Lehman 135 Heat Exchanger Removal

[DBG8492]

I searched but didn't find anything specifically about this. And I'm in a time crunch and need to get this thing removed and replaced.

I was able to get the transmission oil cleaner off without much hassle, but the bolts for the heat exchanger are on the very bottom and basically under the thing itself. I can get a 9/16 ratchet box-end wrench into either side enough to get the bolts loose - and can probably get them all the way out. But of course, the farther out I pull them, the more the exchanger starts to bend backward.

I still have the hoses on it - but I loosened the clamps and worked them back and forth with a large set of channel locks just to make sure they're loose before I pulled the bolts.

My idea was to use a couple of pieces of wood or something to wedge it up, or a ratchet strap over the floor beam to hold it up. It's reasonably heavy considering the restricted space in the engine room of my Marine Trader, and I'm thinking it's going to be super difficult to get the new one in place AND get the bolts in working by myself.

So if anyone out there has done this and has some advice, that would be awesome...

 

[Larry M]

I replaced ours 3 times. The hoses came off first. It’s a bit messy but I timed it with an oil change. Based on the age of your lift pump, it’s never easier with the oil cooler and heat exchanger off.

 

[DBG8492]

I had to wing it.

For anyone else reading this - it's actually a lot easier than it looks. But I was too busy to take pics, so...

What I did:

Pull the transmission cooler lines off, loosen the hose clamps and remove the hoses from the transmission cooler, loosen the nut on the bracket, and remove.

The bracket is held to the transmission housing with one of the transmission mounting bolts - Remove that and the bracket.

At this point, I loosened all the hose clamps on the heat exchanger and let the coolant run into the bilge with the raw water still in the lines. This wasn't the best idea, and if I had to do it again, I'd use a Shop Vac to pull the coolant out of the tank before loosening the clamps - but I was in a huge hurry.

Once the clamps were loose, I used a large set of channel locks to work every hose and ensure it was not welded to the fitting.

After that, you can remove the two bolts holding the tank mount to the engine block. They're 9/16, and I used a deep-well socket with an extension - it JUST fits under the tank and when they're all the way out, the bolt will stay in the socket - easier to retrieve without worrying about it falling into the bilge.

Once the bolts are out, the tank will drop down a little, but still be held in place by the hoses. Work it back and forth, and it's out when the hoses pop loose. And I didn't have to mess with the exhaust elbow - was worried about that...

I had to pull a bronze elbow fitting on the starboard bottom side of the old one to put on the "new" one - which was really just an old one the previous owner had on board. it wasn't rebuilt, but it wasn't garbage, either. I soaked it overnight in a plastic tub with 3 gallons of Evapo-Rust then rinsed it well with fresh water. Still wasn't "new," but it's a hell of lot cleaner.

Putting it on was more difficult.

I rubbed a tiny bit of beef tallow on the inside of each hose - not much - and starting on the starboard side, I pushed them one by one onto the fittings, leaving the clamps dangling on the hose. Once that was done, I put the starboard bolt in using a shallow 9/16 socket and extension by hand - no ratchet. You have to eyeball it sort of from above until the bolt goes in and starts threading. I gave it a few turns and moved to the port side.

Here I used a few pieces of wood that were laying around to push that side up higher by wedging them between the top of the transmission and the Exchanger tank. Had to lay on my side, but I was able to line up the hole in the mounting bracket with the hole in the block, and get the bolt started using the same shallow 9/16 socket and an extension by hand.

From there, I just tightened them both back up, then made sure the hoses were pushed up as far as possible, and tightened up the clamps.

Now I'm having lunch and will go put the transmission fluid cooler back on.

It's not the best job to do in 95* temps in the bilge of a boat - but I've done worse.

 

[Pete Meisinger]

I have never used tallow, but I have used some dish soap in the hoses, kind of messy. The best and easiest way to get stubborn hoses onto a fitting is to heat them with a heat gun. Helps for taking off stubborn hoses also.

pete

 

[DBG8492]

I have never used tallow, but I have used some dish soap in the hoses, kind of messy. The best and easiest way to get stubborn hoses onto a fitting is to heat them with a heat gun. Helps for taking off stubborn hoses also.

pete

I like tallow - lots of uses. And it won't degrade rubber.

I have used a heat gun as well but unfortunately, I didn't have one with me.

In the end, a test run showed the pump not pulling raw water. Not sure why, we just replaced the impeller - but we had other issues that took precedence, so we will leave here tomorrow without having a good test run of the main. Not my ideal situation, but I will have to have a mechanic go down there in my stead as I won't be back until a couple of days before we have to move her and won't have time then to troubleshoot.

Sucks - I hate parting with that money - especially if I'm not there to watch them.

Know any reputable marine diesel mechanics in the North Fort Lauderdale/Pompano Beach area?