Heat Exchanger - Making a good Seal

[upthesolent]

Morning.

I have a Vetus M2 C5 twin diesel engine and just cleaned out my heat exchanger after 18 months since last done. However, I notice there is corrosion (pitting) at the bottom of the casing where the end caps fits and the seal sits. I never had a leak as such those 18 months, but guess there has been a small amount of "weeping".

Now fitted back together using a new O ring (greased as per instructions) I have a most definate leak, even more so once engine is up to running heat.

Does anyone have ideas on how I can fix this on a budget, say for example with a special kind of sealant which I can put the O ring in with and will allow for the pitting, or perhaps another kind of rubber seal which can cope with the corrosion.

Long term I dread to think. Being a marinised Mitsubishi I am guessing the whole heat exchanger housing can be replaced (easily?), but I know that at the moment this will be completely way above my current financial resources.

Thanks in advance.

 

[duncanmack]

Fit a thicker "0" ring to both ends. It worked on mine.

 

[rob2]

All the marinisation parts can be sourced through Vetus, although if you know the base engine type, engine spares may be cheaper elsewhere. My only suggestion would be to clean the surface really carefully and fill the pitting with plastic metal. In my youth, Araldite would stick to anything and make a permanent repair though of late many modern formulations are not so effective! If you can effectively repair the surface, then grease it before fiting the o-ring to help prevent attack by salt.

Rob.

 

[MYStargazer]

I don't know how yours are designed, but it's sometimes possible to use lapping paste without the rubber seal, then clean and refit with the seal.

 

[upthesolent]

Many thanks for the replies so far.

 

[sailorman]

The O ring is designed to seal & keep the cap away from the H/E body s differing metals are not on direct contact. Do not over tighten the end caps so you get metal to metal contact

 

[superheat6k]

Smother the o ring and surface in Loctite 577.

If this won't seal it, then any cheap repair is unlikely to work, but you might be able to repair the pits with epoxy adhesive, giving the o ring a smooth surface to sit on.

 

[upthesolent]

An update then to my query. I decided to try the plastic metal route and bought a tube of Plastic Padding Chemical Metal for a fiver as thought it best to try and repair the problem rather than work around it.

Brought my little 1 Kw fan heater down to the boat and ran it to warm up the heat exchanger casing so that I had a working temperature for the paste to work. The repaired job wasn't a pretty sight and I still had doubts before I put it all together again. Starting the engine.......no leak, but with being tied alongside the pontoon put the boat into gear and ran on half revs to work the engine up to running temperature.

NO LEAK!

Once again, thanks to all