New Engine - Same 4.107 over heating problem.

[joesail]

Greetings engine experts. I have a puzzle for you and hell I'll even offer a prize if anyone can help me. If you don't want to know the back story skip to the bottom and read Current Situation section.

Let me start by admitting that I purchased my Gulfstar G41 Motor Sailer in 2011 without a real survey. Knowing nothing about diesels at the time I should have known there was problem during the sea trial when the PO didnt want to run the engine over 2000 RPM. What I quickly discovered after the sale was was that at 1600 RPMs the engine would over heat.

I do have experience working on and building muscle cars in my early years so I went to work troubleshooting the possible causes. I called every boat expert I could find and every one of them gave me things to test but I could find NO REAL smoking gun. I eventually had the areas most experienced marine diesel mechanic diagnose the issue. His diagnosis was "either its the head or cylinder wall. Pull it out and rebuild".

At this point I had already spent close to 2000 trying to find the cause so I bit the bullet and and ordered a factory reman complete engine from Foley Engines in 2014.

The boat sat on the hard until I had a professional put the engine in and start it up sometime in 2016.

Now here is the rub...... I have replaced virtually EVERYTHING and I still have temperature control problems with the new engine.

1. New Engine complete with new alternator
2. New water pumps (165 degree thermostat)
3. New strainer
4. New exhaust, mixing elbows, and vernalift muffler
5. Reconditioned BOWMAN combined heat exchanger
6. New Oil cooler
7. new prop, prop seal, cutlass, shaft (12" prop selected by Michigan Props)
8. New Presep air filtration
8. Even had the tyranny rebuilt during the repower


I splashed the boat and I'm using it regularly with an eagle eye on the temps. I use my laser temp guage to check temps too. I have improved RPMs but I still cant run the engine at WOT without temps exceeding 175 degrees.

Current situation
1. New Reman with 20 hours on it & has never been run hot
2. Engine was out of warranty before it was ever started (crap)
3. Observed bubbles exiting from radiator over flow tube within 2 minutes of a cold start. Engine not even at operating temp yet.
4. I can run the engine all day long at 2000 RPM / 175 degree temp
5. Pushing the engine over 2000 RPM for more than 5 minutes starts to raise temp over 175.

See a video of the temps and bubbles here


Once again am back to head problem or cracked cylinder? Am I the one unlucky guy who gets a defective engine from the factory. Still no water in the oil or oil in the water.

OK let the education begin......

[sailorchic34]

With the engine cold remove the coolant cap and start the engine. If you see bubbles coming up then you have a blown head gasket on the new engine. Which sort of means the rebuild was less then adequate.

If the bubbles in the coolant res. continue then it has to be a head gasket or shudder a cracked block.

Also check the the t-stat is the correct temperature and working correctly.

[Lepke]

How hot is hot? Where do you stop the temperature rise? At WOT is should raise the temp. WOT is not the continuous rating. About 80-90% of WOT is the usual continuous rating in most diesels.
It's common in some diesels to form bubbles on the cylinder water jacket at full power. Called cavitation in the engine, it's controlled by a coolant additive. I have to use it in my Ford truck.

Just ran my 4108 generator @ 1800. Couldn't make bubbles at near full electric load (20kw) and also driving my watermaker pump, temp at 180°.

[slowpoker]

Any hoses pinched? Those hoses are new? ( sometimes they delaminate inside)
Temperature gauge itself accurate, (besides the laser beam probe you have)?
Sometimes the heat exchangers are undersized, specially the non-Bowmar type so don't despair yet.
Same temperatures whether at idle or in gear, even at the dock?
Check coolant level and also consider an air bubble in the system somewhere in the hoses or water heater since you just had the system refilled.
Take a look at the exhaust when running cold and then when hot; check for flow and also look for steam. Steam (white) does not linger in the air as oil burning (black) would or fuel droplets, (also white); look for wisps of steam to determine if head and block are OK.
Thruhull and Seacock for raw water clear from marine fowling? Strainer clean?
Must be something simple like not enough cooling water going to cool the exchanger or the engine itself.
Good luck and let us know what you find.

