Perkins 4108 loosing coolant, another thread

[zoefzoef]

The exhaust has enough back pressure to induce air bubbles, i.e. exhaust gas into the heat exchanger on this particular engine. Depends on system design. RPM, other factors but it is possible. A crack in the exhaust passages of the manifold would do the same thing, put bubbles into the coolant.
No, the cooling system in under pressure. Exhaust fumes will not and up in de coolant. And otherwise the cooling system will run dry you would not see bubbles sorry.

And the rest of your comments... Sure
He has a leaking gasket. Period.

[Scubaseas]

Originally Posted by zoefzoef

The exhaust has enough back pressure to induce air bubbles, i.e. exhaust gas into the heat exchanger on this particular engine. Depends on system design. RPM, other factors but it is possible. A crack in the exhaust passages of the manifold would do the same thing, put bubbles into the coolant.
No, the cooling system in under pressure. Exhaust fumes will not and up in de coolant. And otherwise the cooling system will run dry you would not see bubbles sorry.

And the rest of your comments... Sure
He has a leaking gasket. Period.

Hard to say the cooling system is under pressure when the cap is off. Read his posts. I question your logic tree sir.

[Scubaseas]

Originally Posted by zoefzoef

The exhaust has enough back pressure to induce air bubbles, i.e. exhaust gas into the heat exchanger on this particular engine. Depends on system design. RPM, other factors but it is possible. A crack in the exhaust passages of the manifold would do the same thing, put bubbles into the coolant.
No, the cooling system in under pressure. Exhaust fumes will not and up in de coolant. And otherwise the cooling system will run dry you would not see bubbles sorry.

And the rest of your comments... Sure
He has a leaking gasket. Period.

If you need to be right, you're right. He WAS losing coolant. It also appears that fixing the endcaps solved his overheat, coolant loss and bubbles issue. What do I know? Seems to be fixed regardless of the diagnosis.

[gregfreed]

4108’s will loose coolant consistently if you have not installed a vapor recovery tank.
If you are actually getting bubbles, my first thought would be head gasket.
If you have a carbon monoxide alarm onboard, try putting it near the bubbles and see if it responds

[Scubaseas]

Better use the chemical through the liquid in the bottle one.

Bubbles in the coolant is indeed a sign of a bad head gasket. There are usually other signs too. I would not take the head off on one out of three signs or symptoms. But your boat do your thing.

It will look like you are loosing coolant if you over fill it when it's cold. It expands quite a bit on warm up. People fill it cold, run it up to hot and then the next day see it's down 19mm and assume it's low. Better to check when all the way hot. The "vapor tank" I presume is a coolant overflow tank? Fun fact they originally came into play because of hydrocarbon emissions believe it or not.

[gordonhinds]

Hi,
I am not a mechanic and know even less than you. I had three lots of mechanics service my Volvo penta md 40 which I believe is a rebadged Perkins (is that right) over the past 18 months.
I had a dreadful clunking noise at certain revs, and milky oil and was losing oil in the transmission. The engine seemed to run a bit hot. After a year of trying to find out what it was I demanded (having been dismissed) to pull the shaft out and check the prop thinking that may be causing the noiseI I had already renewed the skeg bearing. By pulling the shaft out (the mechanic wanted to cut it) we found the transmission oil water cooling system was shot. We also then found the exhaust elbow was shot (heavily corroded). The oil cooling in the transmission wasn’t working and so burning the oil. The cooling plate on the transmission was shot too and was part of the horrible noise at certain revs which also was a misalignment of the shaft to engine. I found an old but good condition cooling plate (Volvo don’t make them anymore), put a new elbow on, and now have a quieter exhaust/cooling system that works. The oil leak has stopped in the transmission.
I’d check all the cooling system, transmission included. Bubbling indicates air getting in. So mayba cracked head, but your oil is ok so maybe not?

[Scubaseas]

Originally Posted by gordonhinds

Hi,
I am not a mechanic and know even less than you. I had three lots of mechanics service my Volvo penta md 40 which I believe is a rebadged Perkins (is that right) over the past 18 months.
I had a dreadful clunking noise at certain revs, and milky oil and was losing oil in the transmission. The engine seemed to run a bit hot. After a year of trying to find out what it was I demanded (having been dismissed) to pull the shaft out and check the prop thinking that may be causing the noiseI I had already renewed the skeg bearing. By pulling the shaft out (the mechanic wanted to cut it) we found the transmission oil water cooling system was shot. We also then found the exhaust elbow was shot (heavily corroded). The oil cooling in the transmission wasn’t working and so burning the oil. The cooling plate on the transmission was shot too and was part of the horrible noise at certain revs which also was a misalignment of the shaft to engine. I found an old but good condition cooling plate (Volvo don’t make them anymore), put a new elbow on, and now have a quieter exhaust/cooling system that works. The oil leak has stopped in the transmission.
I’d check all the cooling system, transmission included. Bubbling indicates air getting in. So mayba cracked head, but your oil is ok so maybe not?

In the States but Sen-dure makes very good quality aftermarket replacement and universal heat exchangers, coolers, plates, etc. etc. if you need an alternative to expensive or no longer available parts. Not cheap but good quality and proper materials.
https://sen-dureproducts.com/


I can think of 4 ways to proof out a diagnosis of head gasket or head without taking the top of the motor apart.

[theglo]

Man, this thread got away since I last saw it. To whoever posted I need to get a mechanic, I’m good. Thanks though! That’s what cruisersforum and YouTube are for!

I was going to update this post when I arrived inGuadeloupe. Sailing tomorrow. It’s a 50 mile stretch. Today I motored HARDer than usual for about 7NM (total 2 hrs run time) and my engine didn’t reach what I used to regard as normal operating temperature. I think I can increase my RPMs to what others say they get on these engines. No overheating and no loss of coolant since I tested at the dock a few days back. Looking good.

