draining heat exchangers

[jim rosenthal]

This would be easy if you didn't mind making a mess. However, everyone on this forum DOES mind making a mess, especially in their engine room, so here's a short account of what we did today: (we being me and a tech from T&S Marine, the Cat/Cumminds dealer in Crisfield, MD)

Although my HEs have been flushed on the engines, it was time for them to come off and be really cleaned at a radiator shop. Since T&S were going to be in the area, they offered to have someone stop by and show me how to do all this. Very useful offer, I should add.

On Cummins B diesels, there is a long pipe on the lower stbd side of each engine, with a small drain plug (Allen head) at the bottom. We used a rig they brought which has a little Rule bilge pump in a small plastic bucket. That goes under the plug, plug comes out, the coolant begins draining (take top tank cap off), taking about ten minutes to empty completely. Pump has enough lift and push to pump the coolant into a leftover hydraulic oil bucket with a spigot on top, which can be capped. Each engine holds about six gallons. So, three buckets. You all with DDs will need a lot more buckets, I think.

Loosen and pop off all the hoses. There are four- two in, two out. Once the coolant is drained, you are unlikely to encounter any more liquid, but we did find a little winterizing AF on one side. But not much.

Having a blunt pick helps to get the hoses off- on mine, they were pretty much sealed to the spigots of the HEs by age and heat and the clamps.

CAREFULLY undo the four bolts which hold the HE to the engine. If you do this right, the paint seal will hold the curved HE mounts in place long enough for you to remove the HE and put the bolts back in, thus preserving the mount position and making replacing the HEs much easier. At this point, ykou make a list of the stuff you're going to replace- hoses, clamps as needed, zincs, and call the Cummins dealer. You will also need end cap seals.

Drive to radiator shop and drop off HEs. Mark them for P & S. Yes they are supposed to be identical, but why make trouble for yourself?

Drive to Cummins and buy 12 gal of blue Fleetguard AF.



Tomorrow, the HEs are supposed to be done- if not then, Friday. I'll pick them up, paint them and let them dry for a couple of days, and then put them back on. My engines do not run warm, but after ten years and only flushing them on the engines, which only cleans the seawater side, it was time.

Updates to follow. This is not a difficult task, at least on these engines, but I was impressed by how quickly we got them drained and off the engines, and spilt almost nothing at all.

 

[Photolomy]

Is Fleetguard AF good for DDs also?

 

[Jammin']

How did they look when you got them out? My 6-71's are being done this week or next, hopefully. I wanted them removed for the same reasons plus I want the bolts that are going to break to be broken off now when they can be dealt with.

 

[jim rosenthal]

They did not look too bad, actually. But they needed to be cleaned. Yes, the aftercoolers are due next winter. The design of the Cummins aftercoolers is such that they should not go long between maintenance services- the copper-nickel core is entirely too close to the aluminum alloy housing. Other companies build them the same way, but the clearance between the housing and the tube bundle is bigger and better on Cats at least, according to Tony Athens.

Today we got the port HE back in. I only had one kit of HE end cap seals, so we only got one HE back in- parts are coming for the other one tomorrow, plus some replacement constant-torque clamps. And zincs, which it turns out I have got a couple dozen of already, oh well.

Today's lesson- it is IMPOSSIBLE, on a Cummins 370B engine, to get the end caps off the HEs without taking it off the engine. Even if you could get the end cap bolts loose, which would be just possible, there is so little clearance that you can't get the bolts out, and get the caps off. However, you CAN install the end caps, seal, and rubber washer, snug everything up, and finally tighten it with an open-end wrench, with the HE mounted to the engine....

What is somewhat intimidating here is that splash and startup of the engines is a month away... so if I've screwed this up, you all will hear the howl of dismay all the way in FL and NC just by opening the window, it will be that loud. But if I've messed this job up, I'll post an account of it and what I did wrong, in the hopes that it will save some other HOF member from making a similar mistake. Stay tuned.

 

[jim rosenthal]

As to bolts breaking, I totally understand. I am very careful about spraying the engine room with WD40 when I put the boat up for the winter. So far, so good, on frozen rusty bolts.

