Losing Coolant

[Max Simmons]

Just got back from 3 day cruise over the holiday weekend. As SOP, checked oil, trans and coolant levels before leaving the dock. Starboard engine coolant level was low, which was a first. Topped off with about a quart to bring it back up to normal. Engine oil looks good, no milk or evidence under cap.
The exhaust/heat exchanger was pulled and cleaned approx 300 hrs ago and no issues. Water pump replaced 100 hrs ago.
There does appear to be some slight leakage at exhaust elbow, but looks more like raw water side, but am leaning towards pulling and inspecting this as possible culprit, but am wondering if you typically put the fresh water side under pressure and find leaks?

 

[DavidM]

I was having a similar problem on my Yanmar 6LY 370 hp engine. I first went through and tightened everything that I could and looked for leaks. Couldn't find any leaks but the problem continued.

So I borrowed a radiator test kit from my friendly Autozone store and pressured the system up to 15 psi. I immediately found a hose that was leaking underneath the clamp. I thought I had tightened it, but I tightened it some more and the leak stopped. It then held pressure 15 minutes.

Problem solved.

Tell us which engine though.

David

 

[Xsbank]

What engine do you have? Do you have an overflow bottle? More info needed.

 

[Max Simmons]

Perkins 135 with Manicooler (combo exhaust and heat exchanger) . No overflow bottle.
No issues in 10 years I've owned the boat.

 

[Xsbank]

I'd say a quart is not an issue but I'd watch it like a hawk. I haven't had a manicooler but they are quite exotic.

The water in coolant evaporates, when the coolant gets old it is subject to cavitaion which can blow coolant overboard (you didn't say if you have changed the coolant in those 10 years) and then there is the list of failures, but I'm a believer in "simplest first." Is it old coolant?

 

[CaptSteve53]

Fully agree with the Coolant change-should done every 2-3 years as it become acidic and eat away the numerous Aluminium parts and other metals,

Below is a not to old manifold of a Volvo that didn't change there coolant for three years (two of them sitting un used).

Guess where it was leaking???

Cheers Steve

 

[sunchaser]

Assuming the coolant leak is with the Perkins mani cooler, it is usually a warning sign. If confirmed suggest you locate a new manicooler and swap it out. How old is the engine and is this the original, if over 25 years you've done pretty good.

 

[Max Simmons]

Hope it's not a Manicooler issue. Pulled this one off a couple years (5?) back and had it cleaned and pressure tested, all was good. Read enough about these that I do not want to be searching for a replacement. They are original, 33 yrs young and 2,600 hrs.
Replaced coolant 3 yrs ago when I added block heaters.

 

[Irish Rambler]

If you've a mind to, take off the heat exchanger (manicooler) take it to a radiator repair shop and get it refurbished.
Alternatively if you've hands on you take it off, block off one end, fill it with 12% vinegar, block of the other end. Drain it after 24 hrs and flush with fresh water. Look inside, if its sparkling clean pressure test it, if it fails the pressure test press out the core, remove the 'O' rings replace and test again.
If its still got traces of calcium/crud on the tubes repeat the cleaning procedure with vinegar and retest.
Once it's passed, refit with new gaskets and after a run to normal engine temp 90 c then torque up the retaining nuts again.
Always leave space in the header tank for the water to expand when hot.
If its faulty and you need a replacement contact Bowman.co.uk the OE suppliers for Perkins, they ship fast and worldwide.

 

[Dwk]

Wondering the cause, fix, and outcome of the situation ,having the same problem with coolant with similar circumstances.

 

[Duvie]

3.6544T Perkins

I have noticed after servicing the multicooler and manicoolers on the 200 hp motor that after a Winter layup I had lost coolant. Bolts loosened and needed to be retightened on the exchangers. I have had this happen more than once over the winter.

 

[normandawn1]

Had a similar problem on my 20 year old motors. The marinisation was done by Diecon all steel construction and galvanised.
Chased the problem for a while and then discovered that the exhaust manifold had corroded into the heat exchanger tank. You can check by taking off your exhaust hose after sitting for a while (if wet exhaust)and checking for green coolant.
We rebuilt the tanks to solve the problem.

 

[twistedtree]

I think DJMarchand's advice is the best next step. Put a pressure tester on the coolant system, pump up to 15 psi, and check for leaks. The system has been worked on a bunch recently, so it's probably nothing more than a hose clamp that needs to be tightened. I've been amazed at how quickly and clearly leaks will show themselves when you pressurize the system. When running, the heat of the engine tends to burn off small amounts of leakage, so it goes unnoticed.

