Chevy and GMC Duramax Diesel Forum banner
  • Hey Everyone! Enter your ride HERE to be a part of this months Ride of the Month Challenge!

1 - 20 of 54 Posts

·
Registered
Joined
·
360 Posts
Discussion Starter · #1 ·
Had a large coolant leak spewing everywhere from the rear of the engine a few weeks ago, took it to a shop in front of my work and they found a cracked heater hose and replaced. It was still leaking so I took it back. They found a small leak at the rear of the turbo inlet where there is a copper washer basically..? replaced that and it is still leaking. Mainly when it sits in my driveway overnight, during the day at work sitting flat it doesn't seem to do it.

It is definitely the rear passenger side and coming either from up top or middle of the engine. Coolant hose is soft in the mornings, doesn't seem to be a head gasket issue at this point.

Any advice where to look on the right rear side specifically? I'm hoping for another hose of some sort that has worn out after 200,000 miles.

Thanks!
 

·
Registered
Joined
·
1,587 Posts
rear pass side of motor- on the rear adapter plate there is a coolant plate. they have been know to randomly start leaking. its actually under your downpipe.

only way I found mine was to pressurize my cooling system and search for the leak.
 

·
Registered
Joined
·
360 Posts
Discussion Starter · #3 ·
rear pass side of motor- on the rear adapter plate there is a coolant plate. they have been know to randomly start leaking. its actually under your downpipe.

only way I found mine was to pressurize my cooling system and search for the leak.
Ok, thank you for the post. I will search under there some more. What is the fix for the coolant plate? Just a seal of some sort?
 

·
Registered
Joined
·
1,587 Posts
im pretty sure there is just a metal gasket under there.

Once I removed my plate, I filed it to ensure it was flat. put a new gasket on with some gasket sealant.

If you can try to look down into the valley of the motor around the turbo, see if you see any coolant laying in the valley. If you cant see any in the valley, the only connections on the rear side of the motor are the heater hoses at the firewall (into the egr cooler if you still have it)

just noticed too you said it was a large leak. many ppl have said in the past when that plate gasket goes it dumps tons of coolant
 

·
Registered
Joined
·
360 Posts
Discussion Starter · #5 ·
im pretty sure there is just a metal gasket under there.

Once I removed my plate, I filed it to ensure it was flat. put a new gasket on with some gasket sealant.

If you can try to look down into the valley of the motor around the turbo, see if you see any coolant laying in the valley. If you cant see any in the valley, the only connections on the rear side of the motor are the heater hoses at the firewall (into the egr cooler if you still have it)

just noticed too you said it was a large leak. many ppl have said in the past when that plate gasket goes it dumps tons of coolant
I will look in the valley there by the turbo. This should be taken care of with the work the shop did. I think the plate is the next place to start. I do still have the egr cooler and everything stock on the motor to my knowledge.

It seems to leak worse when parked on my slanted driveway...at work on the flat ground during the day I do not see any drips really. overnight in my driveway there will be about a 2' circular patch where it dripped.
 

·
Registered
Joined
·
360 Posts
Discussion Starter · #6 ·
well guys...I changed my fuel filter this weekend and I searched high and low for this leak without success. I let it sit again overnight without plugging it in and came out in the am to find the upper radiator hose basically hard. From everything I have read this would absolutely point at the head gasket..I did the same thing by checking it this am and hard again. Without knowing exactly what is going on here I would say it has started to go at the backside of the motor because when it sits in my driveway (which has a nice incline to it) frontwards it leaks on the ground overnight. I backed it in the last two nights and basically no visible leaks on the cement.

Head gasket at a diesel shop probably going to run minimum $4k?? I guess I will have to get it in and hopefully they can confirm for sure if that is what it is. Any advice from here appreciated.

