Turbo Cool Down time after spirited driving??

[Aftershock00]

Hello, let me first say that I have read all existing threads on this topic.
I have a 2017 cummins 4x4, it is not my daily driver so when I do drive it, it is either hauling firewood, hauling 6k lb TT, or just hot rodding around town. Well the other day I was hot rodding around town...basically, waiting for transmission to upshift to second and then leaning into WOT (for a few seconds) for that gear only. I guess you can call it a second gear pull. I was doing this with the exhaust brake on so as soon as I let off the throttle a few seconds later to slow down, the exhaust brake was really working hard. The truck was unloaded and only had a 1/4 tank of fuel. I then pulled up to house, backed in, and sat in truck for 45sec to a minute before turning off. I would say if you include backing in, engine was at idle speed for 2 minutes at best.

Question is, is this enough cool down time or did I probably coke my bearings? The manual doesn't really give cool down times for aggressive driving. It gives around time type driving and then loaded driving. I don't know enough about turbos to know if racing around town for 10 minutes unloaded is equal to, better or worse than driving for 3 hours at 70 with a 10k lb trailer as far as turbo heat is concerned.

Be advised, I always wait until coolant and oil temp are normal before making her work, so the engine gets warmed up properly. The thing I have to get used to is the cool down issue.

Also, I've read multiple times on this forum and others that's its actually good to keep the EB on at all times. My other questions is, does the hard deceleration caused by the EB activating at high rpm's (after hard acceleration) cause unnecessary wear and tear on transmission? Should I not have the EB on when racing around or is that what the truck is built to handle? I'm still trying to get a handle on the fine line between "that's what a HD truck is built to handle, you worry too much" and "hey man, are you TRYING to destroy you truck?"

Any guidance is appreciated, as I want to have fun with this truck but I don't want to destroy it.

 

[sag2]

The turbo is water cooled so It is pretty forgiving. Unless I'm towing or really working it hard, just the idling around the parking lot or into the neighborhood is all I ever do. If you waited until the temp was a couple hundred degrees you would never shut it down.

 

[Wiredawg]

Cool down:
towing heavy 3 to 5 minutes idling.
Hard driving solo at least 3 minutes

I always drive with EB on. No additional wear I can tell and not seen where others have either. Some also keep tow haul on as well, but on my Ram 5500 transmission special programming it's a bit too harsh.

I'm sure others will chime in,

Cheers,
Ron

 

[Jim W]

I am basing my response on my 2008 truck. This has the 6.7L Cummins and the 68RFE auto which I use to tow my 5er and is a daily driver when I need it. The Exhaust Braking feature is on 90 to 95% of the time when the truck is being driven. This will not hurt or damage the transmission, in fact using the EB feature is very beneficial to the Turbo Charger. This will help in keeping the sliding vane moving on the VGT of your truck.

When I am towing my 5er at highway speeds for 2+ hours (the EGT's are at 900F) I do not let the turbo cool down at all. Why all it takes is a couple of min's to cool the EGT's down. As I transition from on highway speeds to under 45 MPH like traveling on an off ramp, my EGT's will drop to around 400F which I will shut down the engine at that temperature.

On the 6.7L Cummins with a stock truck and programming, I have found out you will idle all day trying to get below 400F to 450F for the EGT's. Never achieving anything lower than 400F. So, this is the temps that I will shut down at.
Hope that helps? Others may chime in with their experience. Just remember that the 6.7L Cummins is a different model engine than the 5.9L Cummins. So, the results will be different.

 

[Aftershock00]

So I guess the real question is if turning the engine off prematurely can take thousands of miles off the life of the turbo/engine, why doesn't the onboard computer give some indication light when it is ok or not ok to shut off. Or make it prompt a warning when you attempt to shutoff saying "engine is still cooling and shutoff is not recommended, do you want to continue anyway?" It seems odd that with all this technology and the fact that this is a $65k plus vehicles, there would be a way to prevent this irreparable damage from happening so easily. I mean, I'm an ocd nutjob with my stuff. But most people I know, even mechanics/trademen, rarely, if ever, read an instruction manual, doesn't matter if its a truck or a lawnmower or a gun.

 

[Wiredawg]

Have any of you 4th geners installed an egt probe into the exhaust manifold. I know there are downstream factory egt probes and some folks read temps on those with aftermarket devices. I listed times above from old school experience

Cheers,

Ron

 

[DavidC]

I had read many years ago that if you run synthetic there is a lot less chance of coking the bearings. True or false ?

 

[GrantP]

To the OP, I think you're worried about nothing. My EGT's are between 3 and 4 hundred degrees by the time I coast through my neighborhood and get it in the garage. Never had an issue.

 

[Cummins2014]

To the OP, I think you're worried about nothing. My EGT's are between 3 and 4 hundred degrees by the time I coast through my neighborhood and get it in the garage. Never had an issue.

I think the OP should read the guidelines for cool down in the manual. Pretty straight forward on what to do.

 

[Wiredawg]

I think the OP should read the guidelines for cool down in the manual. Pretty straight forward on what to do.

Cummins2014 wins todays prize for the best answer!

Right out of the manual. I've read it before too as I always read the manuals of any new vehicles I purchase.
Seems all the technology AND two radiators has significantly improved cool down times.

When I'm towing heavy in grades during the Summer and pull off at a rest area, I come to a stop, the wife heads to the privy, while I let the truck idle and shoot the tires and axles with an infra red thermometer. It comes to about 5 minutes. Old habits, don't you know!

Nice call!

