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Tuesday, April 26, 2016

A Geyser of a Coolant Leak

July 22, 2015

On our final run up the channel to Juneau, I thought I smelled engine coolant.  Laurie thought she smelled something too, but we both attributed it to the passing cruise ships.  Wrong!

After we got tied up, I did a post run engine room check and look what I found

Coolant on the floor and engine pan
Coolant all over the engine
Coolant dripping from the ceiling

This one was a real geyser and blasted the whole engine room.  It didn't take long to figure out that the turbo gasket was leaking profusely.  But why?

After some consultation with PAE, the first diagnostic step was to uncouple the turbo exhaust elbow form the turbo and see whether they remained naturally aligned.  They did not, with the elbow and exhaust riser dropping freely until it bottomed out against the railing around the engine.  The exhaust structure was clearly placing a lot of weight on the turbo.

Exhaust elbow wanting to hang down well below the turbo.

The next diagnostic step was to see if the turbo mount nuts were tight, and try to tighten them up if they were not.  The top two were clearly lose, and when I tightened them, one broke right off and the other just kept turning.  Both of the top studs had pulled apart, indicating too much strain on the turbo.   The picture below is after the turbo was removed, but clearly shows the broken studs.  The top left parted just inside the manifold, and the top right parted right at the nut.  The bottom studs were intact, at least visually.

Broken turbo studs

Having just been through the repair of an engine coolant leak 10 days earlier that was clearly a warranty job, I decided to dump most of this one on PAE.  While they were arranging for parts and a custom support bracket to off-load the weight of the exhaust riser, I went ahead and removed the turbo, cleaned things up, and removed the old studs.  That last step was easier said than done.

I was able to get vice grips on the top right stud and get it out.  One of the bottom studs came out fine too, but the other one snapped right off when I gave it a little turn.  Even though it looked fine, it was clearly about to come apart just like the top studs.  Fortunately there was enough of a stub to grab hold of and I was able to get it out.  That left the upper left stud where there was no choice but to drill and use an extractor.  If you have never seen an extractor, it's basically a reverse threaded screw.  Once there is a hole drilled in the stud, you screw in the extractor counter clockwise (the unscrew direction) and it bites into the stud hole, eventually getting in tight enough that it starts to unscrew the stud itself.  They can be tricky, but usually work if you are careful.  If you are having a really bad day, the top of the extractor will break off in the hole.   Fortunately this one came out OK.

A parts kit came via air the next day including a new gasket, studs, nuts, and a handful of other gaskets.  Casey from PAE arrived the next day and started putting it all back together, including a new support strut for the exhaust as seen below.

New exhaust support strut

The strut bolts to the engine block on one end, and to a bracket on the exhaust flange on the other end.  There is a threaded rod in the middle that allows for adjustment such that the strut is carrying all the weight of the exhaust, not the turbo.


Bracket tying strut to exhaust flange to weight of carry exhaust riser
With this, we were back in action...

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