I’ll update again in Guadeloupe.

Thx.

[Rob H]

Places where exhaust and Coolant can come in contact. #1 The exhaust manifold it self, being water cooled could have a crack. This would allow the pressure of coolant to drip into the manifold and be forced out with the exhaust.

#2 Where the mixing elbow is attached to the back of the exhaust manifold. Four of the threaded studs where the mixing elbow is attached screw directly into the water jacket on the Exhaust Manifold. I have a intermittent leak at this location that was extremely hard to detect, because it never drips. The coolant leaks past the threads of the stud. It never shows as a leak though because it only does it when running and the coolant evaporates off of the hot manifold. You can tell by the sweet smell of antifreeze evaporating.This is where the leak is on my 4108 and I have it apart now. I will reseal the 4 studs that secure the mixing elbow.

#3 is the Cylinder head and or Head gasket are last though I would go for the easiest (cheapest) to address first.

You could pressure test your cooling system to see if any antifreeze shows itself. Remove your mixing elbow to see if it is seeping past the threads of the studs like mine has.



Rob H

South River Edgewater MD

[Scubaseas]

Originally Posted by theglo

Man, this thread got away since I last saw it. To whoever posted I need to get a mechanic, I’m good. Thanks though! That’s what cruisersforum and YouTube are for!

I was going to update this post when I arrived inGuadeloupe. Sailing tomorrow. It’s a 50 mile stretch. Today I motored HARDer than usual for about 7NM (total 2 hrs run time) and my engine didn’t reach what I used to regard as normal operating temperature. I think I can increase my RPMs to what others say they get on these engines. No overheating and no loss of coolant since I tested at the dock a few days back. Looking good.

I’ll update again in Guadeloupe.

Thx.

Thanks to c.K. it sounds like you are good to go. Now all you need to do is swear off putting sealing stuff where it doesn't belong. Have a great sail.

[arcticmonkey]

I had same problem with my 4018... my fix was new head gasket... also gives you a chance to get to know your new best friend

[theglo]

Arrived in Guadeloupe. Unfortunately, the weather was spectacular and we sailed the 50Nm with less than an hour of engine time. No overheating and no loss of coolant.

Think all is well.


Thanks all!

[Scubaseas]

Spectacular weather is hardly unfortunate. There will be plenty of time later to give the engine a good test run. You have my envy. Still winter here in Maine.

And don't worry, there will be plenty of stuff that breaks in the future.

[rbk]

Originally Posted by theglo

Man, this thread got away since I last saw it. To whoever posted I need to get a mechanic, I’m good. Thanks though! That’s what cruisersforum and YouTube are for!

I was going to update this post when I arrived inGuadeloupe. Sailing tomorrow. It’s a 50 mile stretch. Today I motored HARDer than usual for about 7NM (total 2 hrs run time) and my engine didn’t reach what I used to regard as normal operating temperature. I think I can increase my RPMs to what others say they get on these engines. No overheating and no loss of coolant since I tested at the dock a few days back. Looking good.

I’ll update again in Guadeloupe.

Thx.

Just for your own personal information, if and when you get the opportunity throw a digital rpm gauge on the main crank pulley and check what your actual rpm’s are. Most 4108’s get their rpm’s from the alternator and depending on what has been replaced over the years can be 300-500rpm off. It gets better with newer externally regulated alternators like balmar but can still be off. Not that it matters too much but is good to know what your engine is actually running at.

[Icarus]

Originally Posted by theglo

There is a thread from the prior owner, @dneve, about my same coolant issue, back in 2017. Please help with next steps.



Problem: Engine is loosing coolant into the exhaust.



Diagnosis & things I’ve seen:

1. I filled the coolant tank up with descaler and noticed some soap like bubbles in the exhaust output. Out a few squeezes of joy dish soap in there to be sure and have suds coming out exhaust.



2. With coolant cap off, air is constantly bubbling out.



3. I checked mixing elbow, looks fine, new with prior owner 2017, a few hundred hours ago.



4. Heat exchanger brand new: prior owner had spare troubleshooting this in 2017.



5. Problem was manageable, maybe 6 ounces of lost coolant in an 8 hour run and I’d just top it off. Problem got noticeable worse when I tried to fix it the same way I think the prior owner did. I dumped in some radiator leak stop stuff. HOWEVER, as I am an idiot, I only got about half a bottle of that stuff in before realizing I needed to empty the tank a bit, then got distracted by my kids and only ran the engine for about 10 minutes before leaving that stuff in their to fester. Instead of solving the problem this seems to have exasperated it.



What I’m doing now:



1. I’m running a descaler in there at the dock (back at the dock in Antigua). I am hoping to clean out any wierd clumps I added. I then plan to do the radiator stop leak solution thing again, following the instructions better. As this worked for the prior owner for 3 years and I put hundreds of hours on the engine this year between FL and Antigua. I’m hoping that May at least get me back to where I was.



BUT, if that doesn’t work. What’s next? Anything else I should look at? Head gasket?



One thing that I don’t like is how close the tolerance is on the heat exchanger and the rubber end caps. I can barely get a hose clamp on there to keep the coolant out. I’ve redone them numerous times but if someone has a “foolproof” way to do that I’d be interested in hearing it.



Thanks from Antigua! I have a long way to get home so we appreciate the help.



Justin & family

SV Allora

Looks like a coolant leak at the water cooled exhaust manifold/reservoir.
That's what I would check before ripping off the head.
If you lose coolant it got to go somewhere if the oil is clear...take off the exhaust water trap and check if it has coolant in it.
You said the engine needs 1.5l of oil every 100 hours?
Something wrong there...