Now, before anyone busts me, I did the search and maybe didn't have the right keyword or whatever, but here's my problem: I read somewhere around here that before shutting down the engine, you should wait for the EGT's to drop below 300 F. This seems a bit much to me as I will be spending much of my life watching these temps slowly descend. Believe me, I've tried it, the temps get down to about 330 and then it's like watching the grass grow. Just how important is this? I'm not talking a long pull thru the mountains of New Hampshire or something here. I mean a trip to Lowe's or the beach or wherever. I don't want to damage any of the intricate parts of this fine machine, but I have a life to live. What's an acceptable temp to shut my truck off and get on with things without concern about the turbo being too hot?

I let mine get down to 250° pre-turbo before shutting down, which usually takes no longer than 4 minutes--usually about 2 minutes.

If you don't want to wait get a turbo-timer. I really like mine.

coyotekid does your turbo timer use a clock to time the motor shutdown or does it run of a pyrometer? I wonder if you can get one that uses a pyrometer lead.

350 is pretty safe

Mine is based on time, but there are units available that work off a pyro lead. Isspro makes one of these types of units.

I had never thought about this subject for light duty diesel truck but in Heavy duty truck, you should wait several minutes before shutting the tuck down to cool the oil for the turbo bearing. If the turbo is hot, the oil will cook inside the turbo and ruin the bearing.

With Banks system, there pyro shows below 350 is o.k. to shut down...with opened up intake and exhaust, didn't seem to take more then a min. or two to achieve this.

i usually saw coking on genset's that tripped and shut-down, if you drive thru town the engine should cool down. should look at water temp. also as turbo is water cooled, heat will dissipate some thru water. i would think if you surveyed, would be more likely with drag racing or tractor pulling where engine is at full thermo generation and shutting down right after run.

In the big truck engines Caterpillar says about 3 minutes of "cool-down" time is sufficient. With my duramax unless I've been pulling it hard I just let it run for a minute or two (I don't time it) and shut it down. It's not a huge deal, just give it a little time and you'll be fine.

Seems to me if it really was that critical then the big three would program the computer to run the truck even after you killed the key and the computer would shut down the engine when it is "safe". They must not be concerned, they don't even bother to measure the temps anywhere near the turbo.

Apparently modern turbos, both car and truck, seem fine with unexpected shutdowns. Maybe in the old days with lesser materials, less precise machining, and inferior lubricants this was an issue but there are loads of cars and trucks out there doing fine without "turbo timers". I have only ever personally known one turbo to ever fail, a 2004 D-brand 5.9 with 113,000 very hard abusive miles on it, so turbo reliability seems high to me.

Just think of how many trannies you have seen fail compared to turbos.

My .02 (still not tax deductible, sorry!)

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I've had more turbos fail than trannies..... but then again, I'm Special....HAR HAR HAR!

My .02 (still not tax deductible, sorry!).

So, I can expect an audit?:cool:

So, I can expect an audit?:cool:

Sup to you what to report to the Infernal Revenue Service :cool: :deal: :lol: :sheephump :muahaha: :help:

The most I have ever heard is letting them cool down for 5 mins. for work, but lots of guys shut them down when there phone rings from WOT.

Even if the turbo is allowed to cool down for five minutes, isn't only the exhaust gas cool, the turbo itself (the metal) is still very hot and could it still cause damage?

Mine doesn't go below 400 degrees.

I also think if it were a big problem dont you think the big 3 would tell you this in the owners manual or have the trucks with a cool down timer? After all if it was a problem and was going to cost them alot of money in repair they would install this item or tell you in the owners manual that cool down is nessary.

Use a good synthetic oil and let it cool down to 350 and you'll be fine. Coking is a problem withhot turbo's and I have seen quite a few fail due to this, synthetic oil does wonders in that dept. plus it's cheap ins.

I'll agree that it's potentially overkill. But, I'd like to see this thing last, and in my circle of friends/family, I'm know for being anal about mechanical things. Other stuff, I could really give a **** about. :)

I've been wondering about this also. Where can I buy a turbo timer?

I would kind of like one as well. It would also be nice if it had a remote start on it.

Modern turbos on ight duty vehicles should be fine without a cooldown period. Like others have said, the manufacturer would have prescribed a cooldown period, or have engineered in a turbo timer if it was needed.

