Heat exchanger end gasket

[Harmon]

I replaced what may have been an original end gasket on my star engine because it had a weep going on. Its an OEM mercruiser part. The issue I have now it leaks worse than the weep. Ive tightened the bolt all the way with a little apprehension since its a brass or bronze material and it got worse. It ran down directly to the water pump pully and made the belt slip causing an over heat. Visual inspection seems solid, no cracks, Im thinking a warp, maybe in end cap?

 

[Air O'Nautical]

It’s probably coming apart at the seams. You tighten the bolt that pulled the joint of the inner and outer casing made it drip worse.
It’s about a 10yr throwaway item.
I recommend..
https://lencoheatexchangers.com/
I’ve used them several times for several different engines for heat exchangers, oil coolers, trans coolers. Nice people with quality products.

You could take to a radiator shop to repair but, IMHO it’s beyond it’s life limit anyway.

 

[techmitch]

I replaced what may have been an original end gasket on my star engine because it had a weep going on. Its an OEM mercruiser part. The issue I have now it leaks worse than the weep. Ive tightened the bolt all the way with a little apprehension since its a brass or bronze material and it got worse. It ran down directly to the water pump pully and made the belt slip causing an over heat. Visual inspection seems solid, no cracks, Im thinking a warp, maybe in end cap?

Here's another source https://www.mrcool.us/

 

[Todd320]

Wow, Merc is proud of their heat exchangers. 2240$ vs 795$ from Lenco. Is there any justification for that, materials, longevity? Oil coolers are not as bad, 380 vs 160, but still. Mine are 13 years old and seem to work great, for 1600+320, for all engines seems reasonable, but 5300+, yikes.

 

[Harmon]

So the inner tubes are a separate piece than the outer skin, very interesting. Could I try some sealant? with the gasket to limp through the season?
Its strange the replacement gasket was much thicker than the original. Guys said it should work. I should have left it weep

 

[Air O'Nautical]

Watch the build process..
I have also bought from this place. Seems identical to Lenco but, Lenco was closer and better priced.

 

[Air O'Nautical]

You can put an automotive radiator pressure tester on your heat exchanger. If you are able to hold pressure would tell you that the internal system is sound and all you have is a raw water leak. If you cannot hold pressure in your system then you have raw water and antifreeze mixing together..not good.
If it’s just raw water....maybe a band aid could work
I check mine every year to confirm the system is good.

 

[Air O'Nautical]

No way would I pay OEM prices for a heat exchanger. No clue who the OEM supplier was?
Now, exhaust manifold/elbows I’m OEM 100% no exceptions.

 

[Air O'Nautical]

Just FYI,
Pulling the end cap, you see the raw water side of things.
Raw cooling water runs through those tubes.

 

[Harmon]

Just FYI,
Pulling the end cap, you see the raw water side of things.
Raw cooling water runs through those tubes.

Yes, thanks. I didnt know it was two separate sections, Thought it was one big unit. Like molded one piece

 

[Harmon]

You can put an automotive radiator pressure tester on your heat exchanger. If you are able to hold pressure would tell you that the internal system is sound and all you have is a raw water leak. If you cannot hold pressure in your system then you have raw water and antifreeze mixing together..not good.
If it’s just raw water....maybe a band aid could work
I check mine every year to confirm the system is good.

Its def the raw water side, Im not losing any antifreeze.

 

[Air O'Nautical]

Did you use a sealer on the gaskets?
You should, they come from the factory with sealant on the gaskets.

 

[Harmon]

I did not, what type may I ask?

 

[scoflaw]

Rubber gaskets are all I've seen, try them. No leaky

 

[Air O'Nautical]

Mercury/Quicksilver Perfect Seal. Might not be easy to find locally. Seems I put the stuff on everything.
A non-hardening pipe thread sealant will work just as well..like Real-Tuff from the plumbing section of your home store.

 

[Harmon]

It looks like the exchanger is shot, there is a rot through I didnt see initially.
Does anyone know how I could capture the antifreeze when I pull it out? How much is contained in the exchanger?

 

[Air O'Nautical]

I remove the inboard side antifreeze hose going to the exhaust manifold with a bucket below to capture it..
Really not much in the heat exchanger anyway.

 

[Harmon]

I remove the inboard side antifreeze hose going to the exhaust manifold with a bucket below to capture it..
Really not much in the heat exchanger anyway.

Thanks, Im going to pull it and have it tested

 

[uplander]

Thanks, Im going to pull it and have it tested

FYI - Another vote for Lenco. They were GREAT to deal with. Last summer right before a big planned boating trip, I began loosing antifreeze. I determined I needed a new heat exchanger. No one had one in stock. I called Lenco, they moved me into production immediately and shipped that day! (Paint was a bit smudged because the timeline was so fast......) Had new unit in 2 days from when I called them.

 

[Harmon]

Pulled it yesterday and lost more AF than I wanted. have to get some absorbing pads to clean bilge. Im having the unit tested at an old school radiator shop, the kind in an old smelly, dust, musty, cigarette scented garage with the old expert and huge vat of "neutralizer" to clean acidic cleaners off. It was quite a site.