Thx
Kyle
 

·
Registered
Joined
·
385 Posts
Have the cooling system pressure tested before you jump to any conclusions. These duramax's are a pain in the ass to see anything under the intake/egr/turbo/etc. Have it pressure tested and they can tell you where it's leaking. They can also tell if it's a head gasket, usually drop something into the coolant and test for combustion gases in the coolant. After a good drive does your overflow tank bubble?
 

·
Registered
Joined
·
1,587 Posts
Did you ever pressurize the system?

I would be trying to rule out every other possibility before jumping to head gaskets
 

·
Registered
Joined
·
360 Posts
Discussion Starter · #9 ·
Getting it into Gem State Diesel here locally. I've looked up reviews and all I could find and they seem to be a reputable shop. The guy on the phone was helpful and nice and set up an appt but they are a week out.

He says they use same techniques and diagnostics as going to a dealer. Maybe that helps with confidence? Idk haha.

Thanks for the replies guys. Hopefully I can figure this out soon. If it is a head gasket I will have likely have a Duramax for sale that needs a head gasket.
 

·
Registered
Joined
·
385 Posts
No problem man! Hopefully it isn't the HG's. Should be fine, pressurizing the coolant system can be done by anyone as long as they have the machine. Dealer here quoted me 65$ to pressure test a coolant system. Just for comparison.
 

·
Premium Member
Joined
·
26,484 Posts

·
Premium Member
Joined
·
26,484 Posts
I guess, $60 (you own it) vs $65 for someone else to test it (plus your time to/fro to drop off). Although, they should test for free if they do the hose repair/replacement. How many have bought the socket for hub replacement...never to do it again? Or not.

Roll of the dice, just an option. It's not like you'll never have another one of the many little small hoses blow in the future.
Or, the wifey/GF's car springs a leak.
 

·
Registered
Joined
·
385 Posts
Oh I know! I wasn't talking down about your idea. I said it might be a good investment if you are going to be checking it again, or checking other trucks in the future. Sorry if that came across wrong! Was also curious how it worked, screw it onto the coolant overflow tank and pressurize to whatever it says on the gauge? Not sure if you had used one
 

·
Registered
Joined
·
360 Posts
Discussion Starter · #15 ·
I have heard of testing yourself for sure. When I was in the last shop that fixed my leaking hoses they had it on a tester that was pressurized through the top of the overflow tank. At that time it was holding pressure well. That is why at this point I am going to let the pros take a look at it.
 

·
Registered
Joined
·
1,587 Posts
if you have an air compressor you can easily rig up a method to pressurize your system for free. that's how I did mine
 

·
Premium Member
Joined
·
26,484 Posts
...Was also curious how it worked, screw it onto the coolant overflow tank and pressurize to whatever it says on the gauge?
Yes, you remove the surge tank cap (or radiator cap if you have an overflow tank) and add 15-20psi of pressure and see if it holds or has an obvious gusher leaking.

As PJ mentioned, you could also make your own with a few plumbing parts from Lowes/HD...coupler, hose clamps, reducer bushing, some nipples, a brass Tee, a gauge and a tank fill valve. Double duty for testing fuel system for leaks too.

 

·
Premium Member
Joined
·
26,484 Posts
The pic is rigged for the fuel tank fill nozzle, but the same principle works, securing on the threads for the cap. Or, you can also drill and tap on old tank cap for a threaded nipple too. It's not any mega-pressure, you're only matching the same 15psi as the cap.
 
  • Like
Reactions: trevore

·
Registered
Joined
·
360 Posts
Discussion Starter · #20 ·
Called Big Twin here in Boise and they quoted about half the price to run diagnostic on it. They are a reputable shop here locally so I'm going to take it in to them. I described the upper rad. hose and he said without a doubt it is a head gasket...! to do it right (not sure what that entails) $5200 OUCH!!!!!!

I will know for sure beginning of next week but I will need to figure out a fair price for a LBZ short bed crew cab with 200k on the clock with possible blown head gasket. I see duramax's for sale locally all over the board.
 
1 - 20 of 54 Posts
Top