I've read quite a few threads on this forum and others that in order to help with the longevity of our turbos we need to let the turbo cool down before turning off the truck in order to prolong the longevity of the turbo (bearings?). That being said, I have a CTS2 and would like to know what is the best PID to monitor for this and what the "value" should be? I read somewhere that EGT 4 should be below 400 degrees?

Thanks!

 

I'm not an expert on the subject but I monitor EGT1 and personally once it get's to 450° I call it good. I live a couple mile out of town up in the hills so it's a climb every time I come home. If I am empty it usually only takes a minute or two.

 

Very helpful. Thanks!

 

Just for a bit of insight, I'll try to break down the whole turbo cooldown thing.

The potential issue with running a turbo hot and then shutting off the engine is a phenomenon known as "coking". This is where hot oil sits with nowhere to go and basically cooks in place. Over time you get deposits that build up, flow is restricted, and eventually the bearings are starved and fail.

Now as terrible as that sounds, it's actually extremely rare... especially on diesels. Diesel exhaust temps are typically lower than gasoline counterparts, and simply from that standpoint are far less susceptible to turbo coking. Just not as much heat to begin with.

On top of that, engine oil has changed over the years, as well as turbo design, oil passages, types of metal and materials used, etc. There's a combination of technology advances that have made turbo coking a rarity and something that most people don't even know about these days.

In the end, does it hurt to let your truck idle for a minute or two after a hard pull? Absolutely nothing wrong with doing that. But if you shut it off hot, you're also not really doing any harm either. Happens all the time.

I'm sure in some extreme case of a truck constantly being run hard and shut off immediately, over years may end up with a failed turbo due to coking. However, for the normal PSD driver, it doesn't happen and it's not going to happen anytime soon. That's why there aren't any posts on the forums about turbos failing due to coking on PowerStrokes.

 

Great information! Thanks for taking the time to explain.

 

My take on this is quite simple......when one pulls off the highway or freeway, drives around for a couple of blocks, sits in line waiting for fuel, etc. all under light throttle settings, things have cooled down sufficiently to shut the engine off with no damage. When I was running the big rigs, I used this method for a couple million miles, and never had a turbo go out!!

 

When towing my camper I typically leave the truck running until the camper is in it's spot, chocked and unhooked. Normal driving or hauling I wait until the oil temp drops below 200°F, this usually takes less than a minute for normal driving or the time it takes to place the camper when towing.