Duramax Diesels Forum Truck of the Week
Old 01-11-2019, 01:36 PM
MJfarmer MJfarmer is offline
Join Date: Jan 2019
Posts: 2
Default Coolant Leak Driver Rear

Hey guys,

I recently got my dad 2007 duramax running after 3 years. It was his daily driver (465,000K on it) and one day it wouldn't stay running. We pulled it into the shop, checked all the fuel lines, and filter housing, all were fine. Ended up doing the injector pump on some bad advice from a GM service manager, $2300 later same problem. While we were changing the pump we also deleted the EGR cooler. We left the coolant out and the truck still wouldnt stay running longer then 3 seconds. Being pissed off and working on this truck for over a month, we pulled it outside and it sat there for 3 years.

Well this winter we pulled it in, and turns out a green wire under the fuse box in the engine bay had been chewed off clean by a mouse, fixed the wire and truck runs like a top! Filled it up with coolant and took it for a drive.

Truck has a slight drip from the rear driver side of the engine, up near the oil cooler. I pulled the oil cooler off and did the seals in everything. I just got it back together and same problem. I was very careful to not damage or pinch any seals. When the trucks cold or running it just drips. but when its shut off and cooling down it is more of stream. I cannot for the life of me figure out where its coming from. But here is my best guess

The rad hose doesnt get hard, the coolant isnt dirty, the oil is clean, but I havent had the tools to pressurize the cooling system yet. But what advice can you give me to test that next?

I have read that the bell housing plate has coolant pass through it and they can crack and leak. With the amount of kms on this truck it is a high possibly it could be that too?

I would love to get this truck out of the shop and get it running for him again, open to any ideas to check for!

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Old 01-11-2019, 03:41 PM
MJfarmer MJfarmer is offline
Join Date: Jan 2019
Posts: 2

Okay I got it figured out. The small 3/8s coolant line that feeds the turbo had a cut underneath the factory hose clamp. Everytime it would get hot and pressured it would spew out until it cooled down. I literally couldnt see the coolant coming out of it. I just removed the line om advice from someone else and sure enough I could see it. 20 minutes running and not a drop of antifreeze on the cement now. Im glad I did the oil cooler seals though as its never been touched on this truck.

My advice for anyone is START WITH THE SMALL LINE! Even if you cant see it leaking remove it and replace it. Very easy to do and much cheaper. After 3 years this truck is finally running and out of the shop! Thanks to everyone on here that has posted issues before. I wouldnt of found the broken wire under the fuse box if it wasnt for forums like these!
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Old 01-11-2019, 04:25 PM
TheBac's Avatar
TheBac TheBac is offline
Why do I keep doing this?

Join Date: Apr 2008
Location: Mid Michigan
Posts: 12,324


Always check the simple stuff first. Glad you got it repaired.
"BBT" -- 2003 GMC CC/SB 4x4 12.14@111.15
"The Cruzer" -- 2014 Chevy Cruze Diesel -- the DD
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