Combating Shutdown Heatsoak- I finally did something about it

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my turbod 01 jetta with a timing belt always got the hood up treatment + now my 01 TT gets the same + even has a factory over run water pump that shuts off by a sensor. looking on VW forums shows earlier timing belt failures in hotter climates $$$$
 
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I remove the engine cover from each car and leave it on the garage shelf until the car is sold. It's there only for appearance; sound deadening is just a marketing spin. It retains heat at a time when shedding heat is a challenge for modern vehicles.
I'm going to disagree. At least on an ex's EcoBoost Fusion 1.5T there was a noticeable difference in how much of the direct-injector noise you heard with the engine cover removed. Now, that's probably a DI-specific thing. My old-fashioned 2010 Escape never even had an engine cover.
 
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I've never considered heat soak on any car I've ever owned. I've also never had a car overheat, no engine failures, nothing. Coincidence or proof this is a non-issue?
It's well documented on the 4.0L jeeps of that era. My Jeep will run at 210 all day every day.

This weekend I left it idling on a trail after doing some rock crawling while the others caught up and it started running on 3 cylinders. All I had to do is it the schrader valve on the fuel rail with a pen cap and allow it to spit out all the evaporated / boiled gas and it'll run on all 6 again.
 
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I borrowed an 86 f150 years ago with the straight six. It kept killing the battery and I recognized a fan sound at shutdown. Turned out it indeed had a arrow squirrel cage blower with a metal outlet pipe which followed the fuel rail and blew cool air across the rail and top of the engine upon shutdown. Ford oem.

some of the 80s cars with the first electric fans would run them 5 minutes after shutdown.

my s60 volvos, if you ran them hard, would run the under hood fan by design after turning them off. You had to be running them hard, however.
 
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I just idle my engine for ~ 1 minute plus after a long drive. Never a heat soak issue with turbo or non turbo vehicles i.e. 4.0 AMC, Subaru 2.5, Mazda CX7 turbo, 2021 CX5 turbo. Ed
 
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I've been aware of heat soak for awhile and generally don't think about it with the 4-cylinder Tacoma unless it's been doing stop-and-go in high ambient temps. In this circumstance I idle it inside the garage for a minute before shutdown, then use a desk fan on high speed for about 10 minutes, pointed up toward the engine from floor level.
The C4 Corvette was a different story, it had a very cramped engine bay and big iron block that would heat soak for a very long time. I simply ran the same fan in the same way after every drive, no matter the conditions. Never had a problem with either one.
I see the OP's creation as something interesting to build and kind of a hobby building this kind of stuff. And in this case probably unnecessary but still fun to put together I am sure.
 
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If the engine is off and the key is on run and the ac is switched on, the cooling fans will run in my civic. I think this removes a good amount of heat pretty quickly but you’ll have to twiddle your thumbs for a minute after shutdown.
 

alcyon

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I've been aware of heat soak for awhile and generally don't think about it with the 4-cylinder Tacoma unless it's been doing stop-and-go in high ambient temps. In this circumstance I idle it inside the garage for a minute before shutdown, then use a desk fan on high speed for about 10 minutes, pointed up toward the engine from floor level.
The C4 Corvette was a different story, it had a very cramped engine bay and big iron block that would heat soak for a very long time. I simply ran the same fan in the same way after every drive, no matter the conditions. Never had a problem with either one.
I see the OP's creation as something interesting to build and kind of a hobby building this kind of stuff. And in this case probably unnecessary but still fun to put together I am sure.
Thanks man.. Running a portable fan is a very good way to get cool moving air into the engine bay and push out the hot air. I did this project because I wanted it to be portable, so I dont have to move around fans. I also can use the system anywhere I park. Once the set temp is reached the fans cut off and the system is using minimal power, less than the radio. I Just need to remember to turn the system off the next start up or earlier. Running the fans while the engine is running is a no-no in this case. But then again, its easy to see when the system is on or off.
 

