Oil Cooler, Heat Exchanger & Raw water pump overhaul

[mlaloli]

Hi everyone,

I am relatively new to the group, having purchased a clipper 34 back in April that was in major disrepair and spending since then fixing her up.

Her engines (Ford Lehman 89hp 4 cylinder diesels) had not been run properly or under load for about 3 years.

I cleaned out the fuel and tanks and ran her to find the engines overheating..

Pulled the ends of the heat exchangers to find them full and blocked and then traced down to the water pump to find the same. While I was at it I pulled the oil cooler off which was in good condition (obviously the anode pencils were gone).

Having now bathed these items in a barnacle buster, my question is, when re installed do they need to be primed?

IE do I need to fill the exchanger, pump and hoses with raw water?

Also with the oil cooler - do I just fill the oil into the plug where the oil lines attach?

Thanks for your help - as a novice Ive found the forums fantastic with lots of good info..

 

[Russell Clifton]

Within seconds your raw water pump will fill the cooling system with water and the engine will pump oil into the oil cooler. Check the oil level after running as you probably lost a little oil when the oil cooler was removed, same with the fresh water level.

 

[SoWhat]

Agree, no need to prime, but I would replace oil and transmission coolers. If zincs were gone the coolers are next. They are about $100 each. Heat exchangers are $400 each so I would take them to radiator shop for pressure test.

 

[mlaloli]

Thanks everyone,

I put the heat exchanger, pump and oil cooler back on and fired up the engine.

It was pumping water and was leaking around hoses and the heat exchanger and so begun tightening these parts up.... then I snapped the bolt on the end of the heat exchanger so needed to pull it out and drill it out... bugger!

When I took the exchanger to the shop for the drilling I asked about the pressure test and was told not to bother. But then received local advice at the dock I should have as a pressure test is a good way to ensure sea water doesn't enter the coolent or coolent to sea water etc.

Anyway, refitted the heat exchanger today and started the engine. Noticed the water pump stopped working after about 15 min of running.... frustrating! So assume the impellor is directional when fitted (it has a tight section where the blades fold over and assume they need to be bending in the right direction..)

 

[RT Firefly]

Greetings,
Mr. ml. Welcome aboard. I've always been told the vanes in our Lehman 120 would bend into alignment upon starting even if they were bent in the wrong direction on installation.

 

[mlaloli]

Thanks RT Firefly... You did well to understand what I was saying in may last post which I found difficult to describe!

This has me confused why the pump would stop after it has started up and was blowing plenty of water.

I had replaced the impela and cleaned out the pump and all hoses. We had only just launched the boat and replaced the sea cock so I know plenty of sea water is getting to the pump.

I'll refit it tomorrow and hopefully it works second time around..

PS we have the FL89hp x 2 version and this seems quite rare compared to the FL120 which I'm reading a lot about on this forum.

 

[DavidM]

I would consider replacing all of your heat exchangers. Sounds like they were used for a good while with no zincs so could have corroded. And acid cleaning can remove the scale that was blocking the leak- that is why you have to pressure test afterwards.

Your raw water pump may have a worn cam inside which caused it to stop pumping. Maybe the cam was rough and corroded so it screwed up the impeller after a few minutes. Or if you used any grease on the impeller, it washed out and stopped pumping due to the bad cam.

Pull the impeller and check it out and look at the cam.

David

 

[RT Firefly]

Greetings,
Mr. ml. No thanks necessary. Your description was quite accurate. Mr. dj. brings up an interesting point. As well as a worn cam, IF the WPs on a 4 cylinder Lehman are the same as the 6, the old style (original) WPs had an inherent flaw in their drive mechanisms. Something about drive tangs breaking off. Evidently there is a new style WP that eliminates this shortcoming. Sorry about the vagueness but the memory is gone...

 

[foggysail]

Been there, done that.........at least with my ACs water inlet. There is a good chance that you will find the next time you start your problem engine, you could have water flow!

Twice over the last years I have lost water flow for my ACs. The first time I removed the hose from the seacock and had NO WATER to speak of. Problem was that something outside the boat plugged the inlet......plastic bag! The next time it happened, I just shut the valve off and the next day things were fine.

 

[BruceK]

Greetings,
...IF the WPs on a 4 cylinder Lehman are the same as the 6, the old style (original) WPs had an inherent flaw in their drive mechanisms. Something about drive tangs breaking off. Evidently there is a new style WP that eliminates this shortcoming. Sorry about the vagueness but the memory is gone...

The replacement pump is available from American Diesel Corp, incorporates a Johnson pump, about $500US, heavy, so the freight is too, but a nice pump with strong drive mechanism. Hope you get the old one working, but...

 

[kchace]

Thanks RT Firefly... You did well to understand what I was saying in may last post which I found difficult to describe!

This has me confused why the pump would stop after it has started up and was blowing plenty of water.

I had replaced the impela and cleaned out the pump and all hoses. We had only just launched the boat and replaced the sea cock so I know plenty of sea water is getting to the pump.

I'll refit it tomorrow and hopefully it works second time around..

PS we have the FL89hp x 2 version and this seems quite rare compared to the FL120 which I'm reading a lot about on this forum.

The impeller blades do not have a specific direction - they will turn around instantly when the engine is started. If you replaced the impeller with a new one, it could be defective, if you didn't put a new impeller in, the old one could have stripped all the blades after having sat for so long, or you could have picked up a bag on the intake. The first thing to do is take the pump cover off and see what's there. You may find the answer immediately.

Ken

 

[kapnd]

Leftover bits of impeller blades from previous shreddings can hide in the system and cause loss of raw water flow.
A favorite haunt is in the raw water pump intake hose between the strainer and the pump. When the engine starts, they get sucked tight against the pumps intake, and when engine is stopped, they go back into hiding.
Many people only look upstream for obstructions, but they can/will be downstrem too.

 

[hrlewis47]

As a new member, found this thread very helpful as with my 43' Marine Trader, having 2 275 engines, and am commencing on my own servicing on the above mentioned.
Have found my membership already very helpful. Thank you members

 

[FF]

Remember antifreeze too has a service life , on any new, old boat purchase it and the engine oil & filter and tranny fluids should be changed.