cooldown really required?

Mountainman · **Posted:** Tue Apr 18, 2017 3:50 pm

This article claims that synthetic oils absolutely don't coke, and that cool-down is not required in modern diesels. What do you all think? :POPCORN:

http://bankspower.com/techarticles/show ... -&-Fiction

craws010 · **Posted:** Tue Apr 18, 2017 4:07 pm

I have been letting my VW TDI's cool down before shutdown for years and do the same with my F350. I suppose it might not be necessary. But it makes me feel better despite what the experts may say.

GordnadoCRD · **Posted:** Tue Apr 18, 2017 5:46 pm

coking isn't all the problem.

Shutting down too hot will damage the seals.

Shutting down without letting the turbo slow will spin the bearings with no oil flow (unless you've installed an accumulator or secondary electric oil pump)

geordi · **Posted:** Tue Apr 18, 2017 6:23 pm

The bearing in the turbo cannot "spin" b/c it is a sleeve bearing that is fixed in place by a locking pin.

Unless your driveway is at the end of a highway off ramp, the reality is your engine and EGT have already come down to acceptable levels in the 20-30 seconds of driving through neighborhood streets. Sitting with it is really only (maybe) needed when coming off of a hard mountain climb into a rest stop, while towing.

Even then... Sit there, close your eyes and just take ten deep breaths... And shut the engine off to go inside.

flash7210 · **Posted:** Tue Apr 18, 2017 7:31 pm

I trust Banks to be the experts on high performance diesel engines and turbochargers.
But...

I've got almost 200k miles on my factory turbo and have always practiced some form of turbo cooldown time.
I guess I'd rather be safe than sorry.

papaindigo · **Posted:** Tue Apr 18, 2017 8:37 pm

geordi pretty much sums up my feelings based on 2 D250 Cummins and 2 05 CRDs. A 0.5 mile or so on regular surface roads at 40 mph or less when you get off the interstate is fine. If you pull off the interstate to immediately gas up then cool down. A minute or so is worth it considering the cost of a turbo.

WWDiesel · **Posted:** Tue Apr 18, 2017 9:29 pm

It is super cheap insurance and certainly does not hurt a thing letting the engine idle for for a few minutes before shutting the engine off to let the oil temperature cool down a little bit. I always let the Jeep idle for several minutes before turning the key off! :wink:

My Dodge Cummins has a Turbo Cool Down timer that will automatically let the engine idle for several minutes even after you switch the key off. lock the truck, and walk away.... :mrgreen:

It was an add-on accessory!!!

Mountainman · **Posted:** Tue Apr 18, 2017 10:09 pm

WWDiesel wrote:

It is super cheap insurance and certainly does not hurt a thing letting the engine idle for for a few minutes before shutting the engine off to let the oil temperature cool down a little bit. I always let the Jeep idle for several minutes before turning the key off! :wink:

My Dodge Cummins has a Turbo Cool Down timer that will automatically let the engine idle for several minutes even after you switch the key off. lock the truck, and walk away.... :mrgreen:

It was an add-on accessory!!!

Thanks for all the comments everyone, I'll keep with my cooldowns, just incase.

wwdiesel- that sounds really nice, I'm actually in the market for a 3/4 ton diesel. It's gotta be an auto and I read bad things about the autos that they bolted to the 4 valves. I want the Cummins efficiency, but not transmission problems, so now I'm looking at Chevy's :/

mass-hole · **Posted:** Tue Apr 18, 2017 10:39 pm

I usually let it run in the garage as I unload and move stuff in the house. So usually 20-30 seconds.

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WWDiesel · **Posted:** Wed Apr 19, 2017 12:51 am

Mountainman wrote:

wwdiesel- that sounds really nice, I'm actually in the market for a 3/4 ton diesel. It's gotta be an auto and I read bad things about the autos that they bolted to the 4 valves. I want the Cummins efficiency, but not transmission problems, so now I'm looking at Chevy's :/

The only weak point I ever heard about was the torque converter on the auto box behind the 24 valve engines. They were too weak, kinda like the Jeep diesel TC's...
I went through 2 TC's before investing in the high dollar SunCoast TC and have had no transmission problems since and I tow a 10k trailer behind it.

Don't know about the later models, but early 24 valve engine 68RFE transmissions were really some tough transmissions according to my good friend who owns and runs a local transmission repair shop.

