Stuck After cooler sleeve

[Katmand]

I have a 2001 Volvo Penta KAD 44 that is running a little hot (about 25 degrees). I'm suspecting the heat exchanger since I traced the raw water intake up to the heat exchanger and can't find and blockages, thru hull, strainer, impeller looks perfect, etc...

I can pop the top of the after cooler no problem but I can't pull out the sleeve - insert... the plug at the bottom of the exchanger seems frozen as well.

I tried using pliers to grab the lip but no luck.... any good tips on how to remove the insert?

Thanks in advance.... you guys got me this far.....

[Lepke]

I assume you operate in salt water. How long since you've flushed the salt water side? Soaking with the flushing solution you use may loosen things up. Flushing 1st would have been the better plan. Also pull the thermostat, heat in water and see what temperature it opens at.
I use rydlyme for salt water flushing and have had excellent results doing heating problems for other people. Even after professionals have flushed and fiddled. I don't have trouble with my engines because I flush on a schedule.
If you can't get it apart, try a heat exchanger/radiator shop.

[DougR]

So if you have the top of the aftercooler off and can see all the tubes, and that they are clean, why remove the core from the housing? The water flow in the AC goes down one side, across the bottom and back up the other side. Give the tubes a brushing with a thin brush if they are dirty, flush out the debris and let them be.

Do the same with the oil cooler ( I know, it's buried behind the heat exchanger).... Then take the end cap off the heat exchanger and clean the tubes there. Make sure the rubber flow divider strips are in position when you reassemble the end cap of the HE or the water can bypass the tube bundle.

Is the exhaust elbow restricted with rust?? The stainless insert in the elbow may have failed. Are you sure the sea water pump is 100%?

DougR

[Katmand]

I'm 100% salt water. It's a new boat for me probably a long time since flushed. The grate does look pretty clean so maybe this is the wrong place to spend time... I don't seen any corrosion in any elbows, etc...

I'll try the thermostat next.... I pulled off the outflow clamp from the heat exchanger while it was running for just a few seconds and water flow looks pretty good..

[Katmand]

Back to square 1. I redirected the intake to a barnacle buster solution and soaked the entire raw water intake system overnight. Engine has great water flow (noted from the redirected intake into a large bucket), replaced thermostats, no corrosion obvious on either side of the heat exchanger. Not sure what's next....