I don't know about our truck, but I know my former Subaru WRX's turbo was cooled by oil and coolant, and when the engine was shut down there was a cycle of evaporation that allowed the turbo to cool down just fine.

I wouldn't waste money on a turbo timer for this truck. If the turbo melts within 100K miles, we can just have it replaced under warranty. After that, we can pretty much be sure that a turbo is good for 100K of driving.

Also I think there is a difference between shutting down right after full/heavy load on engine and shutting down after slowing to driveway, turning in, shifting to park...well you get the idea. What I am getting at is how many people hit their driveway at 75MPH and turning the key off.

Me, but I have to use the e-brake to get turned around as I'm coming in. :ro)

Crud -- I never do this. Something I should worry about?

LB7 only, I believe a "Lite" throttle period achieves the same as an Idle period.

When we used to Cool Down the turbo with Only oil it took a while for the oil to carry away the heat from the bearings.

With the LB7 turbo the bearings are cooled by oil and the Whole Turbo is cooled with engine coolant, a new world to me.

I do not know if the LLY turbo is "Water Cooled", if so it would be the same.

If you have been working it hard, cool it down, else just drive it.

IMO.

Idahofox

If we used the theory that engineers were all-knowing wise men, there would be no need to modify anything on our trucks.

If we use this reasoning:

Beefed up trannies are a waste of money.

Transmission coolers are for the birds.

Computer performance modules/tuners are no good.

I agree that they're probably not absolutely necessary but blind faith in automotive engineers isn't smart, either!

If we used the theory that engineers were all-knowing wise men, there would be no need to modify anything on our trucks.

If we use this reasoning:

Beefed up trannies are a waste of money.

Transmission coolers are for the birds.

Computer performance modules/tuners are no good.

I agree that they're probably not absolutely necessary but blind faith in automotive engineers isn't smart, either!


I think pretty much everyone with a stock truck would say YES, all that stuff is a waste of money, since the truck does its job and functions correctly the way it is.

To me the question brought out by this thread seems to be is there any benefit provided to the turbo by a "turbo timer" or even a "cool down period".

The are plenty of products and practices out in this world that are a waste of time and especially money but yet the producer will preach you just have to have. For example, the oil change industry tries real hard to make you believe that you need to change your oil every 3 months or 3,000 miles. They constantly pound away that idea. Of course they do, they want you coming back spending money like clockwork. I always laughed at the time limit part of thier pitch.

My new Honda Accord Hybrid says change its oil every 7500 miles. Who is right between Honda and Jiffy Lube? In the real world I have gone 10k or even 12k or more with no issues on vehicles that run up 150,000 miles in a year. If I listened to Jiffy Lube I would be sitting in their shop every 8 or 9 days getting my oil changed, and apparently oil expires after 90 days. That would be a large investment in time especially, and a healthy chunk of money.

All I want is some real world evidence, data if you will, that my turbo is damaged appreciably under normal usage by not allowing it a cool down period, and then I would want to know why GM didn't add it to the endless list of warnings in the owners manual or the diesel supplement that came with the truck.

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I'm an Ol' OTR driver (Trucker). My opinion on "Cooling Down a Turbo" has been changing slower than the "Design of New Turbos". That said, with normal day - day driving, I do not believe "Cooling Down" is Necessary.

But Hey, "If it feels Good, Do it".

Where is this Going ?

Idahofox

Nowhere. Just boils down to preference and peace of mind I guess.

sounds about right.
still want a remote start tho, so i might as well get one with a turbo cool down on it.:rolleyes:

Usually, the 25 MPH drive through my neighborhood acts as my cooldown period. However, on some Texas state highways, I can be cruising along at 75, and 20 seconds later, be parked at the fuel pump (some stations are right alongside the road). In those cases, I give it a minute or 2 to cool off, before shutting down.

We do have excellent roads don't we?

My egt's don't get much below 400 on my LLY, especially with air con on. I don't think the LLY turbo has water cooling like the LB7 does. If you want a turbo timer, you might as well get a remote start. My Viper 160XV has a shutdown timer that lets the truck idle for a set amount of time and then shuts it down. It kills two birds with one stone and is about the same price as a turbo timer. I am going to synthetic at 10,000 miles for piece of mind.