[wms]

I do not have a actual pryo on my truck, but do have a IR heat gun. I have been using this heat gun to measure the turbo temperatures while the engine is running and cooling down. I have noticed that while the turbo inlet air pipe (pre-turbo area, passenger side)cools down pretty fast, the center section of the turbo does NOT cool very fast. After parking and with the engine idleing I can "watch" the turbo inlet pipe cool to maybe 275 degrees within approx. 2 minutes. This is in-line with what many people report when they shut the engine down.

When the inlet pipe is down to maybe 275, the center section on the turbo is STILL 400-500 degrees! I also assume that one of the turbo bearings is in this location.

It takes maybe 5-7 minutes of additional idleing to lower the center section of the turbo below 300 degrees.

Has anyone considered that the bearings of the turbo may be WAY hotter than the usual 'pre-turbo" pyro measurment location? Maybe the "pre-turbo" pipe is not a good place to measure the turbo temperature? if the bearings are what is damaged by hot shut down, maybe we should somehow measure bearing temperatures?

Just food for thought and discussion.

Y2K diesel....mostly stock.

 

[Pocket]

Yes it's hotter than the exhaust temps. It's much thicker than exhaust pipe so it's going to be nice and heat soaked. There are all sorts of varying opinions about what is best for turbo cool down. All I can do is speak from my own personal experience with my truck. I pulled my stock turbo off the truck with about 85K miles on it, and there was no signs of coking issues at all. I always shut my truck off when the pyro drops below 400 degrees. That's it, I don't really wait for it to go much lower and I've never had a problem. There are also many other people who put a lot of miles on their trucks and 1) don't have a pyro and 2) don't care about letting it idle for a few minutes to cool. How many instances of turbo coking have popped up lately?

Some people will tell you that it's terrible for our trucks to be shut down when pyro temps are above 300 degrees, others will say that it never matters what the temps are. I have my own rule of thumb for my truck, and it's been working fine. Pick your poison.

 

[arisley]

If you let the pyro cool down to 300, the bearings will be in acceptable range. That acceptable range is more than 300. History is your friend in this case, through many years of turbos, they have figured out that 300 at the manifold equals good at the bearings. That and bearing technology.