6.7L Cummins Forum

Does anyone know if it is necessary to let truck run awile before turning off to let turbo cool down after driving?

Yes. If you look in your owner's manual it does talk about this and be anything from 1 to 2 minutes all the way up to 5 minutes depending on how the truck was driven. Should be page 280 in your manual.

Hope that helps.

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what happens if you don't let it run?? How hot does it get and what is the tuurbo made of?

Woodsy22,
A cummins mechanic told my father that this engine can run at 1300 f all day long, but I have seen some reports of temps up around 1500 f. Keep in mind that these high temps also help the emissions systems in your exhaust work more effeciently. I always let my engine idle a couple of minutes if I have been towing or working the engine harder than a trip to the grocery store. I also will be installing a exhaust temp system next week so I can actually see what my temps are. Hope this helps!

It is not so much how hot things can get but what happens when oil and water stops following at shutdown. When you turn off the engine, oil and water to the turbo stops following yet it still spins for a while and that is happening with no oil flow. This oil being exposed to prolong hi temps will have coking issues. That will cause seals to fail and oil passages to become blocked.

BTW, if you have a fully working smog system with DPF, be careful of EGT over 1250 degrees. If memory serves correctly, at 1275 and above will damage the DPF ....

Hope that helps.

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I've seen pre turbo temps of 1,600+ on mine, short spikes lasting less than 1 minute, kind of scary if you ask me. It is odd because where I would think the temps would rise to that level (Heavy upgrade towing), it usually hangs around 1,100 to 1,200. normal flat driving, no load it sets at 1,000 most all of the time. As far as shut off temps go, mine is around the 500 to 600 area, I don't see 400 or less even with an idle down for any real length. 75,000 miles with the original turbo (never cleaned) and emmissions system intact. Go figure.

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07.5 3500 Quad, SRW, 4X4, Laramie, Leathered, Dark Metallic Gray, 6.7, 68RFE, 20K Reese, Ride Rite's, 2 Viair air compressors, Bully steps, Kleinn Locomotive air horns (5 in all), Billet polished locking fuel door, 'A' pillar mount Auto Meter Pryo, PML X-deep trans pan
06 Durango 285 RL 5'er Lifted by KZ

Here's what the service manual says

Attached Files

TURBOCHARGER cooldown.doc (27.0 KB, 18 views)

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2007.5 Dodge Ram 3500 HD,QC, 6.7L Cummins, 6speed Auto, 4X4, Bighorn Edition.
Click for installs: Carr Steps PML Diff Cover Edge Juice with Attitude Volant Intake Hankook ATM RF10

I looked in my Owners Manual from front to back and there is no mention of a cool down period. You would think that if it was important (and I'm not saying it isn't) there would be something written in the manual.

The thing I thought was funny is how is a person suppose to know if their Turbo is hot or not since they don't include a way to see it and according to Cummins they don't believe in using the EGT.

Quote:

Regarding your inquiry about EGT for Turbo Timer. Thanks for your Email message. You have contacted Cummins, Inc. at our Customer Assistance Center located in Columbus, Indiana. This is our worldwide headquarters and has been our home since Clessie Cummins founded the company February 3, 1919. Cummins does not provide maximum or minimum EGTs for our engines. The information is not very useful. The most expensive engines (V12 and V18) engines tend to mask single cylinder high exhaust temperatures in the average temperature as the exhaust gasses are mixed. Dash mounted pyrometers are seldom accurate and lag the actual exhaust gas temperatures by several seconds due to the durable shielding needed for the fragile thermocouple they use. In our research and development labs we measure the exhaust temps but do this before the turbocharger, where the information is more meaningful, using frequently calibrated pyrometers, in steady-state tests where the time lag is unimportant. It costs us considerable expense as the thermocouple shields often fail at the higher temperatures we achieve during higher than 100% fueling tests with higher than normal intake temperatures to accelerate power unit failures. The failed shields then pas through the turbos causing expensive damage. Our experience is that use of pyrometers for field applications of engines is most helpful when the instrument is used to watch for a change of EGT on an engine when running at similar conditions (intake air temperature, load, coolant temperature) experienced previously. This might help determine a dead cylinder. In rare instances, an engine overheat can be detected using a pyrometer but this would be more accurately reported by the coolant temperature gage. We thank you for your interest in Cummins products. We occasionally misunderstand a question. If our answer to your communication looks like we have misunderstood your e-mail please reply with further inquiry. To locate the nearest Cummins-authorized Dealer or Distributor Service Provider call our toll free customer assistance line 1-800-DIESELS (343-7357) or for computer assistance in locating a Service Provider, use Cummins Service Locator, which can be found on Cummins website: Cummins Inc. Homepage

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2007.5 Dodge Ram 3500 HD,QC, 6.7L Cummins, 6speed Auto, 4X4, Bighorn Edition.
Click for installs: Carr Steps PML Diff Cover Edge Juice with Attitude Volant Intake Hankook ATM RF10