Heat Exchangers Exchanged

Calling it quits. 

The two high-pressure heat exchangers for oil and transmission fluid have been replaced.

The old main engine cooler has been removed and is ready to be replaced with the new one.


New oil cooler and revised water pump fittings

Also, the essence of the cooling hoses (except for the J-hose) have been removed and are ready to be replaced. I’m reluctant to mess with the J-hose because (1) it’s awkward as hell, (2) it’s full of coolant and (3) it’s in really good shape. I suspect it’s been replaced over the years.


New transmission cooler waiting for reassembly

At this point, we’re down to rubber hose and hose clamp work. 

Which I’m putting off until tomorrow. I’m calling it quits for today.

The physicality of wrestling with Mr. Lehman is remarkably tiring. I’m not a real mechanic. I’m not even sure I could play one on TV. I barely put in three solid hours today and I’m whipped. I’m worried about dropping parts or tools into the bilge or doing some other boneheaded move.

There’s an emotional battle, also. Mr. Lehman doesn’t give up easily.

The Oil Cooler Hose Saga

I really, really, really wanted to break the street elbow off the oil cooling hose. But it just wasn’t going to move. I took the hose off the oil filter, brought it up on deck. I rigged a pipe wrench as a kind of poor-man’s vise and applied penetrating oil and considerable leverage to the fitting. 


The kind of leverage that has broken the heads of bolts in the past.

It. Did. Not. Budge.

I even resorted to hammering with no useful result. Hammering. 

So what’s the fallback plan? How do I reassemble the oil cooler when I can’t spin the fitting down properly?

Or can I?

The idea here is that the street elbow screws into the cooler at an optimal angle. Then the hose can be easily screwed into that elbow. The hose has a rotating coupling (like any good high pressure or hydraulic hose or propane.) So it should be easy. Line up the hose and spin it into a fitting that’s already at the optimal angle.

The rotating section of the hose still works, but the street elbow is on the end of the hose forever.

I can screw the hose into the oil cooler by spinning the whole hose assembly around in big awkward circles. Impossible to do when the hose is connected to a filter. Easy to do when the hose isn’t connected to anything.

Once the hose is screwed onto the cooler, I can screw the other end of the hose into the oil filter.


The oil filter is awkwardly placed at the aft end of the engine. You can’t see up underneath it to thread the hose back in. And you can’t simply screw the hose in because you have to twist the entire hose all the back to the rotating coupling at the oil cooler.


Okay. Okay. Okay.

Bob Smith (of American Diesel who designed these engines) says “Some people make trouble for themselves by not taking enough things apart.”

Got it.

I took the oil filter assembly off the block. Wrestled filter and heat exchanger around so that I could spin the hose and thread it into the oil filter. 


Now to reassemble. Wrestle the filter into position. Wrestle the cooler into position. Put in the bolt that holds the filter in place.

Wait. I Can’t put the bolt back into the hole it came out of.

The bolt that holds the oil filter onto the block no longer fits through the bracket!

It came out perfectly fine. It won’t go back in.

Why? Because now there’s a hose in the way.


Wrestle everything back into a position where the hose can be twisted. Twist the hose to unscrew it from the filter. 

Put the bolt into the filter bracket.

Put the hose back in, wrestling with twisting the hose around and around between the filter and the cooler. Can’t tighten the hose anymore? Good.

Wrestle the filter (with bolt) back into position. Find a way to get the wrench back in there to tighten up the filter bracket. I can also rotate it slightly so it doesn’t rub on a fuel hose.

Wrestle the cooler back into “dry fit” position. Until the raw water hoses are assembled, I don’t want to put the bracket in place.

Unkink the hose. Again.

Bolt the filter back onto the block.

Sigh with contentment at a job mostly done. 

Main Engine Cooler

The main engine cooler is still in acceptable condition. Some of the cooling tubes are plugged. But. It’s the kind of thing that we can now clean carefully and keep as a spare.

Some folks suggest carefully pushing a dowel through each tube.

Other folks suggest washing in mild acid. Lime Away, for example. Or vinegar.

Some folks suggest strong acid. Muriatic acid to be specific. I think that’s a brand name for dilute hydrochloric acid. Not sure I want to mess with this.

Some folks suggest high pressure clean water. Just hose it out. No acid.

Tough choice. Not sure what to do.

Tomorrow’s Activities

1. Connect the main engine cooling hoses back together. That’s four large chunks of preformed elbows and straight sections from the expansion tank to the cooler and from the cooler to the exhaust manifold.

2. Connect the raw water hose. This is a bit more work. There’s a small straight section from pump to oil cooler. A right angle from oil cooler to main cooler. A right angle from main cooler to transmission cooler. And then a long straight section to the injection on the exhaust riser.

3. Stare at it for a while to be sure it’s really all there.

We are probably going to a party in Ghent tomorrow night. I’m not sure if I’ll have everything together enough to run a test or not Friday afternoon. I may not get to test anything until Saturday or possibly Sunday.

© Steven Lott 2021