Advice on Yanmar 3QM30 exhaust

[Johnb]

I am replacing the mixing elbow on my Yanmar 3QM30F. I have all the parts and am ready to start re assembling. Would appreciate words of wisdom on:

1 How to clean/degunk the water passages in the exhaust manifold. I have it in my workshop with all the ends etc removed. Any magic medicine to wash out the passages?
2 Best anti seizing for the bolts on the manifold
3 Should I use any gasket sealer on the new gaskets - if so what.
4 The mixing elbow screws into the exhaust connector - any particular sealant recommended?

Thanks.

 

[Ken13559]

Any anti-seize compound/grease would do. If new gasket no sealant required. I usually apply anti-seize on gasket as well. Both sides. Not sure type of mixing elbow you have. But if its the U type then run some pipe tape (teflon tape) on both threads of the joint, apply anti-seize on it before screwing in tight. Do note the U side is reverse thread.

 

[kloudie1]

Raw water cooled, right? A radiator shop can boil out the manifold to clean it.. I agree with Ken on anti-seize but I wouldn't put Teflon where the temperature is that high.. http://www.autozone.com/miscellaneo...i-seize-lubricant/526814_0_0/?cmpid=PS:3:1:90
A nickel based anti-seize is perfect for that application.. Apply to both sides of the connecting threaded bushing and like Ken says, the thing has left threads on the upper.. so when ya tighten the bushing into the bottom, the top will pull tight as well.. A thin film of the anti-seize on the gasket faces and the manifold bolt threads and ya good to go !

 

[Johnb]

The engine is fresh water cooled. The exhaust manifold has sea water that has first been through the heat exchanger flowing through it. After passing through the exhaust manifold it goes by a anti siphon valve and is then injected into the mixing elbow. The mixing elbow is not a U type, and I have bought a stainless steel one from "Ben Cotton [ben@exhaustelbow.com]"

This is a repeat of the replacement I did about 6 years ago and I would like to do a better job of making the next one easier, especially preventing seizing of the fasteners.

Thank you for your replies.

 

[Ralph Johnstone]

Slather any gaskets and threads with this and they are easy to separate years down the road.

The gaskets are graphite foil on a sheet metal carrier and come off without too, too much work but the parting compound ensures they literally fall away from the surfaces after years of service.

If you're worried about the effects of high temperature on the teflon tape used at the threaded coupling (it really doesn't get hot enough to worry) use Masters Metallic thread sealant. It's lead based and has its own set of hazards. Don't rely on the parting compound to seal the coupling threads, it's NOT a sealant, just a release compound.