Opening hood to allow quicker cooldown - good or waste of time?
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E63 AMG
Opening hood to allow quicker cooldown - good or waste of time?
Prior to owning my E63, I never popped the hood on any of my other vehicles after going on a drive. Forced induction or not. I’ve seen it mentioned here a few times that’s it beneficial to do this on our cars for the purpose of prolonging the longevity of the plastic and rubber components underneath.
So it got me thinking. Isn’t it bad for certain components to experience a quicker cooldown? Like for example metal expanding and contracting too fast?
Overall, I just want to know from you guys on whether or not popping the hood after driving has little to no benefit? Thanks.
So it got me thinking. Isn’t it bad for certain components to experience a quicker cooldown? Like for example metal expanding and contracting too fast?
Overall, I just want to know from you guys on whether or not popping the hood after driving has little to no benefit? Thanks.
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2014 E63S; AMS 100 octane ECU dyno tune; EDOK TCU tune; BB intakes; sprintbooster
Have been doing this for years - especially after spiriting driving... no evidence that it helps but it just makes sense- especially in summer ambient garage temps. The contrary about worry it would cool too fast doesn't bother me..
the heat just bakes the plastics, hoses, etc....
the other benefit is that it forces me to survey the engine bay for obvious leaks or badness etc; also I have the always-on-IC-pump mod so I'll toggle that as well after a drive and I clip on the battery tender
the heat just bakes the plastics, hoses, etc....
the other benefit is that it forces me to survey the engine bay for obvious leaks or badness etc; also I have the always-on-IC-pump mod so I'll toggle that as well after a drive and I clip on the battery tender
Last edited by PeterUbers; Mar 25, 2023 at 05:04 PM.
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From: Boston area
2016 E63 Wagon
Definitely.
It has been proven that the extreme heat cycles absolutely does make plastic more brittle.
There was guy over on the M5 board that actually the did the work and measured the temperature, it was quite drastic difference during the first hours. And that was on a NA engine.
The cool to fast argument is a non issue. Air can never cool down metal (or plastic) fast enough to make any kind of damage, the thermal conductivity is simply too low.
It has been proven that the extreme heat cycles absolutely does make plastic more brittle.
There was guy over on the M5 board that actually the did the work and measured the temperature, it was quite drastic difference during the first hours. And that was on a NA engine.
The cool to fast argument is a non issue. Air can never cool down metal (or plastic) fast enough to make any kind of damage, the thermal conductivity is simply too low.
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E63 AMG
Definitely.
It has been proven that the extreme heat cycles absolutely does make plastic more brittle.
There was guy over on the M5 board that actually the did the work and measured the temperature, it was quite drastic difference during the first hours. And that was on a NA engine.
The cool to fast argument is a non issue. Air can never cool down metal (or plastic) fast enough to make any kind of damage, the thermal conductivity is simply too low.
It has been proven that the extreme heat cycles absolutely does make plastic more brittle.
There was guy over on the M5 board that actually the did the work and measured the temperature, it was quite drastic difference during the first hours. And that was on a NA engine.
The cool to fast argument is a non issue. Air can never cool down metal (or plastic) fast enough to make any kind of damage, the thermal conductivity is simply too low.
Out Of Control!!
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2014 E63S; AMS 100 octane ECU dyno tune; EDOK TCU tune; BB intakes; sprintbooster
Definitely.
It has been proven that the extreme heat cycles absolutely does make plastic more brittle.
There was guy over on the M5 board that actually the did the work and measured the temperature, it was quite drastic difference during the first hours. And that was on a NA engine.
The cool to fast argument is a non issue. Air can never cool down metal (or plastic) fast enough to make any kind of damage, the thermal conductivity is simply too low.
It has been proven that the extreme heat cycles absolutely does make plastic more brittle.
There was guy over on the M5 board that actually the did the work and measured the temperature, it was quite drastic difference during the first hours. And that was on a NA engine.
The cool to fast argument is a non issue. Air can never cool down metal (or plastic) fast enough to make any kind of damage, the thermal conductivity is simply too low.
extreme heat cycles makes plastic more brittle - sure. This guy showed the improved open hood cooling actually prolonged the life of the plastics? I'm probably misunderstanding, you're meaning to say he showed that open hood vs closed hood showed a difference in rate of cooling. But he couldn't have actually determined if this prolonged the life of the parts.
my thought is that a typically driven car and typical summer ambient conditions can bake and bake and bake those plastic parts for tens of thousands of miles while the engine is on and running and during spirited driving. That's even with the engine fan going. That being said, the engine usually takes about 2 to 3 hours to cool down when off, that's what the hood down and over the course of time what difference does a few hundred hours of prolonged cooling matter to several thousand hours of driving and baking those parts. What are your thoughts
what kind of experiment and control did he run?
Last edited by PeterUbers; Mar 26, 2023 at 10:04 AM.
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1991 964 Turbo, 2002 Black E55, 2002 Black E55 " The Beast"- 2014 E63s
Easy answer is, touch the various engine parts after an hour of normal driving with hood closed and open and see how significantly cooler the engine is with the hood open.
