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DrededSS
10-12-2011, 11:27
Well my 04.5 has given up the fight. I bought it at 60k miles 5 years ago, immediately took it to my driveway and added intake/exhaust/tune. It's spent a lot of its time tied to heavy trailers. I blew out the intercooler while in the Ozarks last year while towing 10k lbs. I had to keep it in 3rd and 4th to keep the EGTs at bay. I noticed a couple months ago during the Texas drought that the EGTs were starting to get higher than they should while unloaded and on the lowest EFI tune. It started dirtying the oil faster and has blow-by. While pulling the allison last weekend, I could use 2 fingers on the wrench to turn the engine over at the crank.

Ordered a new GM LLY on Monday, and it was at the dealership on Tuesday. My friend and I will be swapping in the new longblock next weekend. Should be time consuming since we have to swap over all the accessories and other little items.

I can't blame any of this on the truck since it was my modifications and driving style that caused this. Looking forward to basically a new truck after all this!
rapidoxidationman
10-12-2011, 11:47
What was the ending mileage for the engine?
DrededSS
10-12-2011, 14:03
160k. I'm sure it would have lasted a lot longer if I had left the stock turbo on there. Plus something happened with the original owner that I didn't discover until last year when the intercooler let go. He apparently also had an intercooler problem, but instead of replacing it, he coated the inside of the coupler with silicone and shoved it onto the cooler.
More Power
10-19-2011, 10:14
Seems other LLY owners have had problems with the intercooler hoses blowing under boost. I don't remember the details, but GM did offer a redesigned set of aluminum pipes (ducts), hoses, and clamps to help solve that problem.

It appears you think the rings are worn, which resulted in low compression. I've seen the inside of really high mileage engines that showed little cylinder/ring wear. The upper portion of these cylinders were induction hardened at the DMAX factory, which was designed to resist cylinder wear.

We did a story a couple years ago about a 750,000 mile LLY that was used as a commercial RV delivery truck... Read more here:
http://www.thedieselpage.com/duramax/750kduramaxc.htm

Jim