When to replace...??

firstbase · Nov 11, 2017

Ford Lehman 135's. The heat exchangers, oil and tranny coolers were taken off, pressure tested, and "serviced" by the previous owner in 2013 prior to cruising. He paid to have the work done, didn't do it himself. They were given a clean bill of health, repainted in that nice Ford Lehman red and put back on.

OK. Now I own the boat. Have no idea how old the HE/coolers are. opened up the HE when I flushed the system w/Barnacle Buster and they looked fine to me. the exteriors look brand new (PO was a meticulous engine room guy) Of course that was the first HE I ever looked at so take that comment with a grain of sand.

I believe the worst thing to happen ion the group is the tranny cooler going kaput and allowing water into the trannys. Rebuild time. Now call me crazy but I would rather stay away from that.

My question is...when do you replace these? Wait for something to happen or is it a wise decision to say "That's long enough and I will just feel better with new ones"? Any rule of thumb on these?

koliver · Nov 11, 2017

firstbase said:
Ford Lehman 135's. The heat exchangers, oil and tranny coolers were taken off, pressure tested, and "serviced" by the previous owner in 2013 prior to cruising. He paid to have the work done, didn't do it himself. They were given a clean bill of health, repainted in that nice Ford Lehman red and put back on.

OK. Now I own the boat. Have no idea how old the HE/coolers are. opened up the HE when I flushed the system w/Barnacle Buster and they looked fine to me. the exteriors look brand new (PO was a meticulous engine room guy) Of course that was the first HE I ever looked at so take that comment with a grain of sand.

I believe the worst thing to happen ion the group is the tranny cooler going kaput and allowing water into the trannys. Rebuild time. Now call me crazy but I would rather stay away from that.

My question is...when do you replace these? Wait for something to happen or is it a wise decision to say "That's long enough and I will just feel better with new ones"? Any rule of thumb on these?

Your concern seems a bit like asking, "when do I replace my boat?"

I have never heard of anyone replacing HEs as Preventive Maintenance. They are made of brass. They get a buildup of scale, but that can easily be removed, mechanically or chemically. If you use a coat hangar to poke out the tubes, theoretically you can scrape right through the brass tubes into replacement territory. I have seen people worry about this on forums and occasionally have heard this fear verbalized. I have never heard of anyone actually doing it. Use a wooden dowel. Use muriatic acid. Take them to a radiator shop. If really, really concerned, a rad shop can pressurize them to check for leaks, then repair them if they blow apart.

But Hey. I know only what I have seen, heard or read on a Forum.
Ask a real expert, like a Rad shop.

firstbase · Nov 11, 2017

So, in the case of the transmission cooler, you just wait until it is toast and allows water in the tranny and then replace the cooler when you rebuild the transmissions to get the water out? Doesn't seem like the thing to do but hey what do I know. Cost of ownership I guess.

kapnd · Nov 11, 2017

You can clean them, pressure test them, and sail away with some degree of confidence.
Regular fresh water flushing helps insure long life from these items.
You’re more likely to encounter cooling system problems from the rubber items involved, I see many OLD motors sporting ancient, possibly original hoses and clamps, and hard cracked belts, impellers with one or two vanes remaining.

Peter B · Nov 11, 2017

firstbase said:
So, in the case of the transmission cooler, you just wait until it is toast and allows water in the tranny and then replace the cooler when you rebuild the transmissions to get the water out? Doesn't seem like the thing to do but hey what do I know. Cost of ownership I guess.

First base, I have a Lehman 120, and the transmission heat exchanger has only been replaced once in the last 20 years, along with the main engine HE) - possibly longer, but I had it done about 4 years ago, I've had the boat 16 years, and I know the PO had it 5 years and didn't touch the engine other than routine oil and filter.

The manufacturer's manual for the engine suggests changing them at about 5 year intervals, but like most things with a stated best by date, they last way longer. Changing the zincs is the thing. They corrode over time, but not that quickly. The take home massage in boating is it's expensive enough. There is always something, so..."if it ain't broke, don't fix it!"

SoWhat · Nov 11, 2017

Tough question. They don't give any advance warning when they finally go. Your tranny will be full of water. If one goes, you can assume the others are in similar condition and will all need replacement. Did the PO change the HE zincs each year? Did the PO drain and flush all raw water from the system each winter?
The price of replacing everything including hoses is probably $1500-$2000.
The price of rebuilding 2 transmissions is probably $1500-$2000.
Considering the value of your boat and peace of mind I would say replacement is appropriate.

Oil cooler seems to be the problem child so make sure it is solidly grounded to the engine black. Ongoing I would expect 5 years of service life, more if your OCD.

BruceK · Nov 12, 2017

I seem to remember researching this, 2000 hours for the transmission and oil coolers is in my mind. They are quite inexpensive, esp compared to the main HX, though my replacements, as advised by the mechanic, came in grey undercoat, I had to paint them red myself. Kind of suggests a semi stock item. Seakamp made mine, I think.
If you are concerned, and at at some point you are right to be, just renew them.

psneeld · Nov 12, 2017

There are 2 kinds listed in my parts manual and what I have seen on aftermarket sites.

