Ford Lehman 120 oil coolers

With the new ones do as Marin mentioned. Sand the area on the coolers were the mounting strap touches the coolers to bare metal, as well as cleaning off the insides of the cooler mounts. So they all make good electrical contact.

What exactly did your "corrosion analysis" entail?

The oil cooler from the port engine and the tranny cooler from the starboard engine looked better than the first one. I still have to crawl over the starboard engine and replace the oil cooler. Not looking forward to that bit of gymnastics. After that it's a haulout to replace the cutlass bearings, fix some through hull valves and connect some more plumbing. Then finally, a year later, we'll get to take her out and play with her!

Marin,

Thank you for the history of FL 120. We currently have the FL SP 135 and have never had a serious issue with the base engine. I have been told that the FL 120 has a potential cooling issue with number six hole and injector pump also a potential problem. It is my understanding the the SP 135 has corrected those potential problems.
Ken

Capt.Bill11 said:

...What exactly did your "corrosion analysis" entail?

Click to expand...

We had a corrosion survey done by electrical tech who used a silver/silver-chloride electrode. We wanted to see if our bonding system was in good order and that we didn't have any stray current in AC or DC systems. We checked every breaker (AC/DC), bonding point plus all the neutrals, grounds and shore power.

The results showed that the bonding system and AC/DC systems were fine and we were within the recommended range of -550 to -1100 millivolt. We tested -635 millivolts. Since at the time we were in brackish water, the tech suggested we get a little more negative so we switch to aluminum anodes. After the change we retested and the reading was -1028. The tech charged for the 1 hour it took him with me flipping switches and breakers.

Old deckhand said:

Marin,

Thank you for the history of FL 120. We currently have the FL SP 135 and have never had a serious issue with the base engine. I have been told that the FL 120 has a potential cooling issue with number six hole and injector pump also a potential problem. It is my understanding the the SP 135 has corrected those potential problems.
Ken

Click to expand...

I have had zero experience with the FL135 and don't know anyone personally who has a boat with that engine. So other than knowing the name of the base engine and that its injector pump uses oil circulated through from the engine as opposed to a self-contained sump, I am basically clueless about it.

The FL120 can have a cooling issue with the number six cylinder which is one of the several reasons to operate it relatively conservatively (1500-1800 rpm) to help ensure that the last cylinder doesn't overheat.

Old deckhand said:

Marin,

Thank you for the history of FL 120. We currently have the FL SP 135 and have never had a serious issue with the base engine. I have been told that the FL 120 has a potential cooling issue with number six hole and injector pump also a potential problem. It is my understanding the the SP 135 has corrected those potential problems.
Ken

Click to expand...

There are a number of "updates" on the 135's vs the 120's. Injector pump oil circulated from the engine oil, improved head bolt and head gasket design, improved water pump shaft design, stainless steel exhaust water injection elbow, automatic closed cooling air bleed setup to name some. I have 2 with about 4800 hrs on them and they run extremely well.

Ken

kchace said:

There are a number of "updates" on the 135's vs the 120's. Injector pump oil circulated from the engine oil, improved head bolt and head gasket design, improved water pump shaft design, stainless steel exhaust water injection elbow, automatic closed cooling air bleed setup to name some. I have 2 with about 4800 hrs on them and they run extremely well.

Ken

Click to expand...

Ken,
Thank you,
Ken

I think the FL120 gets blocked around no.6. One of mine is silted up, about to do a flush. AD says there is a block drain in the vicinity
Fortunately oil coolers are not too pricey,must be a non custom generic.

Capt.Bill11 said:

While I agree coolers should be changed before they go bad, I've lost track of how many coolers on Lehman's I've seen go bad and I don't recall ever seeing one trash an engine or tranny.

So it's not automatically the end of the world if one goes bad.

Click to expand...

When I was in Miami, I spoke to an expert in marine transmissions, he reiterated what Capt Bill said above.

He really liked the BW Velvet Drive transmission and said it's almost bullet proof.

I think my BW was close to being trashed due to water getting into the reverse cylinder. After the first year I owned the boat I pulled the tranny to do a "precautionary" rebuild. The rev cyl had rust in it and was just starting to self destruct.
I caught it just in time.
I am assuming water got in via the heat exchanger sometime under the previous owner (I put a new one on before I ever ran the boat).

