heat from the Engine Compartment After Stopping
07-21-2013, 04:27 PM
#1
Intermediate
Thread Starter
heat from the Engine Compartment After Stopping
Here's my question. How much heat comes from the engine bay after you stop and shut down?
I've been surprised at how hot the rear of the car is around the engine bay after a drive. I can only compare to my previous experience from front engine cars where I've never felt anything like this. But, the body surface temperatures on the rear deck lid and around the rear panels are surprisingly hot to the touch. My gauges are showing a coolant temp of 175F and between 200F and about 215F for oil for a typical drive.
I have checked the operation of the fan. It is running when the engine is on at these temps. Also, if I shut down the engine and turn the key to accessory power, the fan turns on then too. However, the fan doesn't run after the car is shut down. On a 997.2 yesterday, on the same PCA drive, I noticed that his fan kept running for a short period of time after shut down. Should mine do that too?
Some advice I read said make sure the last few miles on a drive is less aggressive and this will help dissipate the heat. I tried that last night. When I parked, it did seem like everything was cooler, but as the car sat the body heated up to a noticeable level as the engine dissipated heat. That said, I do believe this is a technique that I will apply regardless in the future.
One other observation is that there is significant heat emanating from the rear wheel wells. I'm confident that this isn't brake or tire problems, just the heat transfer from the engine.
Is all of this typical? I've seen that a plugged cat may cause this, but the car is running spot on perfect, so am doubtful that there is anything like that causing problems.
Searches here on this topic haven't uncovered anything. I did find some discussion on 6Speed, but that seemed inconclusive also.
2006 C4.
I've been surprised at how hot the rear of the car is around the engine bay after a drive. I can only compare to my previous experience from front engine cars where I've never felt anything like this. But, the body surface temperatures on the rear deck lid and around the rear panels are surprisingly hot to the touch. My gauges are showing a coolant temp of 175F and between 200F and about 215F for oil for a typical drive.
I have checked the operation of the fan. It is running when the engine is on at these temps. Also, if I shut down the engine and turn the key to accessory power, the fan turns on then too. However, the fan doesn't run after the car is shut down. On a 997.2 yesterday, on the same PCA drive, I noticed that his fan kept running for a short period of time after shut down. Should mine do that too?
Some advice I read said make sure the last few miles on a drive is less aggressive and this will help dissipate the heat. I tried that last night. When I parked, it did seem like everything was cooler, but as the car sat the body heated up to a noticeable level as the engine dissipated heat. That said, I do believe this is a technique that I will apply regardless in the future.
One other observation is that there is significant heat emanating from the rear wheel wells. I'm confident that this isn't brake or tire problems, just the heat transfer from the engine.
Is all of this typical? I've seen that a plugged cat may cause this, but the car is running spot on perfect, so am doubtful that there is anything like that causing problems.
Searches here on this topic haven't uncovered anything. I did find some discussion on 6Speed, but that seemed inconclusive also.
2006 C4.
07-21-2013, 05:20 PM
#2
Temps
My car does the exact same things are you mentioned. Same temps as well. Body panels also hot to the touch. No brake or tire problems here either, and the fan turns off with the key switch. I figured it was normal, but have not owned the car long enough to learn all its tendencies yet. 2006 C2S.
07-21-2013, 05:53 PM
#4
After the car has stopped and turned off, the engine heat is still monitored. If needed, the fan will automatically come on the cool the engine, even if turned off and the car is left locked. I've heard my fan come on by itself a number of times.
The engine area does get hot, but I can't really say if your car is normal or not, as I've never measured the heat on my car. But IMHO, it "feels" about the same as some turbo cars that I've owned in the past and turbos run hot. So I would say the NA 997.1 is hotter than your average NA engine.
The engine area does get hot, but I can't really say if your car is normal or not, as I've never measured the heat on my car. But IMHO, it "feels" about the same as some turbo cars that I've owned in the past and turbos run hot. So I would say the NA 997.1 is hotter than your average NA engine.
07-21-2013, 06:12 PM
#5
Drifting
Here's my question. How much heat comes from the engine bay after you stop and shut down?