Pew

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I'm confused, is this for while the car is running idle, when it's off, or when the car is driving in normal traffic?
 

alcyon

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I'm confused, is this for while the car is running idle, when it's off, or when the car is driving in normal traffic?
When its off. Look at the video at 46.22 to get an idea. You can only hear the fans running and the engine isn't on. Also see the fans cut off when the target temp is reached . When this happens the system just reads the temp and display it. It uses miniscule amount of power at this time.
 
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Some cars are more susceptible to heat soak than others.

An econobox four cylinder driven gently won’t suffer.

A high performance car (horsepower comes from heat) with a crowded engine compartment will suffer. A V-12 twin turbo, for example, gets incredibly hot under the hood after shutdown.

My bud’s 1975 Mercedes 450SL had terrible wiring problems and rust as a result of heat soak. In the year, Mercedes put the cats (new for 1975) IN the exhaust manifolds, keeping all that heat right there under the hood, where it couldn’t escape. Under hood temperatures would soar on shut down. Naturally, we moved the cats to under the car, as was done in 1977 on, when we did the restoration.

The vent fan would be great on my V-12s. I love this idea. I just wish I could find room…
AMEN on the wiring and heat soak, when one of my coworkers told a woman customer, btw he was master ASE, about the wiring potential issues she wanted him fired. I seem to recall he was doing something under the hood maybe battery check. I personally, not thru AAP HELPED MAYBE 15 people with vapor lock fuel lines due to under hood heat on a wide range of vehicles, carried can of starter fluid.
 

SammyChevelleTypeS3

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Lots of ASE and others tell me they actually open their hoods after parking in the home garage to let out heat anytime its convenient after long trips. They say its a simple attempt done to prolong life of heat affected parts / wires / connectors under the hood. Seems logical yet I am certain some will say idiotic and foolish.
 
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I've seen tunes that will run the cooling fans after shutdown if conditions are right. Turbo timers were a big thing too, I had a friend with a nasty RSX Type-S turbo with a K24 swap with one. That engine made so much heat it was insane, I don't know how the hood still had paint on it. The headers ran sideways to the turbo and all that heat was right there.

If I've been a little on the meaner side I let my car idle for a bit before I shut it down, but my oil temps are well under control.
 

SammyChevelleTypeS3

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My Cherokee heat soaks pretty bad. To the point that it won't run if it gets shut off hot. Only Chrysler could make an EFI system that vapor locks. One neat thing with the Cherokee is it has a mechanical fan on the passenger side and electric fan on the driver's side. What I did was add in a dummy relay so I can control the electric fan when ever, but without setting a fan code. The electric fan will move air directly over the exhaust manifolds / catifolds and move enough air that it won't heat soak.

The downside is I have to remember to turn the fan off. But it does help. If we're on a trail and stopped, I'll turn on the fan for 10minutes and it'll flow enough air over the exhaust catifolds and keep everything cool enough post-shutdown that it won't heat soak.
I had an 2000 XJ that did that...there was an TSB for it to wrap the fuel rail with heat reflecting tape/wrap...made it better, but on very hot days...still had issues. Some owners on the forums would cut holes in their hoods and install louvers to let the heat escape.
 
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I had an 2000 XJ that did that...there was an TSB for it to wrap the fuel rail with heat reflecting tape/wrap...made it better, but on very hot days...still had issues. Some owners on the forums would cut holes in their hoods and install louvers to let the heat escape.
Mine had the wrap done prior to my ownership. I have three cherokee hoods sitting in my yard, very tempted to do louvers on one of them.

It never exceeds 210F nomatter how hard I beat on it. Just heat soaks
 
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If it is that much an issue I would remove some of the hood seal near the windshield. All the heat really needs is a small crack and will readily convect up out cooling very quickly. The wifes old G8 I removed the plastic fake scoop covers and it cooled down significantly faster. The old 73 Corvette 454 i would lift the hood and put a .5 inch spacer.

I can appreciate the High Tech approach to the problem but a low tech solution would be far superior IMO.
 
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