Watch out for Fords, heard they had lots of problems with their transmissions behind their diesels! I know several people who owned Fords diesels and transmissions had to be rebuilt...
As for Chevy / GMC, have not heard anything bad about their transmissions behind the Duramax....Allisons

Mountainman · **Posted:** Wed Apr 19, 2017 1:36 am

WWDiesel wrote:

Mountainman wrote:

wwdiesel- that sounds really nice, I'm actually in the market for a 3/4 ton diesel. It's gotta be an auto and I read bad things about the autos that they bolted to the 4 valves. I want the Cummins efficiency, but not transmission problems, so now I'm looking at Chevy's :/

The only weak point I ever heard about was the torque converter on the auto box behind the 24 valve engines. They were too weak, kinda like the Jeep diesel TC's...
I went through 2 TC's before investing in the high dollar SunCoast TC and have had no transmission problems since and I tow a 10k trailer behind it.

Don't know about the later models, but early 24 valve engine 68RFE transmissions were really some tough transmissions according to my good friend who owns and runs a local transmission repair shop.

Watch out for Fords, heard they had lots of problems with their transmissions behind their diesels! I know several people who owned Fords diesels and transmissions had to be rebuilt...
As for Chevy / GMC, have not heard anything bad about their transmissions behind the Duramax....Allisons

Thanks for the advice! I read the same about the fords. Is the Cummins forum the Place to go to find out how well put together the rams are? I need reliability for long distance deliveries.

WWDiesel · **Posted:** Wed Apr 19, 2017 12:52 pm

These are a couple I recommend:
https://dodgeforum.com/
select Dodge truck, then generation you interested in!

https://www.dieseltruckresource.com/forums/
select generation you interested in!
:SOMBRERO:

thermorex · **Posted:** Wed Apr 19, 2017 9:08 pm

Better safer than sorry, all manufacturers I know, recommend turbo cool down, so if they do it, I bet that's enough to warrant cooldown. Plus, takes few minutes at most.

Plus gordnado said it very well, it makes total sense.

dkenny · **Posted:** Fri Apr 21, 2017 7:26 pm

stay with the cummins and fix the tranny..do it before it goes bad..it won't cost as much.
more or less the same issue with the tranny's in the jeep..designed for a gas and put a diesel in front..
diesel are low rpm torque monsters....gasers aren't...this cause more slippage on the bands..
the line pressure is too low for the power the diesel puts out at the low rpm...
I had my tranny in my dodge diesel rebuilt...it now has higher line pressure at low rpm..
in know not jeep related..
-dkenny

Mountainman · **Posted:** Sat Apr 22, 2017 12:14 am

Thanks for the links WW and the transmission advise dk, I always loved the 2010 Cummins I got to have for a couple years with my energy industry job!

WWDiesel · **Posted:** Sat Apr 22, 2017 7:56 am

dkenny wrote:

stay with the cummins and fix the tranny..do it before it goes bad..it won't cost as much.
more or less the same issue with the tranny's in the jeep..designed for a gas and put a diesel in front..
diesel are low rpm torque monsters....gasers aren't...this cause more slippage on the bands..
the line pressure is too low for the power the diesel puts out at the low rpm...
I had my tranny in my dodge diesel rebuilt...it now has higher line pressure at low rpm..
in know not jeep related..
-dkenny

Adding the TransGo full kit will up transmission line pressure which helps put more pressure on the bands and clutches when they are engaged. It also make the shifts a little quicker and helps the bands and clutches last longer according to my good friend who owns and operates a transmission repair shop.... :wink:

dgeist · **Posted:** Sun Apr 23, 2017 9:08 am

I turn off the accessories and let it idle while I'm collecting my bag, phone, ID when I get to work. Take a look around you and pick up trash and take a moment to collect yourself and take a few cleansing breaths before you get out and start (or end) your day. That gives you 30 seconds of cooldown

Dan

MM53 · **Posted:** Mon Apr 24, 2017 4:15 pm

30 seconds of cooldown for normal driving or 1to2 minutes for extended interstate trips . 150k on OEM turbo no play.

Mountainman · **Posted:** Mon Apr 24, 2017 4:36 pm

MM53 wrote:

30 seconds of cooldown for normal driving or 1to2 minutes for extended interstate trips . 150k on OEM turbo no play.

That's what I've been doing with my Garrett that has about 35k on it, and it already has play. I'm not impressed, but maybe it has to do with the lack of the stock 'BOV' which the egr acted as. Or maybe I got a bad one, hmm

geordi · **Posted:** Tue Apr 25, 2017 1:19 am

That blow off valve nonsense is useless on a diesel. Your turbo doesn't need that b/c the cylinders are always inhaling air and reducing the pressure in the intake whether fuel is being used or not. BOVs are needed with engines that have a throttle plate. Diesels don't.

cooldown really required?

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