Copper and cupro nickel.

I believe the 5 year cycling is for the less expensive copper....havent heard a number for the cupro nickel ones. I would guess 10 years might be a good number but sooner couldnt hurt but money and 15 is likely to be a better number as cupro nickel if built well should last a very long time if erosion from silty water isnt an big issue.

firstbase · Nov 12, 2017

Thanks folks. The "manufacturers suggested" replacement period is what I was looking for as a benchmark. I have the records showing the dates "service" but can't find any reference to hours on engines when done. Do know that the PO did the loop and then brought the boat down to Florida from Wisconsin. I am estimating that at about 1000-1200 hours since the service or so but that is only a wild guess and again have no idea how old they were at that point. I have no signs of anything bad going on and will probably factor replacements in over the next year. Maybe some think it a foolish waste of money but I don't think it is an unreasonable cost as they aren't really expensive and I can change them out myself (after two dozen newbie question threads on TF of course).

firstbase · Nov 12, 2017

psneeld said:
There are 2 kinds listed in my parts manual and what I have seen on aftermarket sites.

Copper and cupro nickel.

I believe the 5 year cycling is for the less expensive copper....havent heard a number for the cupro nickel ones. I would guess 10 years might be a good number but sooner couldnt hurt but money and 15 is likely to be a better number as cupro nickel if built well should last a very long time if erosion from silty water isnt an big issue.

Thanks. Is there some way of telling which they are? Is there something in appearance that would identify one or the other? I haven't searched for a part number stamp on them or anything. Will try to look today.

Bay Pelican · Nov 12, 2017

Call Brian at American Diesel. He will give you the recommended replacement life of each HE varying by metal on a Lehman 135.

Waiting until they fail is a disaster in waiting. I was religious about changing the heat exchangers on my Lehman but took a short cut on my Westerbeke generator. Had its heat exchanger repaired, which didn't hold, through an odd combination of failures the salt in the coolant cost me $4,000 US.

twistedtree · Nov 12, 2017

After 10-15 years of service, I'd probably be thinking about replacing them too.

But one thing to keep in mind is that if a leak develops, you are much more likely to dump gear oil out with the raw water, than to dump raw water in your gear box. This is because the gear oil is probably running at a much higher pressure than the raw water loop. Specifics will depend on what model gear you have, but the handful I have seen have the cooler on the high pressure side of the oil circuit, so running at 200-300 psi.

jleonard · Nov 12, 2017

I have never heard of anyone replacing HEs as Preventive Maintenance.

Well now you have! I have replaced my tranny and oil heat exchangers 2 times since I have owned my boat. I give them 7 or 8 years in salt water.

sunchaser · Nov 12, 2017

Marine age is what counts for sea water cooled transmission coolers, not hours. My cupro nickel units I replaced at 12 years, they could have gone longer but why risk it. Lots of expert advice out there seems to hang between 10 to 15 years for CuNi and much less for Cu. The failure points are normally in the weldments or brazing materials.

Coolant cooled transmission HXErs are much less common on smaller engines and can last much longer. But they run at higher temperatures which results in different issues.

I paid about $400 each for the OEM CuNi units. I have two brand new Cu ones that I paid around $250 for, I should probably sell them. The transmission HXers, as mentioned, are units you do not want to fail. Surprisingly, the mere act of removing and pressure testing by a amateur can be injurious to their health.

Also, do you check your TX oil each day of cruising for level, color and water?

Larry M · Nov 12, 2017

I went to a Ford Lehman class in Seattle given by Norn Dibble before he retired. He was the West Coast Ford Lehman Guru at the time. My class notes say to replace the heat exchanger at 15-20 years if cupronickel. The oil and transmission coolers every 1700-2000 hours.

You can buy direct cupronickel replacements made by SeaKamp. I replaced everything when we rebuilt the engine. Here are the SeaKamp part numbers and ~ internet prices. These are for the FL SP135

Heat exchanger #: 2C239CN $555
Oil cooler#: 212143CN $128
Trans cooler: 29133CN $111

psneeld · Nov 12, 2017

And definitely different for the 120...I just replaced my oil and tranny coolers.....the ones I got from American Diesel were different than the modified ones the old owner used from his blown up 135 on the replacement 120 block.

Baker · Nov 12, 2017

I think visual inspection will likely tell you the condition of each HX. They get pretty nasty before they fail. And for the folks with higher performance engines, we have fuel coolers and aftercoolers to worry about. I have had a fuel cooler fail....returning sea water to my fuel tanks....not a good thing. Very lucky I got away with just two fouled injectors. Still ended up costing me about $3000.

Nomad Willy · Nov 12, 2017

I replaced mine less than two years ago.
It’s just not that expensive.
My BW works great.

firstbase · Nov 12, 2017

In searching for the oil cooler I see CU, CuNi, and CuNi with zinc anode. I am assuming that if copper/nickel is better then adding a zinc is best. The ones I have now do not have zinc anodes...HE does but not the oil and tranny coolers.

When to replace...??

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