Heat Exchanger Question

Question-
I swapped out my port HE this weekend with my spare. What is the best way to clean the one I removed? Muratic acid? How would I go about this?
Also- I have an area on the removed HE that has a lot of wear on the outide where it sits in the cradle on the 135. I am planning on having rubber strips cut at my hose supplier and feel that my best approach would be to wrap a rubber strip completely around the HE (also oil coolers) when mounting. Any thoughts?

Steve

Hi Steve,

I use Phosphoric Acid to clean my Heat exchangers. I clean them on the engine using a 500 gph bilge pump and a bucket to keep cycling it through the exchanger. Use a 5 gallon bucket and a 3 or 4 to one ratio (water to acid) depending on how bad the exchanger is. Mix up water and acid in the bucket and put your heat exchanger in Besure the entire exchanger is covered. The acid is available at Home Depot in the paint department.

Be sure to follow safety precautions, gloves, goggles and pour the acid into the water, not visa versa.

When it quits bubbling its done. Rinse it completely. I also clean my 3 A/C units, both Generators and both main engines with this solution. I keep the mixed solution in a 3 gallon plastic gas can and reuse it. When Its too dirty just mix with more water and use it on your grass.

I don't think I would completely wrap the exchanger. It seems to me like it would tend to keep too much heat in as well as keep any corrosion on the outside hidden.

There is a company in Virginia Beach that uses a commercial hydrocloric acid mix called Rydlyme. The do it in place with a 55 gallon drum on the dock. Although it is not supposed to harm rubber, they removed the impeller before starting. They fed it in the top most hose on the raw water system and took it out at the raw water pump. Google Rydlyme for details of its chemistry.

I used muratic acid, its easy to find and they look new after you are finished. Be sure to dilute it with water, I made the mistake of using just acid and it makes on BIG mess.

I took my heat exchanger to a reputable radiator shop and they took it apart and cleaned it like new for $80.00*
Do you have Perkins 135 HP?* My heat exchanger is aluminum with brass tubes seperated with a*rubber gasket.* I was concerned about the different metals and how they would react to acid.*

Max,
We are running Lehman's. The exterior looks to be copper with brass end plates bolted on. I had new gaskets along, with some spares, cut at my hose supplier. I had my spare HE cleaned at my radiator shop, looked great- but he would not charge me since it was for the boat. I kind of hate to bring him the removed part- was hoping to handle it myself and have it onboard as a spare.
Steve

Taking it to a radiator shop is the best way to get it cleaned. They will also pressure test it and plug up any leaky tubes. If you want to DIY, you can use Rydlyme or muriatic (hydrochloric) acid. If you use the acid, dilute it 50% with water. Remeber to ALWAYS add acid to water (a comes before w). If you pour water into the acid, it will boil and splatter you. Not a good thing. Mix it up in plastic, and immerse the HE in it. If you have to do it one end at a time, make sure each end gets about the same time. Rinse with lots of fresh water when you're finished.

Two more questions-
Any maintenance on oil coolers (one for trans, one for engine oil), and how many quarts should my Lehman 135's hold. I am changing the oil this week.
Steve

According to American Diesel, if you're using copper/nickle heat exchangers, the oil cooler should be changed at 2700 hrs., and the tranny cooler at 2000 hrs. Clean as necessary in between. If you have no idea when they've been changed, I'd do it now, then you have a baseline. I'd also replace the high pressure rubber oil lines. If one of those goes, you can lose the engine.

The Lehman 135 holds 14 quarts of oil. Drain and refill with exactly 14 quarts, and re-calibrate your dipstick to reflect this. With the engine installed and tilted, you'll likely overfill it if you don't re-calibrate the dipstick, which was designed to measure the oil level with the engine flat on a truck or tractor.

Keith, I'm thnking that Bob Smith told me 14 1/2 quarts instead of 14. That' what I've been using for the past 1500 hours and seem to work fine.

The way I recalibrated my dipsticks was this. The tube that the dipstick slides into is just pressed into the block. Once I changed the oil and put the 14 1/2 qts in, I measured how much the stick needed to be lowered, and removed the tube and cut it down the proper amount. Now the original marks on the dipstick are correct.

By the way, both of my transmission coolers failed at about 700 hours, but at 12 years of age. Like Keith said, if you don't know if / when they were changed, I'd change them for sure.

