Coolant Leak from EGR Cooler Fitting with Motor Block

[tariqzai]

Hi there, I have an issue that has already cost me thousands of buck but still no fix. I will really appreciate your expert opinion, it's a freightliner Cascadia with ISX CM 871, 500hp. a month a go Coolant started leaking from the Fitting that hooks up EGR cooler coolant line to the Engine Block on lower back part of passenger side of engine (see pic). Mechanic took the lower fitting from engine block and replaced O rings but did't fix the problem, he then replaced the EGR cooler, it did work for about 10k miles but started leaking again, 2-3 gallons a day now. What should I do now, get O rings again, new fitting that mounts to the block or new cooler? please advise.

[Nilao]

Being a new egr cooler I would suspect the egr to block tube to have some imperfections in it. I would pull that section of pipe out and give it a thorough inspection. It's also possible the o-ring got pinched during assembly and nicked the mating surface. I would also ask that you make sure you're not building excess pressure in the cooling system as that could cause a leak also.

[Rawze]

?Those bushings between the EGR cooler and the pipe that attaches to the block come with 0-rings. He should have replaced the bushings and polished all the rust out of the components to be re-used. -- it simply looks like someone did a piss-poor job if you ask me.

Also,m Like mentioned above... Check to ensure you aren't getting pressure buildup in the coolant system from the engine while under load. You could have a dropped liner etc. causing excess pressure in the coolant system when engine is put under heavy torque.

[Signature620]

The o rings keep leaking because that expansion piece in between the cooler and the elbow is on a horrendous angle. It should be near straight. For some reason the EGR cooler is sticking out too far from the block.

[in2trux]

That elbow looks like it was damaged and poorly repaired . A new one should be a simple DIY project.

[Rawze]

(01-25-2017 )Signature620 Wrote:  The o rings keep leaking because that expansion piece in between the cooler and the elbow is on a horrendous angle. It should be near straight. For some reason the EGR cooler is sticking out too far from the block.

Nice catch...

Didn't notice that in the pic until you pointed it out.

I have seen that before too. EGR cooler not mounted improperly. It usually also causes them to crack and fail after a while too.

Also, I hope it is not an after-market EGR cooler, but OEM. Otherwise he will eventually be looking at a failed engine too.

Related reading..
http://rawze.com/forums/showthread.php?t...33#pid2233

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failed engine from after-market egr cooler..
http://rawze.com/forums/showthread.php?t...02#pid2802
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[tariqzai]

Thank you Nilo, Signature620, In2trux and Rawze for your expert advice, you are right the elbow looks like not perfectly straight, it was the case with the previous EGR as well, for some reason EGR and elbow were not strait, don't know if it's the EGR or its the Elbow, when mechanic replaced the EGR it looked perfectly straight but now its again angled. I will replace the elbow, O rings and bushing since these are not that expensive, will update you if it fixed the issue. I assume the engine is not over pressurizing the cooling system as I don't see anything leaking from reservoir, I have a kw with same engine and it has the over pressurizing issue that I am dealing with last 75k miles but this one has no signs of pushing water.