T-fitting in Raw Water Circuit

[AlanO]

We have overheating issues with our Universal 5432 and substantial amounts of steam mixed with the exhaust. I had a mechanic check the freshwater/coolant side of the heating system at the beginning of the summer and everything appears to be fine. When he sea-trialed the engine for an hour, it did not overheat. I have also checked the impeller and inspected the raw water strainer, both of which were fine. Over the summer I found that the amount of steam being generated seems higher than last summer. Temperature-wise it is fine for several hours, but eventually creeps up to around 200F, which I mitigated by throttling back and removing the engine cover. That got us through the summer. When I started the engine for a day trip last weekend, I noticed small amounts of soot initially mixed in with the exhaust stream. I viewed several of the threads in the forum on this maintenance issue (there are many!) and consulted Casey's maintenance book. Constriction in the exhaust elbow or related hoses seems to be a common problem and worth checking next. There is water coming out the exhaust, but with my limited experience I am not sure the volume is adequate. So now I am tackling the back-end, starting with the hoses from the heat exchanger to the raw water injector to the exhaust elbow, the exhaust elbow itself, and other associated hoses and connectors downstream.

I noticed a t-pipe connector between the heat exchanger and the raw water injection point at the exhaust elbow and I am unclear of its purpose. Both the 5432 service manual and E38-200 users manual appears mostly mum about the exhaust system and were no help about that fitting. A hose is connected at the T that appears to run to the exhaust thru-hull, and perhaps acts as a secondary outflow point for the raw water. I have also seen mention of an anti-siphon valve between the heat exchanger and exhaust elbow injection point, but the pictures don't seem to look like our setup. Before tearing things apart, I thought checking with folks on the forum might be able to identify what this is for.

Thanks.

Alan

 

[Kenneth K]

I noticed a t-pipe connector between the heat exchanger and the raw water injection point at the exhaust elbow and I am unclear of its purpose.

A hose is connected at the T that appears to run to the exhaust thru-hull, and perhaps acts as a secondary outflow point for the raw water.

A T-fitting that vents to the exhaust thru-hull most likely is your anti-siphon loop. It vents water when the raw water pump is operating, and vents air after it stops.

As to exhaust blockages that cause steaming, first check the elbow where water from the HE is injected into the exhaust riser. This area, where warm water hits very hot exhaust gasses is a common source of scale build-up.

 

[Christian Williams]

When was the heat exchanger last boiled out? Heat exchanger is the most common cause of gradual increases in engine temperature. They need a thorough acid cleaning every five years, or even more frequent. See the comments in this thread (Comment #7 and subsequent):

Marine Diesel Cooling System Upgrade 2020

Symptoms: Apparent decrease in water volume at exhaust. Temperature RPM limitation at Wide Open Throttle. Steam from exhaust at idle. Solution: clean heat exchanger, optional general upgrade. When I took over Thelonious II four years ago, the boat would run at near seven knots all day at...

ericsonyachts.org

It's hard to say what a "normal" exhaust looks like from a waterlift muffler, but here's a video. We probably can't judge the hx by volume of water expelled. since buildup of salts inside doesn't mean only less water, but that the efficiency of the heat exchanger is reduced.

I think some steam is normal and I usually have some. How much may relate to the dew point.

 

[Slick470]

A T-fitting that vents to the exhaust thru-hull most likely is your anti-siphon loop. It vents water when the raw water pump is operating, and vents air after it stops.

As to exhaust blockages that cause steaming, first check the elbow where water from the HE is injected into the exhaust riser. This area, where warm water hits very hot exhaust gasses is a common source of scale build-up.

View attachment 48325

Depending on where you sail, that elbow buildup can also be flashed cooked bio goo. Opening up and then cleaning out that elbow was second to replacing holding tank hoses as far as awful and unforgettable smells. Maybe it was worse... Wear gloves. If any of that liquid gets on your skin it will linger for hours if not days and no amount of scrubbing seemed to touch it.

 

[AlanO]

When the mechanic changed the coolant and checked the freshwater side of the system, I also had him check the heat exchanger and he determined it was in good shape as was the zinc. Ideally, I would have done that work myself, but time was running short for a planned cruise.

Christian's video is helpful, but not definitive. I think the volume emitted we have is somewhat less.

I'm hoping a constriction at the injection point like Ken's photo is the culprit and I can avoid removing the elbow for a clean-out (better outcome) or replacement (worse outcome). My plan is to first remove both the raw water hose at the injection point and the exhaust hose to inspect the elbow. I'm hoping that will be definitive on whether I need to remove the elbow, which becomes a bigger job.

 

[Christian Williams]

I don't know how anybody can inspect a heat exchanger in place, except for obvious leakage. If there is no history of recent acid washout, that would be the first thing I'd do.

 

[Joliba]

AlanO,
What year and model Ericson is your boat?
It is likely that precipitate build up in the heat exchanger and carbon and corrosion narrowing the exhaust elbow are both present if these have never been addressed by any previous owner. I agree that the easiest place to start is the heat exchanger. If you opt to tackle both, everything, including hose replacement will be more easily accessed with the exhaust elbow removed.
I also replaced the vent hose to the exhaust at the transom with a vertical hose and one way valve as a vented loop.
Mike Jacker

 

[Pete the Cat]

When the mechanic changed the coolant and checked the freshwater side of the system, I also had him check the heat exchanger and he determined it was in good shape as was the zinc. Ideally, I would have done that work myself, but time was running short for a planned cruise.

Christian's video is helpful, but not definitive. I think the volume emitted we have is somewhat less.

