Cool down time
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Freshman User
Joined: Jan 2006
Posts: 43
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Cool down time
I have only had my 7.3 Truck for a couple months now so i am still new with the dos & donts of the Diesel world. My question is when you are done driving should you give the 7.3 any run time befor shuting it down? I know the Turbo guys do to cool the Turbo down. With the IDI no Turbo what do you do.
Also when you need to stop for 5-10 min for any reason than you will be back on your way should ya let Her run or shut down. Thanks
Also when you need to stop for 5-10 min for any reason than you will be back on your way should ya let Her run or shut down. Thanks
Fleet Mechanic
Joined: Sep 2005
Posts: 1,509
Likes: 3
From: Ladner, British Columbia
Cooldown
I don't know of anybody that cools down their non-turbo 7.3l.
The 93-94.5 turbo motors also had very conservative boost (7 psig max) so cooldown is not much of a concern. I would give it a minute or two if you just climbed up a steep hill and pulled over to the side of the road before you shut it down. My pyro temps usually drop below 500 F in less than a minute. Heck running around town I rarely get above 400 F.
I think the concern is more with the newer turbo Powerstroke motors that run higher turbo boost. I understand those engines need a cooldown before shutting down to get the exhaust and turbo temperature to drop and avoid risk cracking a manifold or damaging the turbo.
Seb.....
The 93-94.5 turbo motors also had very conservative boost (7 psig max) so cooldown is not much of a concern. I would give it a minute or two if you just climbed up a steep hill and pulled over to the side of the road before you shut it down. My pyro temps usually drop below 500 F in less than a minute. Heck running around town I rarely get above 400 F.
I think the concern is more with the newer turbo Powerstroke motors that run higher turbo boost. I understand those engines need a cooldown before shutting down to get the exhaust and turbo temperature to drop and avoid risk cracking a manifold or damaging the turbo.
Seb.....
Senior User
Joined: Mar 2006
Posts: 201
Likes: 0
From: San Carlos, CA
The cool down on any turbo can be helpful and recommended to give the impellers time to slow down.
I was told diesels like to stay nice and warm so my rule of thumb is to leave it on if I'm sitting in the truck for less than 15 minutes. Longer than that I shut it down. Less wear and tear on the sensitive starters and batteries as well.
I was told diesels like to stay nice and warm so my rule of thumb is to leave it on if I'm sitting in the truck for less than 15 minutes. Longer than that I shut it down. Less wear and tear on the sensitive starters and batteries as well.
Last edited by bl311; Sep 28, 2006 at 10:45 AM.
Posting Guru
Joined: Sep 2002
Posts: 1,897
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From: Northeastern Pa - USA
ya never put a wet horse in the barn ... the cool down time is not for letting the turbo spool down, it is to keep the oil from coking on the bearing. If you drive with lots of thought into your style, you wont need cool down time. Pace yourself when getting off the highway and looking for a parking spot. The big riggers let their trucks cool down because they are running hard most of the time, however, there are some who pull in and shut em down immediately. I suppose once ina while wont break the things that get gummed up.
My scooter gets lots of attention when running hard ... guages get looked at all the time ... an old pilot here and got in the habit of watching instruments. What can i say.
My scooter gets lots of attention when running hard ... guages get looked at all the time ... an old pilot here and got in the habit of watching instruments. What can i say.
Posting Guru
Joined: Oct 2003
Posts: 2,438
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From: Monroe, WA
No cool down necessary on a non-turbo'd engine. If it's going to run longer then a few minutes shut it off. Diesel is expensive! Only reason not to is if your starter or batteries have issues, or you engine starts hard. A easy starting engine doesn't hurt parts.
Senior User
Joined: Mar 2006
Posts: 201
Likes: 0
From: San Carlos, CA
Bilder, totally in agreement with you in that letting the truck idle is to prevent breaking down the little bit of oil left in the turbo housing, that is the end result. Just cut my reply short as that wasn't really Gold Dogs question. I always read that damage to turbo bearings and viscosity breakdown was primarily due to high impeller RPM's in stagnate oil on sudden shutdown. The oil temperature while idling isn't changing (up or down) much during this short duration but the recirculation is preventing the oil from overheating and breaking down. The only variable that we can control is letting the impellers wind down while oil is circulating so that when we eventually turn off the engine, the impellers don't spin as long in stagnate oil. It's been 20 years since I've really paid attention to this (86 Mustang SVO) but that was the thinking back then but I think it still applies. The end result is as you said, prevent the oil from coking.