[Jacko]

Joe sail Just a thought >>>>> seeing you have this problem on the old motor and the rebuild I was thinking you might check the size of your through hull and hose size for cooling water supply. You should be able to get specs from your manual, even though you are seeing water flow through the engine it maybe not enough. God luck

[Diesel Bill]

You mentioned a remanufactured heat exchanger. Any chance the gaskets or end cap are installed wrong where the cooling water is bypassing the tube core or part of the core. Is the outer core of the exhaust manifold cool to the touch under load and the water injection to the exhaust elbow cool/cold indicating good water flow. Check sea water impeller to verify it hasn't lost any vanes since initial start up. Like Lepke said, some diesels will make bubbles around the cylinders under heavy load. Cavitation as the cylinders expand and contract during power stroke impulses. Like Sailor Chick said, I hate to say the word (head gasket?)
Is the new prop pitched right for the boat engine combination?
We have to assume (big mistake) the engine was properly assembled, I hope. I once bought a remanufactured engine and the rods were resized improperly and ate the journals on the crankshaft. Hey . It happens. Another engine was put together with the camshaft improperly timed to the crank. Hey. It happens. Hmm. What else can we come up with. Check the through hull for the raw water intake. No squidlys hiding in there. Man, my brain is tired. Got to go to the boat early tomorrow morning. Left a pack of hotdogs in the fridge from Memorial Day and turned off fridge. Only 85 mile drive. Boo Hoo. Damn. I hope all of us gear heads can figure this one out.
I'll check back Sunday to see who won the lolipop.
Oh, I almost forgot, Is the heat exchanger plumbed up properly? I've seen them with flow opposite and with flow in same direction as medium being cooled.
All for now. Good luck.

[model 10]

41' motor sailor with a 12" prop? I don't think so.

[lancelot9898]

I have a 4-108 and a truck mechanic told me to use the heavy duty antifreeze like the big rigs use. I switched and found out that if you have wet cylinder sleeves then cavitation is occurring and heavy duty coolant helps. However, after making the switch I found that I have dry cylinder sleeves so the change was unnecessary. I routinely run at 180 degrees so to me that is not considered high. I did have a problem when changing coolant with a bubble forming in the system which allowed the temp to get around 200 at which time I shut it down. Getting rid of that bubble by adding more coolant while the engine is running at a high rpm solved the problem.

[donradcliffe]

If you're worried about bubbles in the coolant, run down to the nearest NAPA and pick their block test kit. It will give you a 10 lifetimes supply of a blue fluid which turns yellow if it is exposed to bubbles from a blown head gasket or cracked block.

[boden36]

Sounds like you have tried most things. Logic suggests that the problem may lie with one of the few things you have not changed.
Jacko's suggestion re he size of the raw water intake is good.
Is there any possibility that your hose runs allow an airlock in the coolant lines somewhere?

Regards,
Richard.

[jimbunyard]

Does the engine achieve max rpm in neutral?


The video doesn't play for me (not available).

[Mikado]

Hello,

I had a similar problem before and after installing a new (rebuilt) Perkins 6.314, I found out that the hose to the raw water pump was collapsed inside causing a restriction. It felt nice and soft from the outside so everyone involved assumed it was a good hose.

Good luck,

Jeff

[Symphony]

think simple first:
prop pitch
occluded cooling water supply

(although you may have to haul out to fix)

[Duet]

From prior experience if you read the Perkins installation manual you will note that Perkins limits the fore aft down angle to 17 degrees. In my experience more than this starves the forward end of the engine of cooling.
What is the static pitch of the engine off horizontal, i.e. while the boat is not being propelled? Does it overheat in this position?
What is the dynamic pitch of the engine and obviously the boat when moving at overheat RPM.

[model 10]

[QUOTE=Symphony;2406277]think simple first:
prop pitch




Yeah and how about that 12" propeller on a 41' motorsailer