Hi, so I did a search on FL120 flush and it brought me to this thread. Is there a procedure for how to do this? I'd like to do mine before opening day.

It seems from memory that Daddyo had this problem recently. Transmission cooler failed and caused the trany to have to be rebuilt. They are too cheap to not replace once in a while. I bet you could buy ten of them for the price of rebuilding a transmission.

dhmeissner said:

Hi, so I did a search on FL120 flush and it brought me to this thread. Is there a procedure for how to do this? I'd like to do mine before opening day.

Click to expand...

Get a 5 gallon bucket, a bilge pump or submersible A/C pump, some TRAC Barnacle Buster (or other mild acid) and get 2 hoses. One that fits on the outlet of the pump in the bucket and then connects up to the first fitting just down stream of your raw water pump. The second hose connects to the last vooler inline. Which in the case of a Lehman should be the transmission cooler. From there the hose returns to the bucket.

Close the seacock to your raw water pump and hook the hoses up. Fill the bucket with the flushing fluid and let it circulate for at least a couple of hours or more if you're using Barnacle Buster.

After that stop the pump and drain the fluid back into the bucket then reconnect your raw water hoses and fire the engine up to check for leaks at the hoses you disconnected.

if you go to a local supermarket and buy some 8 or 10% strength vinegar, pass it slowly through your cooler until it clean, cheap and effective, job done.
Great for cleaning toilet pipes too !

waddenkruiser said:

As long as they run - don't tinker.

(I'm nocking on wood, never changed them on my boats, up to 40 years of service)


best regards / med venlig hilsen
wadden

Click to expand...

Knocking on wood isn't good enough, sometimes:
During my seasonal maintenance work I checked our coolers for possible leaks. Fotos taken with the camera looking bottom up identified some corrosion issues on starboard oil cooler and an incipient corrosion at the heat exchanger on the same engine. Don't know how long the oil cooler looks like that, it is the starboard engine so normally no chance to get a glance at the bottom of the cooler ...
As long as they run - don't tinker. For the time being engine is still running.
Do you have any idea about rest of lifetime?
While the oil cooler looks for me to be at a later stadium the heat exchanger seems to be just at the beginning of corrosion development
And: any ideas for repair or should I just go for replacement?

Or am I wrong and it isn't a corrosion issue?

I would appreciate your ideas!





best regards / med venlig hilsen
wadden

Wadden
Looks exactly like a zinc fitting on top in your top picture, but I don't see any wrench marks on it!
I pulled my T coolers and found lots of rubber bits, but as the zincs had been properly maintained, no electrolysis. A little acid cleaned the scale out, so good as new. This after 20 yrs and 5000 engine hours. Clean your up and you may find they have lots of life left in them.
Do the zincs.

koliver
I checked the FL operators manual for zincs. It seems that there isn't a zinc, neither at the oil cooler nor at the transmission oil cooler. Only the main heat exchanger has got a zinc which I check once a year.
I identified the screw on the picture as a drain plug (ref. 3 in the drawing). Might be I'm wrong, will check next weekend. Do you know zincs for 1/8 NPT?




best regards / med venlig hilsen
wadden

Greetings,
Mr. wk. The first picture does show corrosion BUT you should remove the cooler and have a radiator shop (I have no idea what the equivalent is in Europe) perform a pressure test to determine IF it is from a leak in the jacket or simply external corrosion due to a poor paint job and exposure to a salt atmosphere. Manufacturers do NOT use a premium paint to coat their coolers. Probably the cheapest spray can paint available.

Oil and transmission coolers are considered maintenance items which should be changed on a regular (every X years?) basis. They are not terribly expensive and changing to cupro-nickel coolers should give you many years of worry free use. Keep the originals as spares after cleaning in the manner suggested by Mr. k.

I have seen oil and transmission coolers with and without zincs and I agree with you, pic#1 depicts a drain rather than a zinc holder.

My opinion only.

The tiny fitting is a drain plug.


As for length of service...roll the dice. There are cupronickel ones and more common brass ones....I have heard the brass are on about a 5 year changeout schedule for heavy use...the cupronickel are for either life or till you can't stand it any more.


I had a brass one have the end cap fall off last year on a 454 gasser motor...the solder joint failed. Looked like a manufacturers defect rather than corrosion. But that failure was right at the towing companies 5 year changeout schedule so who knows.

Thank you Gentlemen


best regards / med venlig hilsen
Wadden