsters and Carreras holing a radiatior and the driver/navigator clamp the hoses to the broken radiator and continue on with just one. There is quite a bit of excess cooling capacity in these cars. This of course is true only if the cooling system is able to maintain pressure. It is the pressure that keeps the coolant liquid and prevents it from flashing to steam at the hottest spots in mainly the heads around the exhaust ports.
If the system can't hold pressure localized overheating can occur when the coolant flashes to steam and this steam helps prevent liquid coolant from flowing over the hot spot. The temperature gage may not even rise but damage could occur. The alum. in the head can get hot enough to lose some strength and soften and thus the head hold down in that area do not clamp with as much force and a head gasket leak is almost certain to develop.
Sincerely,
Macster.