 

[Gdavid]

Wondering the cause, fix, and outcome of the situation ,having the same problem with coolant with similar circumstances.

Had the same problem last year with a 200 perkins in a Mainship 34. Turned out to be the long tub bundle within the manicooler. Disassembling the end caps and cleaning them up was the hardest part of the job. The bundle itself was readily available from TAD.

 

[fgarriso]

Pressure test @15psi is the best place to start. If you loose any pressure check all hoses and connections.
If you still have a pressure loss check the heat exchanger.
If no luck call an engine tech to check for WP, head gasket, or freeze plug leaks.

BUT one quart of 50/50 coolant is not a big deal. Run the motor for 4-5 hours under normal load shut it down to cool, and check coolant again.

If you are still loosing coolant the break out the tools.

 

[twistedtree]

A number of people have suggested that loss of quart of coolant is no big deal. I would disagree, and consider it a really big deal. Not necessarily an immediate emergency, but absolutely a problem that needs to be fixed. A correct functioning cooling system should have zero coolant loss. Zero.

 

[fgarriso]

A number of people have suggested that loss of quart of coolant is no big deal. I would disagree, and consider it a really big deal. Not necessarily an immediate emergency, but absolutely a problem that needs to be fixed. A correct functioning cooling system should have zero coolant loss. Zero.

I agree, but my point is loosing 1 qt. out of 5 gal. is not that big a deal if it is a ONE time thing. If it happens daily then I would be VERY concerned.

 

[Dwk]

After checking and all hose connections in the coolant circuit I discovered a loose connection at the hot water heater coolant fitting that I didn't secure after winterization, absolutely my error.

 

[Gdavid]

After checking and all hose connections in the coolant circuit I discovered a loose connection at the hot water heater coolant fitting that I didn't secure after winterization, absolutely my error.

That will make your weekend much more enjoyable. Congrats.

 

[twistedtree]

I agree, but my point is loosing 1 qt. out of 5 gal. is not that big a deal if it is a ONE time thing. If it happens daily then I would be VERY concerned.

OK, we might be saying the same thing. I agree that a loss of 1 qt isn't going to shut down the engine, or otherwise impact operation. So in that respect, not a big deal.


However if a quart goes missing, even once, it went somewhere where it shouldn't and is a conclusive indication that something is amiss. Tracking it down, and even getting it to repeat itself can be maddeningly difficult, but you can be confident that something is going on. Many people may just live with a small, slow loss - your choice - but it's going somewhere. Personally I like to track such things down, even if it takes a long time. Small problems only get worse, never better, so I prefer to head them off. I chased a slow leak in my Deere engine for several years, so I'm no stranger to hard to find leaks. They suck.

 

[Irish Rambler]

At least David your man enough to admit your mistake, if anything it makes us even more meticulous to make sure we don't do it again.

 

[FF]

After a coolant R&R there can be air pockets in the engine & cooling system.

A long run usually gets rid of them , so perhaps there is no coolant "loss" ?

Next long run will tell.

 

[kapnd]

OK, we might be saying the same thing. I agree that a loss of 1 qt isn't going to shut down the engine, or otherwise impact operation. So in that respect, not a big deal.


However if a quart goes missing, even once, it went somewhere where it shouldn't and is a conclusive indication that something is amiss. Tracking it down, and even getting it to repeat itself can be maddeningly difficult, but you can be confident that something is going on. Many people may just live with a small, slow loss - your choice - but it's going somewhere. Personally I like to track such things down, even if it takes a long time. Small problems only get worse, never better, so I prefer to head them off. I chased a slow leak in my Deere engine for several years, so I'm no stranger to hard to find leaks. They suck.

I agree too!
Careful monitoring of all your engines systems is the key to early detection of problems that are about to occur.
That lost quart is a warning sign, next trip it might turn into a gallon or two, or all the coolant, and result in a disastrous overheat situation.
Overheating a diesel is the #1 killer!

 

[ctjstr]

Lots of bayliner folk with hino diesels are very familiar with manicooler issues. Be thankful its not the issue. I've actually fixed a manicooler before, to avoid the cost of a replacement. it was a booger. cut a couple large holes in the casing, so i could get access to the exhaust tube inside. Was able to tig weld the crack in the exhaust tube, then weld the large holes back together. It took a bit, but ended up working fine and saved me over 3 grand. Had it ceramic coated when done, which is not a bad thing to do on those coolers any time. Also helps to make certain the seals do their job of completely isolating the cooling bundle from the housing as you put it back together. Have fun.