Cheers, Ron

 

[Learjet]

seems like my manual has some different info:

#ad

 

[Aftershock00]

Since I am the OP, I can tell you that I did read the manual as I stated in my original post. My question was on how to interpret that info based on my situation. The chart provided in the post above is great, but there is no category for making second gear full throttle pulls to almost redline. I am having trouble figuring out what category that does exist on the chart I can equate it to, hence why I asked for some feedback. There is also a column for turbo temperature, but again, if I don’t know what my turbo temp is, how can I figure out which guideline to use .
Maybe hot rodding with an empty truck and 1/4 fuel tank would be considered no load and not a big cause of turbo heat, or conversely , maybe hot rodding empty is the equivalent of calmly towing a 10k trailer at highway speeds up a hill. I don’t know, again, that’s why I am asking.

 

[AH64ID]

Hot rodding with WOT pulls will put the turbo into the warm area. EGT’s get high, but the short duration doesn’t heat the exhaust manifold and turbine housing to the same temp as towing. It will cool down faster than sustained towing because of this.

 

[TFucili]

Two minutes

 

[AH64ID]

Right out of the manual. I've read it before too as I always read the manuals of any new vehicles I purchase.
Seems all the technology AND two radiators has significantly improved cool down times.

I think that’s the ecodiesel chart. The 2500/3500 chart looks the same as my 05.

The dual radiators only lasted for 2 years, and then they went back to a single radiator in 2015.

Does anyone know if the HE300VG has a coolant passage around the bearing? Or is it just for the electronics?

 

[Cummins2014]

Since I am the OP, I can tell you that I did read the manual as I stated in my original post. My question was on how to interpret that info based on my situation. The chart provided in the post above is great, but there is no category for making second gear full throttle pulls to almost redline. I am having trouble figuring out what category that does exist on the chart I can equate it to, hence why I asked for some feedback. There is also a column for turbo temperature, but again, if I don’t know what my turbo temp is, how can I figure out which guideline to use .
Maybe hot rodding with an empty truck and 1/4 fuel tank would be considered no load and not a big cause of turbo heat, or conversely , maybe hot rodding empty is the equivalent of calmly towing a 10k trailer at highway speeds up a hill. I don’t know, again, that’s why I am asking.

Read the last one in the manual. Uphill Grade Maximum GCWR "Hot" "5" minute cool down. I think that covers whatever you are doing. Hell, if not let it idle for 10 minutes, if you don't think 5 will work or put in ETG gauge, no one is going to know unless they tow that same grade ,same gear, same load, and have an ETG gauge to tell you.

 

[Cummins2014]

I am basing my response on my 2008 truck. This has the 6.7L Cummins and the 68RFE auto which I use to tow my 5er and is a daily driver when I need it. The Exhaust Braking feature is on 90 to 95% of the time when the truck is being driven. This will not hurt or damage the transmission, in fact using the EB feature is very beneficial to the Turbo Charger. This will help in keeping the sliding vane moving on the VGT of your truck.

When I am towing my 5er at highway speeds for 2+ hours (the EGT's are at 900F) I do not let the turbo cool down at all. Why all it takes is a couple of min's to cool the EGT's down. As I transition from on highway speeds to under 45 MPH like traveling on an off ramp, my EGT's will drop to around 400F which I will shut down the engine at that temperature.

On the 6.7L Cummins with a stock truck and programming, I have found out you will idle all day trying to get below 400F to 450F for the EGT's. Never achieving anything lower than 400F. So, this is the temps that I will shut down at.
Hope that helps? Others may chime in with their experience. Just remember that the 6.7L Cummins is a different model engine than the 5.9L Cummins. So, the results will be different.

Same here, my previous truck I added the ETG gauge , If I waited for anything less then 400-450, it was going to be awhile, don't didn't care 400-450 was good for me. 16 years with that truck, seemed to work okay , never a turbo problem.

 

[Wiredawg]

I think that’s the ecodiesel chart. The 2500/3500 chart looks the same as my 05.

The dual radiators only lasted for 2 years, and then they went back to a single radiator in 2015.

Does anyone know if the HE300VG has a coolant passage around the bearing? Or is it just for the electronics?

Nope. Right out of the 2017 Ram 5500 Diesel Supplement. And my truck has dual radiators as I believe the 4th Gen P/Us do as well.

seems like my manual has some different info:

#ad

I guess I need to be careful about comparing Ram Cab and Chassis info with pickups. I guess C&Cs have more cooling capacity than the P/Us?

Cheers, Ron

 

[Learjet]

I think that’s the ecodiesel chart. The 2500/3500 chart looks the same as my 05.

Yep...just checked...looks similar to Eco diesel...maybe they lowered the time for all the EPA compliance crap on the 5500.

 

[AH64ID]

Nope. Right out of the 2017 Ram 5500 Diesel Supplement. And my truck has dual radiators as I believe the 4th Gen P/Us do as well.

The diesel supplement for 2017 covers 1500-5500. You're looking at the 1500 stuff. Try page 133.

As I said, the dual radiator was dropped after 2 years. It was only in pickups from 2013-2014.

As far as your dual radiator, got a pic? The stuff I'm reading says you should have the same cooling setup as the pickup, which is a single radiator.

I guess I need to be careful about comparing Ram Cab and Chassis info with pickups. I guess C&Cs have more cooling capacity than the P/Us?

Cheers, Ron

Just need to be sure you're reading info for your truck.

No, the C&C's don't have more cooling capacity and radiator configuration will have minimal impact on turbo cooldown times.