There is a considerable difference between cleaning the HEs ON the engine, which basically means flushing the seawater side, and taking them off and having a radiator shop clean them up. Really, there is hardly a comparison. They came back looking new, inside and outside. One of the reasons I did this is that the engine coolant was several years old and needed t be changed out. Regardless of how much trouble it may or may not be, maintenance is far cheaper than changing out engines.

On another topic, does anyone know of approved synthetic oils for use in marine engines? The last time we discussed this, I believe there weren't any.

 

[jim rosenthal]

All back together. Startup is weeks away, but they didn't leak when I refilled each system with AF. According to the Cummins dealer, T&S, the advantage of the blue coolant is that it is less reactive with the aluminum parts of the engine that it comes into contact with. Now, what those are, I couldn't tell you. The heat exchanger is either bronze or CuNi, and the AF doesn't contact either the aftercooler or the gear oil cooler. Maybe these engines have aluminum heads?

Still to come- replacing all the other zincs, which means the aftercoolers and the gear coolers, and going over all the hose clamps, hoses, engine mounts, etc. And at some point I have to drain and refill the genset coolant and oil.

 

[Photolomy]

Where do you dispose of the old AF?

 

[Scarlett]

I took mine to an oil change place, they took it no problem as coolant changes are one of the services they offer. John

 

[Finalee]

Jim the part of the bay your in is fresh isn't it? I do my B's every other year regardless of hours which are 200 a year. Very little build up here at the Salt Ponds. I can see the Atlantic from the harbor. The cylinder heads are cast. NTB takes af here in Hampton.

 

[jim rosenthal]

No, it's brackish here, and we get huge amounts of filthy runoff from the Conowingo Dam every spring. Our county, Anne Arundel, has containers for both waste oil and AF at the local landfill/recycling center. No limit if you live here, as far as I can tell. I took about twelve gallons over there.

What I wish I had was a way to burn the waste oil from all my oil changes, but I'm not set up to do it. I don't think I could just put it in my house;s oil tank, I suspect it's too dense and too dirty for that. But with all these cars, it adds up to a lot over a year.

 

[whoover]

Hello Jim,

Don't pour the old oil into your heating oil. I tried this with my workshop furnace by diluting one gallon of oil to four gallons of furnace oil. I was cleaning my oil burner once a week, it would not burn properly and stop igniting. It would always happen when the outside temperature was 20F of lower.

I save my old coolant to winterize my engines in the fall and a little bit goes into the pressure washer because my storage shed freezes.

Walt Hoover

 

[jim rosenthal]

I know. There is such a thing as a waste oil burner which is built for using waste engine oil and ATF, but my garage isn't big enough for it. And the garage where I keep my cars isn't mine, so it's not practical to put one there. It would be nice, though. No one makes a small waste oil burner that I've been able to find. Wish they did, I'd buy one.

 

[dsharp]

What is the preferred material for heat exchanger fasteners? Stainless or regular cad plated bolts?

 

[jim rosenthal]

Not sure what you mean. Mine, on Cummins B series engines, are held onto the engine by steel bolts, from Cummins, screwed through rubber and steel mounting pads. Can you clarify what you are asking about?

 

[Jammin']

The Detroit mechanic working on my 6-71's replaces the bolts with stainless when he removes them. He says he uses anti-seize on them, although I've heard of people using a marine grease with no metallic content out of concern for electrolysis. I don't know if that's a legitimate concern. I currently have stainless in the port exchanger and grade 8 in the starboard. We'll see what breaks.

 

[dsharp]

I was thinking more about the Detroit style. I think they’re 5/16 bolts and it seems like at least 1 will break if the previous mechanic failed to use an anti seize product. Some of the stainless today is pretty soft.

 

[Finalee]

Avoid the guess work and use what Detroit sells.

 

[racclarkson@gmail.com]

Avoid the guess work and use what Detroit sells.

Ditto. Beware of SS galling. Note the heat often generated from just hand ratcheting.

I like to treat steel bolt heads with phosphoric acid and leave overnight. They will have a protective coating on them plus be etched and ready to accept paint.