I'm hoping a constriction at the injection point like Ken's photo is the culprit and I can avoid removing the elbow for a clean-out (better outcome) or replacement (worse outcome). My plan is to first remove both the raw water hose at the injection point and the exhaust hose to inspect the elbow. I'm hoping that will be definitive on whether I need to remove the elbow, which becomes a bigger job.

If he is a competent mechanic and checked the heat exchanger, I would be looking at the exhaust elbow. Some folks claim to be able to clean them, but my experience is that once they are clogged with the black onyx stuff you will probably have to replace it rather than just clean it. It is also possible that if the PO ran the engine at low speed and under very light load, the exhaust manifold can get plugged I have seen this recently on a friend's boat. But I would point you to the exhaust elbow given your information. It is also possible that you have one of those grates on the engine intake outside of your hull (Ericson did this on several of their models) that it might be somewhat restricted--because the boatyards often fail to remove, clean and paint the inside of the grate. But I would go for the exhaust elbow first.

 

[AlanO]

Thanks to all for responses. We replaced the coarse grating at the raw water intake at the time of purchase. It seems like a good method to keep plastic bags or kelp from getting sucked into the intake.

The yard mechanic seemed very competent, so I'm not ready to disregard his judgement just yet. Like a lot of boat troubleshooting this is a process of elimination. The next low hanging fruit is the exhaust elbow and pulling off a few hoses should be relatively simple and revealing. If I need to pull the elbow I might as well pull and check the heat exchanger at the same time for my own edification.

 

[Joliba]

If you do clean out your heat exchanger, there are several methods. Some people take it to a shop to be steamed, some boil it in water (I’m not sure how that works), and we followed a mechanic’s advice and soaked ours for a day in a vat of CLR. The CLR worked very well. We repainted it with engine paint, taping off all of the openings before reinstalling it with fresh gaskets and an anode.
Mike

 

[Christian Williams]

Yes, it has to be acid washed. Various acids work. Here's one product which uses phosphoric acid solution:

 

[AlanO]

An update on my progress....

I could not effectively inspect the elbow in place after removing the hoses so I removed the exhaust elbow yesterday from my Universal 5432. While there is a fair amount of internal corrosion, my inclination is that there is not enough to restrict the raw water flow into the exhaust that would explain my overheating issues. I have also inspected the anti-siphon T-fitting and there is no restriction. Photos are below with insulating wrap removed. At my next visit to the boat I'm going to finish removing the heat exchanger for inspection.

All of the threaded fittings, except at the flange are seized. Perhaps with more doses of penetrating oil, a better bench vise, and a larger pipe wrench with more leverage, they can be loosened, but I am wondering if this would be worth the effort? It seems like I have a few options 1) Re-install it as is (perhaps not the best option); 2) try to disassemble and clean it up myself (could be a frustrating exercise); 3) take it to a machine shop and see if they can disassemble it and clean it up; 4) buy a new equivalent elbow and fittings for a new install. At a minimum I think I would have to remove the 90 degree brass fitting (also seized) to adequately clean out the mixing elbow, but perhaps the remaining could be left in the seized condition and just cleaned up on the outside. Based on the photos, what do folks suggest?

Is the color of the gasket typical or symptomatic of other issues? I don't believe there was any exhaust leakage at the joint. Regardless, the flange gasket will need to be replaced. Can anyone point me to an online supplier?

Thanks.

Alan

 

[Joliba]

Been there, done that with the identical engine and exhaust installation. My advice, replace the flange, riser pipes and mixing elbow with new ones… It’s time with a system this old, and you won’t regret it. More than half the battle is the removal that you have already done.
Mike Jacker

 

[Joliba]

I believe the elbow is an Onan 155-1058 which may be $150 online. You will need to do some pipe step downs and custom fitting which should be easy at any local plumbing supply business. You simply need to use the old existing system as a model.

 

[Christian Williams]

..and when you have the heat exchanger off, acid wash it ("boil it out"). This is done by immersing it in acid, such as Barnacle Buster, so deposits inside are dissolved away. I believe in the acid wash even if the guts look OK. I am told there can be a smooth buildup in the internal tubes that isn't visible by casual inspection.

Lots of how-to here and on YouTube.

 

[Pete the Cat]

I agree with Christian and Mike. Seems like you are headed toward your heat exchanger as the culprit, but replacing the pipes and the elbow is probably a good idea while you are in there.. I can't really judge the gasket from the picture, but you need to just put it back together with very clean mating surfaces and a very light coat of high temp RTV on the new gasket (which you can easily make yourself from exhaust gasket material from a car store). I seem to see galvanized pipe was used in this exhaust system (is that right??) I believe you want to replace that with black iron pipe--and sometimes you can get this at Home Depot or have a pipe shop make it up. If the old stuff was galvanized, it should not have been used--I am told the stuff can produce very toxic gasses at exhaust temperatures. Black iron pipe does not.

 

[Joliba]

Alan,
The exhaust flange gasket should be part number 298600 at Westerbeke.com

 

[Joliba]

Here is the link:

GASKET - Westerbeke

GASKET

www.westerbeke.com

 

[Kenneth K]

When I was at this stage in the process, I rebuilt my exhaust system with stock stainless steel plumbing fittings and a Yanmar-type exhaust elbow.



Details here: https://ericsonyachts.org/ie/ubs/ma...r-elbow-replacement-with-support-bracket.541/

 

[AlanO]

Thanks for the responses. Yes, I think I am headed towards boiling out the exchanger, regardless. That makes sense following the effort to take it apart. The flange appears to be newer than the rest of the elbow and can be re-used. The rest of the elbow and gasket I plan to replace. Good advice on avoiding galvanized pipe. Is there anything critical about the riser length (flange to elbow)? Currently, the 90 deg brass fitting juts up right against the top of the engine box. I am considering making that a half inch or inch shorter so it fits better and easier to work on.