I've been surprised at how hot the rear of the car is around the engine bay after a drive. I can only compare to my previous experience from front engine cars where I've never felt anything like this. But, the body surface temperatures on the rear deck lid and around the rear panels are surprisingly hot to the touch. My gauges are showing a coolant temp of 175F and between 200F and about 215F for oil for a typical drive.
I have checked the operation of the fan. It is running when the engine is on at these temps. Also, if I shut down the engine and turn the key to accessory power, the fan turns on then too. However, the fan doesn't run after the car is shut down. On a 997.2 yesterday, on the same PCA drive, I noticed that his fan kept running for a short period of time after shut down. Should mine do that too?
Some advice I read said make sure the last few miles on a drive is less aggressive and this will help dissipate the heat. I tried that last night. When I parked, it did seem like everything was cooler, but as the car sat the body heated up to a noticeable level as the engine dissipated heat. That said, I do believe this is a technique that I will apply regardless in the future.
One other observation is that there is significant heat emanating from the rear wheel wells. I'm confident that this isn't brake or tire problems, just the heat transfer from the engine.
Is all of this typical? I've seen that a plugged cat may cause this, but the car is running spot on perfect, so am doubtful that there is anything like that causing problems.
Searches here on this topic haven't uncovered anything. I did find some discussion on 6Speed, but that seemed inconclusive also.
2006 C4.
I've been surprised at how hot the rear of the car is around the engine bay after a drive. I can only compare to my previous experience from front engine cars where I've never felt anything like this. But, the body surface temperatures on the rear deck lid and around the rear panels are surprisingly hot to the touch. My gauges are showing a coolant temp of 175F and between 200F and about 215F for oil for a typical drive.
I have checked the operation of the fan. It is running when the engine is on at these temps. Also, if I shut down the engine and turn the key to accessory power, the fan turns on then too. However, the fan doesn't run after the car is shut down. On a 997.2 yesterday, on the same PCA drive, I noticed that his fan kept running for a short period of time after shut down. Should mine do that too?
Some advice I read said make sure the last few miles on a drive is less aggressive and this will help dissipate the heat. I tried that last night. When I parked, it did seem like everything was cooler, but as the car sat the body heated up to a noticeable level as the engine dissipated heat. That said, I do believe this is a technique that I will apply regardless in the future.
One other observation is that there is significant heat emanating from the rear wheel wells. I'm confident that this isn't brake or tire problems, just the heat transfer from the engine.
Is all of this typical? I've seen that a plugged cat may cause this, but the car is running spot on perfect, so am doubtful that there is anything like that causing problems.
Searches here on this topic haven't uncovered anything. I did find some discussion on 6Speed, but that seemed inconclusive also.
2006 C4.
07-21-2013, 06:28 PM
#6
.
Trending Topics
07-21-2013, 07:17 PM
#8
Rennlist Member
The fans often kick back on after about 15 minutes.
07-21-2013, 07:53 PM
#10
Race Director
Well, to add a bit more...
Lots of heat. The engine is essentially a 400lb lump of alum/iron/plastic filled with water and oil all at 200F or thereabouts. The tranny is another 200lbs of hot alum/steel and oil. Then there are the wheel/tires and brakes. and last but not least the exhaust system can be 4 or 5 times hotter. The converters operate at around 1000F.
If the compartment heat climbs too high the engine compartment fan should come on. Now that said the engine compartment fan my 02 Boxster only comes on if the car is not locked. My 03 Turbo I hear the fan come on even though the car is locked. With the Turbo even after the car has been parked a half an hour or so and I go back out I sometimes hear the fan running. There's a lot of heat to be shed by the engine/exhaust.
As UMSC_DS1 mentioned, I also used a fan when I parked the car in a garage. I'd turn on the fan low speed and let it blow air from the front of the car aimed mostly down to help create a bit of high pressure under the car and force the heated air out of the compartment.
I no longer have a garage so the car just gets whatever cooling it gets from the breeze.
Whenever possible I do try to park the car heading into the wind but many is the time I can't do this or there is no wind to speak of and well, the car has not apparently suffered any from this.
Lots of heat. The engine is essentially a 400lb lump of alum/iron/plastic filled with water and oil all at 200F or thereabouts. The tranny is another 200lbs of hot alum/steel and oil. Then there are the wheel/tires and brakes. and last but not least the exhaust system can be 4 or 5 times hotter. The converters operate at around 1000F.