Steve,
About the wear on your heat exchanger. I just repowered my Willard and I had the H E mounted on a bulkhead where there is no vibration. To justify what I did I wonder if the wear you saw could have been prevented by remote mounting the H E.
Eric Henning
M/V Willy
Thorne Bay AK

I can't speak for the FL135 as it's based on a different Ford of England diesel (the Dover) engine than the FL120 which is based on the Ford Dorsett engine. But Bob Smith at American Diesel told me that the reason it's very important not to overfill the sump of the FL120 is that the engine's rear oil seal is not meant to be imersed in oil. With the engine tilted aft, filling the sump to the factory full mark will put in something like 14 quarts or so, and this plus the rearward slant of the engine will immerse the rear seal in oil. That's why it's so important to fill the FL120 with 12 quarts and re-mark the dipstick (or shorten the dipstick tube, whatever works for you).

I don't know if the don't-imerse-the-rear-oil-seal thing applies to the FL135.

-- Edited by Marin at 00:29, 2007-11-06

IN MY BOAT, when I change the oil in my Lehman 120, I add the 12 quarts required then it rises to the MINIMUM mark on the dipstick.
R,

It will all depend on the engine angle. Twelve quarts in our Lehman 120s comes to just below the factory minimum mark on the dipsticks.

American Diesel gave me a good suggestion awhile back, and that was to drain or pump out the lube oil in our FL120s at oil change time, add ten quarts and mark this level on the dipstick. Then add the last two quarts. Assuming one has already marked the 12-quart level on the dipstick you now have a max and min mark on the dipstick which will make it easier to judge oil consumption.

WHAT does oil in a Lehman have to do with heat exchangers?

There was a two-question post a few posts back about lube oil heat exchanger maintenance and how much oil should be in a Lehman.

The folks around here that I know with Lehmans don't maintain their lube oil/transmisison fluid heat exchangers, they just change them every x-number of years or x-hundreds of hours. There's not much to maintain unless a pump impeller comes apart and sends rubber bits downstream to jam in the tubes. Basically, the exchangers either don't leak or they do, so the object is to change them before they start to leak.

Make sure when ordering new exchangers from American Diesel or anyone else that you specifiy cupro-nickel exchangers. These last a whole lot longer then the other type. The little oil and transmission coolers are not very expensive--- I bought a spare set a year or so ago and the cupro-nickel ones were about $70 each as I recall.

It's a good idea to tie them into the boat's bonding system. Some of them are supplied with little replaceable zincs (the ones from AD aren't), and some of them have a tab for attaching a bonding wire (the ones from AD don't). What AD advised me to do is clean the paint off the exhanger where the metal clamp fits around it, and make sure the underside of the clamp was bare metal. So when the exchanger is mounted, the clamp and its mounting bolt will tie the exchanger electrically to the engine block.

dougd1 wrote:

WHAT does oil in a Lehman have to do with heat exchangers?

Click to expand...

One of them cools that oil directly.

"There's not much to maintain unless a pump impeller comes apart and sends rubber bits downstream to jam in the tubes."

To prevent this hassle I always install a Y filter in the rubber pump output.

Sendure the folks that make heat exchangers sell Y strainers in a variety of sizes.

When a rubber impeller finally dies and chunks come off they are captured in the Y strainer , which is but a moment to clean. Replacing the dead impeller will take far longer.

I have NO idea why mfg. continue to use these rubber pumps , when most are low enough(centrifugal needs to self prime) to be similar to a car water pump style that lasts decades with no service.

No requirement to install a new impeller every few hundred hours (more often in murky water) and remove the impeller for winter storage,guess that last buck is more important.

FF

FF-

I don't know this for sure, but I believe that a flexible impeller pump will move more fluid than a rigid impeller pump of the same size. The rigid impeller pumps I'm familiar with, all of which are on automotive or marine engines, have impellers that are fairly large.

By contrast, the flexible impeller pumps in the raw water pumps on our diesels, or in the lower units of the various outboard engines that we have, are much smaller in diameter yet they pump a hell of a lot of water for this size. I believe this is because they can make a very tight seal to the chamber walls, where a rigid imipeller pump has to have at least some clearance. So the flexible impeller pump can be quite small yet still move a large volume of fluid.

And I believe that because of the clearance needed by the imipeller in a rigid-impeller pump, they either cannot self-prime at all, or at best do a very poor job of doing it. The tight seal of a flexible impeller allows the pump to self-prime even if it has to pull or lift the fluid a long distance. It's true that on some applications the pump may not have to self-prime, but in most of the applications on our boat, for example--- generator, main engines, macerator pumps, etc.--- they do.