I always open the hood when ever I park my car in the garage with the fan standing on the side of the fender to blow away the hot air and within an hour or so, engine is cool enough to be touched
This ain't no rocket science and no scientific experiment to prove, just common sense
I always open the hood when ever I park my car in the garage with the fan standing on the side of the fender to blow away the hot air and within an hour or so, engine is cool enough to be touched
This ain't no rocket science and no scientific experiment to prove, just common sense
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2014 E63S; AMS 100 octane ECU dyno tune; EDOK TCU tune; BB intakes; sprintbooster
Easy answer is, touch the various engine parts after an hour of normal driving with hood closed and open and see how significantly cooler the engine is with the hood open.
I always open the hood when ever I park my car in the garage with the fan standing on the side of the fender to blow away the hot air and within an hour or so, engine is cool enough to be touched
This ain't no rocket science and no scientific experiment to prove, just common sense
I always open the hood when ever I park my car in the garage with the fan standing on the side of the fender to blow away the hot air and within an hour or so, engine is cool enough to be touched
This ain't no rocket science and no scientific experiment to prove, just common sense
just curious if it makes a significant difference in the life of the parts to open the hood or not. Like scientifically, any level of science.
good discussion, cheers.
Last edited by PeterUbers; Mar 26, 2023 at 11:13 AM.
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nope, it's not rocket science. It's definitely common sense that the parts are cooler when I touch them after an hour with the hood open.
just curious if it makes a significant difference in the life of the parts to open the hood or not. Like scientifically, any level of science.
good discussion, cheers.
just curious if it makes a significant difference in the life of the parts to open the hood or not. Like scientifically, any level of science.
good discussion, cheers.
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Out Of Control!!
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2014 E63S; AMS 100 octane ECU dyno tune; EDOK TCU tune; BB intakes; sprintbooster
Some advantages to not opening the hood could be to keep the engine closer to operating temp for back to back trips therefore less wear and tear on the block, some people believe a prolonged cooling period is safer for parts than quick cooling, but alas I've not found anything more than anecdotal testimony.
i still pop my hood though lol.
Last edited by PeterUbers; Mar 26, 2023 at 03:50 PM.
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From: Was, Cali, 95XXX, now Bavaria 91XXX
993 cab, 2014 E63 AMG 4matic T
First action after I purchased the car was to take off all the engine covers, even the foam pads on top of the coils. I don't think trapped heat is good for any components.
Of course I open the hood after I stressed the engine. Only at home though.
I even considered installing a fan on top of the ecu.
Of course I open the hood after I stressed the engine. Only at home though.
I even considered installing a fan on top of the ecu.
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1991 964 Turbo, 2002 Black E55, 2002 Black E55 " The Beast"- 2014 E63s
Funny you mentioned that, I have been driving without the engine cover for the past year or so, it's cosmetic anyway, so it's off
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If the engineers implemented they did it for a reason right? Remember turbo timers? I used to install those.
Some advantages to not opening the hood could be to keep the engine closer to operating temp for back to back trips therefore less wear and tear on the block, some people believe a prolonged cooling period is safer for parts than quick cooling, but alas I've not found anything more than anecdotal testimony.
i still pop my hood though lol.
Some advantages to not opening the hood could be to keep the engine closer to operating temp for back to back trips therefore less wear and tear on the block, some people believe a prolonged cooling period is safer for parts than quick cooling, but alas I've not found anything more than anecdotal testimony.
i still pop my hood though lol.
Interesting take on this one actually, especially the thermal differences/thermal shock but I guess after a spirited drive, letting it cool down for a bit doesn't hurt or if the spirited drive concludes the journey for the day, operating temperatures wouldn't had mattered in that case.
Either way not a bad idea depending on the situation.
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MBWorld God!
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First action after I purchased the car was to take off all the engine covers, even the foam pads on top of the coils. I don't think trapped heat is good for any components.
Of course I open the hood after I stressed the engine. Only at home though.
I even considered installing a fan on top of the ecu.
Of course I open the hood after I stressed the engine. Only at home though.
I even considered installing a fan on top of the ecu.
Last edited by W205C43PFL; Mar 26, 2023 at 05:38 PM.
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From: NYC
E63S
Top Gears' "8 Practices that will help keep your car in tip-top shape"
Above link is by no means irrefutable scientific data, but seems to be common practice as per Google search results. Also, who can argue with "It just makes sense!" lol! Besides the saving the plastics and rubbers bit... I do it also to aid shut off the cooling fans sooner. Ever notice how long they are on after shut down (especially when it's hot out)? I just see it as something that takes no effort you can do in order to make one's life possibly a bit less complicated and expensive, lol!
Above link is by no means irrefutable scientific data, but seems to be common practice as per Google search results. Also, who can argue with "It just makes sense!" lol! Besides the saving the plastics and rubbers bit... I do it also to aid shut off the cooling fans sooner. Ever notice how long they are on after shut down (especially when it's hot out)? I just see it as something that takes no effort you can do in order to make one's life possibly a bit less complicated and expensive, lol!