If the compartment heat climbs too high the engine compartment fan should come on. Now that said the engine compartment fan my 02 Boxster only comes on if the car is not locked. My 03 Turbo I hear the fan come on even though the car is locked. With the Turbo even after the car has been parked a half an hour or so and I go back out I sometimes hear the fan running. There's a lot of heat to be shed by the engine/exhaust.
As UMSC_DS1 mentioned, I also used a fan when I parked the car in a garage. I'd turn on the fan low speed and let it blow air from the front of the car aimed mostly down to help create a bit of high pressure under the car and force the heated air out of the compartment.
I no longer have a garage so the car just gets whatever cooling it gets from the breeze.
Whenever possible I do try to park the car heading into the wind but many is the time I can't do this or there is no wind to speak of and well, the car has not apparently suffered any from this.
07-21-2013, 08:23 PM
#11
Drifting
Here's the simple solution at work. The heat coming throw the other end(driver side wheel) is noticeably hot at first. During the hotter summer days I'll also crack the garage door a few inches to allow the hot air moving at ground level to get pushed by the fan outside the garage vs. just circulating inside garage. I'll typically connect the trickle charger when I park her inside the garage to just keep a full charge even if the engine fan may kick in now and then... especially during our triple digit days.
Like Macster I try to get the engine's heat evac'd whenever I can... I have no objective proof of the benefits but I suspect/believe that it's better over time to get the engine and exhaust heat out of the engine compartment especially if I can do so with a cheap floor fan vs. the Porsche engine fan... plus I like the idea of all those engine plastic and rubber parts getting some relief from the heat.
Like Macster I try to get the engine's heat evac'd whenever I can... I have no objective proof of the benefits but I suspect/believe that it's better over time to get the engine and exhaust heat out of the engine compartment especially if I can do so with a cheap floor fan vs. the Porsche engine fan... plus I like the idea of all those engine plastic and rubber parts getting some relief from the heat.
07-21-2013, 08:33 PM
#13
Intermediate
Thread Starter
:bowdown :bowdown x2!
Was able to procure the last turbo fan at the hardware store! I am now compliant :-)
Was able to procure the last turbo fan at the hardware store! I am now compliant :-)
Last edited by megsfolks; 07-21-2013 at 09:36 PM.
07-21-2013, 09:46 PM
#14
Racer
Join Date: Jul 2012
Location: West of Bean Town
Posts: 308
Likes: 0
Received 0 Likes
on
0 Posts
In the 911, the locations of all the hot parts are is the same area all dissipating heat.
In a front engine car, engine's on one end, exhaust on the other. Connecting them is several feet of exhaust pipe (think heat sink) allowing some cooling prior to getting to the mufflers.
In the 911, engine, headers and exhaust are right next to each other. Heat is concentrated there.
In a front engine car, engine's on one end, exhaust on the other. Connecting them is several feet of exhaust pipe (think heat sink) allowing some cooling prior to getting to the mufflers.
In the 911, engine, headers and exhaust are right next to each other. Heat is concentrated there.
07-21-2013, 11:04 PM
#15
Rennlist Member
Here's the simple solution at work. The heat coming throw the other end(driver side wheel) is noticeably hot at first. During the hotter summer days I'll also crack the garage door a few inches to allow the hot air moving at ground level to get pushed by the fan outside the garage vs. just circulating inside garage. I'll typically connect the trickle charger when I park her inside the garage to just keep a full charge even if the engine fan may kick in now and then... especially during our triple digit days.
Like Macster I try to get the engine's heat evac'd whenever I can... I have no objective proof of the benefits but I suspect/believe that it's better over time to get the engine and exhaust heat out of the engine compartment especially if I can do so with a cheap floor fan vs. the Porsche engine fan... plus I like the idea of all those engine plastic and rubber parts getting some relief from the heat.
Attachment 745937
Attachment 745938
Like Macster I try to get the engine's heat evac'd whenever I can... I have no objective proof of the benefits but I suspect/believe that it's better over time to get the engine and exhaust heat out of the engine compartment especially if I can do so with a cheap floor fan vs. the Porsche engine fan... plus I like the idea of all those engine plastic and rubber parts getting some relief from the heat.
Attachment 745937
Attachment 745938
