Leaking Heat exchanger end caps

[Steve Thomo]

Hi I have a 330HP 2003 cummins marine engine serial number 46276536.
Is it posible if to give me a step by step instructions on how to drain etc to remove the end caps and replace the gasket and washer.
Then what needs to be done if anything to fill the system again prior to starting the engine after the seals have been changed.
Regards Thomo

Topic

[David Amble]

I use a good boat trailer wheel bearing grease on bolts around water systems and a Moly grease on high temperature bolts. Again available at Supercheap or any reasonable auto shop.

[Steve Thomo]

Hi David thanks for your reply.
Do I need to put anything on the bolt itself?

[David Amble]

Yes, difficult to find Rectorseal in Australia. I ended up buying some through Amazon and even then it came in from the US. Final cost delivered to my door was A$25.17 for a 1/4 pint tin.

As for end caps on 6BT/A heat exchangers and also Onan heat exchangers, I prefer to fit the end caps and gaskets clean and dry; definitely do NOT over tighten and make sure the small ring goes on the bolt between the end cap and the gasket. Never had a leak and usually get multiple uses out of the gaskets if removed carefully.

If you want to use something on the gasket and can’t get Rectorseal, a smear of red rubber grease works fine; readily available at Supercheap Auto stores.

[Rob Schepis]

Steve Thomo wrote:

Sorry Rob I called you Bob by mistake!

That’s the norm. Back in the “old days” when we used to shake hands and greet someone it would usually go like this;

Me: Hi, I’m Rob
Them: Hi Bob, nice to meet you

The Rob to Bob thing was always more common with older folks, not much at all when the person was younger than I so I guess eventually it will become a thing of the past!

[Steve Thomo]

Sorry Rob I called you Bob by mistake!

[Steve Thomo]

Hi Bob I think I have found somewhere to buy Rectroseal 5.
Is it used on the gasket it self both sides or on the bolt thread?
Regards

[Rob Schepis]

Maybe one of our Australia members will chime in as to the RS5 locally.
As an alternative – See attached.
I use this one on threaded nylon water fittings, also soft setting and a nice consistency….

[Steve Thomo]

Hi Rob thankyou for your reply. Is there an alternative that you recommend to use other than Rectorseal 5.
I can not seem to find that here in Australia.
Regards Steve

[Rob Schepis]

Do you understand what it is you are draining from the heat exchanger to remove the end caps? It’s just the raw water – not the coolant. Simply pull the zinc. The rest will dribble out when the cap is removed. But if your caps have been flattened over time the new gasket will not do as it should. Have you done any searching on the site? Here’s a couple handy links:

https://www.sbmar.com/community/topic/heat-exchanger-flat-end-cap-fix/

https://www.sbmar.com/community/topic/6bta-heat-exchanger-service/

[Author]

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