Cummins 8.3's loosing coolant tru exhaust ?

R

Robski97

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Guys,
Ive been loosing coolant for 2 years now . Slowly at first but now every 10 hrs I have to add. Its definitely not in the bilge , not in oil, so it has to be going out the exhaust. Where on the motor would this happen ?

Rob
 
The heat exchanger. The long tube near the top.
 
If the exhaust manifold is cooled by anti-freeze, the joint between the manifold and riser is likely leaking. also possible head gasket leak...if diesels are anything like gassers.
 
quote:
Originally posted by pdecat

The heat exchanger. The long tube near the top.

Click to expand...


+1. That's the first place to look.

Bob
 
"Ive been loosing coolant for 2 years now . Slowly at first but now every 10 hrs I have to add."

The banjo bolt fitting at the bottom of that engines turbo is notorious for leaking and hard to correct even with a new bolt and copper washer. Please check that banjo fitting and see if that is the spot.

Hope this helps
 
I have no GREEN stains anywhere on motor to show its leaking . BILGE is spotless Smitty. The smell of the coolant though is very heavy . I will triple check under the turbo. But ive been pretty meticulous

Rob
 
Call Merc didn't they build that motor with Cummins?
I'm joking Rob, I'm thinking it's going out the exhaust being burnt showing no traces only the smell?
My uneducated guess would be the heat exchanger is compromised.
Bill
 
Hi Rob,

"I have no GREEN stains anywhere on motor to show its leaking . BILGE is spotless Smitty. The smell of the coolant though is very heavy . I will triple check under the turbo. But ive been pretty meticulous"

It's been a couple of years but I have done a few of them and they were hard to detect and worse to try and toque down with the space available.
My second guess would be the connecting gaskets between the manifold and the turbo base as the coolant passages are between the two and can pass to the exhaust as well.

Perhaps reading some of the tips on Tony Athens site might help as I have not been on there either recently - sbmar(dot)com.

Hope this helps - Ron
 
what the others said plus I just read on another site that the turbo itself could be suspect..which series engines?
 
8.3 500 hp

I posted on The DIESEL forum site . No replays yet.

Rob
 
get a pressure tester from auto supply store, fits on the radiator cap fitting on the expansion tank. isolate the heat exchanger with plugs on the line in and out of the heat exchanger as others have suggested before pulling it out of the boat. run a pressure test and see if that is the source of the leak.

as an alternative you can also pull the heat exchanger and after coolers and have them ultra sonically cleaned. google tony Athens after cooler on specifics on the later, you will find it helpful.
 
Sounds like the turbo is mounted on top of the exhaust manifold. If there is a gasket that seals off the coolant between the turbo/manifold joint, like smitty 477(Ron) was kind enuff to explain... which would be the weak link like in gassers.

The second weakest link would be a leak between the raw water and coolant in the heat exchanger like Vic said. If there's a way to view the cooling tubes, pressurizing the engine/coolant will show the leak as a dribble or spray in the heat exchanger.
 
Remove the end cap from the exchanger while pressure testing to look for coolant where only sea water should be
 
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