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2011 E63 AMG, 2007 S550 AMG
Great advice, we are enthusiasts we want to see the engine, not a cover that covers everything up. I doubt it (as in seriously doubt it) but I wonder if the engine is more prone to damage without a "cover" from road debris and water, I guess think of it as a screen protector on a screen (except not really). I mean people pressure wash their engine so I guess it wouldn't be an issue at least when water is concerned (like heavy rain), thoughts?
MBWorld God!
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For sure, our engine are beautiful in (to) our enthusiastic hearts. I understand a regular customer that don't care about cars don't want to see it but for us we do want to see it.
MBWorld God!
Joined: Dec 2019
Posts: 32,231
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MBWorld God!
Joined: Dec 2019
Posts: 32,231
Likes: 6,284
Top Gears' "8 Practices that will help keep your car in tip-top shape"
Above link is by no means irrefutable scientific data, but seems to be common practice as per Google search results. Also, who can argue with "It just makes sense!" lol! Besides the saving the plastics and rubbers bit... I do it also to aid shut off the cooling fans sooner. Ever notice how long they are on after shut down (especially when it's hot out)? I just see it as something that takes no effort you can do in order to make one's life possibly a bit less complicated and expensive, lol!
Above link is by no means irrefutable scientific data, but seems to be common practice as per Google search results. Also, who can argue with "It just makes sense!" lol! Besides the saving the plastics and rubbers bit... I do it also to aid shut off the cooling fans sooner. Ever notice how long they are on after shut down (especially when it's hot out)? I just see it as something that takes no effort you can do in order to make one's life possibly a bit less complicated and expensive, lol!
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Although not entirely related to the topic we are discussing, I found this market dependent decision by MB rather interesting: https://mbworld.org/forums/s-class-w...od-covers.html
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2016 E63 Wagon
fascinating - thank you for this - link please if you can find it would love to read it
extreme heat cycles makes plastic more brittle - sure. This guy showed the improved open hood cooling actually prolonged the life of the plastics? I'm probably misunderstanding, you're meaning to say he showed that open hood vs closed hood showed a difference in rate of cooling. But he couldn't have actually determined if this prolonged the life of the parts.
my thought is that a typically driven car and typical summer ambient conditions can bake and bake and bake those plastic parts for tens of thousands of miles while the engine is on and running and during spirited driving. That's even with the engine fan going. That being said, the engine usually takes about 2 to 3 hours to cool down when off, that's what the hood down and over the course of time what difference does a few hundred hours of prolonged cooling matter to several thousand hours of driving and baking those parts. What are your thoughts
what kind of experiment and control did he run?
extreme heat cycles makes plastic more brittle - sure. This guy showed the improved open hood cooling actually prolonged the life of the plastics? I'm probably misunderstanding, you're meaning to say he showed that open hood vs closed hood showed a difference in rate of cooling. But he couldn't have actually determined if this prolonged the life of the parts.
my thought is that a typically driven car and typical summer ambient conditions can bake and bake and bake those plastic parts for tens of thousands of miles while the engine is on and running and during spirited driving. That's even with the engine fan going. That being said, the engine usually takes about 2 to 3 hours to cool down when off, that's what the hood down and over the course of time what difference does a few hundred hours of prolonged cooling matter to several thousand hours of driving and baking those parts. What are your thoughts
what kind of experiment and control did he run?
And sorry - yes, he just proved that temps under the hood are much higher parked than when driving (which makes sense since while driven there is constant airflow through the engine compartment). He did NOT prove plastic part life, should have been clearer.
So to answer your other question - it's less of the duration of temps while driving (which we can't do much about), but the spike in temp that happens when parked with hood closed.
Is there a placebo effect? Maybe.....
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E63 AMG
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From: Boston area
2016 E63 Wagon
I tend to agree - since we have the electric after run pump.
That is mainly a leftover from the old turbo days of no water cooling and no afterun pump.
That said - after any hot run (like track days) it's always smart to run at a leisurely pace for a little bit (cool down lap) to let brakes, exhaust, and car in general cool off a bit from the airflow.
That is mainly a leftover from the old turbo days of no water cooling and no afterun pump.
That said - after any hot run (like track days) it's always smart to run at a leisurely pace for a little bit (cool down lap) to let brakes, exhaust, and car in general cool off a bit from the airflow.
Last edited by FastWgn; Mar 27, 2023 at 11:14 AM.
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E63 AMG
I tend to agree - since we have the electric after run pump.
That is mainly a leftover from the old turbo days of no water cooling and no afterun pump.
That said - after any hot run (liek track days) it's always smart to run as a leisurely pace for a little bit (cool down lap) to let brakes, exhaust, and car in general cool off a bit from the airflow.
That is mainly a leftover from the old turbo days of no water cooling and no afterun pump.
That said - after any hot run (liek track days) it's always smart to run as a leisurely pace for a little bit (cool down lap) to let brakes, exhaust, and car in general cool off a bit from the airflow.
