Cleaning a heat exchanger? Should I?

• Sep 24, 2017

• #1

mnm99

Well-Known Member

Oct 2, 2015

2,447

Long Island

Boat Info

2004 340 SeaRay Sundancer

Engines

Twin 8.1 Merc

This winter after I winterize I want to do some maintenance. I want to take a look at my heat exchanger. The boat has been a fresh water boat for it whole life (2004) except for the last 2 in salt. First question is should I even bother taking a look at the exchanger and the oil, trans coolers? If I do look at the exchanger is it as simple as the one bolt on the side to take a look? Would I need a new gasket? I don't want problems with leaks in the spring. Thanks

 

• Sep 25, 2017

• #2

juggernaut1

Well-Known Member

Apr 19, 2015

1,152

Perth, Western Australia

Boat Info

Boatless - sold Searay 38 Sundancer

Engines

8.1’s

Trans coolers would be the easiest to inspect - remove the hoses and inspect - and are first in line in the raw water circulation system.

Manual says to discard the gasket and o-ring on the heat exchanger when inspecting/cleaning (every 2 years IIRC). I guess you could try your luck and apply the Perfect Seal to both sides of the gasket (per the manual) and see if there are any leaks after assembly and running.

 

• Sep 25, 2017

• #3

kap2

Active Member

Oct 28, 2013

203

Rhode Island

Boat Info

370 Sundancer 1998

Engines

Twin 7.4L Mercruiser V-drive

IMO - the heat exchanger inspection is a good idea and go with new gaskets and o-rings. Its short $$ knowing the system is clean and leak free. As a recommended maintenance item, taking it apart every 2 years, I would not go with Perfect Seal on the used gaskets and I don't think it would work well on the o-ring.

 

• Sep 25, 2017

• #4

Stee6043

Well-Known Member

Jun 1, 2015

6,734

West Michigan

Boat Info

1997 Sundancer 400

Engines

7.4L Gassers

Trans coolers are cheap! If you're going through the trouble of removing them I'd personally just replace them. $300 job to do both sides, +/-. Cheap insurance.

I have no opinion on the oil coolers...I haven't done those yet.

 

• Sep 27, 2017

• #5

J

John bouy

Member

Aug 2, 2014

42

British columbia

Boat Info

1992 300 sundancer

Engines

Twin 1994 4.3 litre mercruisers alpha 1 gen 2

Good idea to send them in to get cleaned and pressure tested. They can find/fix any pinhole leaks that you'd otherwise be unaware of. Relatively cheap to have done.

 

• Sep 27, 2017

• #6

trdehmer

Member

Jul 29, 2009

186

Lake Minnetonka, MN

Boat Info

2003 280 DA

Engines

Single 496 MAG

If your heat exchanger is similar to what is on my 280 Sundancer, I clean it out once or twice a year (tiny pebbles and Zebra Mussels get in it) and I have been re-using the o-ring and gasket over and over again w/o any issue, and can't imagine I'd ever have an issue unless they got real hot and it destroyed the rubber...

I use a coat hanger through each hole to push anything through them that might be a little stuck - push from one side to the next.

I'm in fresh water however...