Intermittent Grinding Noise from Engine

[jamescyu]

Hi. I need some help here from you engine experts. This Spring I changed oil and filter of my 2GM20F diesel. I unintentionally overfilled the crankcase (about 1/8" above the high mark of the dip stick) and did not think much about it. Today I took the boat out, it ran fine as usual, But when I pull her into the marina after about two hours running, I heard this intermittent grinding noise from the engine. After I docked the boat, I checked the engine compartment and noticed some small oil splash/spots on the compartment floor and wall. I checked the oil with dip stick and found it right on the high mark on the stick and oil looks clear. There is no oil marks on the engine except the back of the alternator (I felt there by hand and got my hand smudged with black oil). I ran the engine in idle and then in gear again. The intermittent grinding sound is surely there. But I could not pinpoint where exactly it was from. I did not notice any oil leaks or splash either. When I got home, I looked up the owner's manual and the service manual of the 2GM20F. But could not find anything definitive. I wonder if this is indicative of a failed oil pump and/or some seals. Any insight would be appreciated. Thanks

Jim

 

[Charlie13958]

Could be a number of things. Check oil level in transmission. Is noise from alternator, or water pump?

 

[Ken13559]

did you change the luboil filter? is it the right filter? is there any oil getting into the filter? i cannot imagine a slightly high level causing problem. got to be somethingelse.

 

[jamescyu]

Thanks for the replies. I know it was not from the alternator or water pump. It sounded as if it came from somewhere in the direction aligned with the starter motor (I was wrong to have said in my prior email that the back of the alternator had oil smudges. It was the back of the starter). But I could not pinpiont it. I have not checked the transmission lub. The filter is the right one but I have not checked to see if oil gets into the filter. Will do the filter and transmission lub tomorrow. I just hope this will not lead to a $$$ repair job.

Hi. I need some help here from you engine experts. This Spring I changed oil and filter of my 2GM20F diesel. I unintentionally overfilled the crankcase (about 1/8" above the high mark of the dip stick) and did not think much about it. Today I took the boat out, it ran fine as usual, But when I pull her into the marina after about two hours running, I heard this intermittent grinding noise from the engine. After I docked the boat, I checked the engine compartment and noticed some small oil splash/spots on the compartment floor and wall. I checked the oil with dip stick and found it right on the high mark on the stick and oil looks clear. There is no oil marks on the engine except the back of the alternator (I felt there by hand and got my hand smudged with black oil). I ran the engine in idle and then in gear again. The intermittent grinding sound is surely there. But I could not pinpoint where exactly it was from. I did not notice any oil leaks or splash either. When I got home, I looked up the owner's manual and the service manual of the 2GM20F. But could not find anything definitive. I wonder if this is indicative of a failed oil pump and/or some seals. Any insight would be appreciated. Thanks

Jim

 

[kloudie1]

Errant crab pot??
seriously, check transmission oil level and see if it is black or full of fine metal.. Could be a bad adjustment of the shift lever .. It doesn't sound like something related to a slight oil overfill.. especially if the oil pressure alarm is not howling..

 

[Ken Palmer]

I had something similar happen last year on my H33.5 with same engine. We were cruising when I heard this awful metal on metal grinding noise. Couldn't locate the source after checking the engine and transmission with a stethoscope. The next morning in port I had the boat hauled. As soon as I saw the prop shaft I found the problem. The zinc that is clamped to the shaft had come loose and was hitting the strut when I was in gear. I replaced the zinc with a new one and everything worked fine afterwards. I hope your problem is simple to fix like mine. It might pay to dive on the boat and check the zinc.

 

[jtm]

james- seems like the easiest thing to do is go over the side and feel out the zincs on the shaft- I suppose you have "two" forward of the prop strut. I'd use garden gloves as there could be some shells or some sharp metal edge that you could slit up you fingers on. But I don't think that you hurt the tranny with that little extra fluid- I've read that too much can blow you seals - but you said that the tranny fluid as at the same level- so I don't think you're losing it in the tranny. Also you may want to take a second look at your upper center pulley- if its wobbly in it its position - it could be you culprit and it is throwing stuff- like antifreeze comingled with the engine oil onto the starter. That pully pumps you internal cooling system and it has a shaft that can crack- I suspect this is the issue- about 3 years ago my pulley shaft broke and the pully was still in the bushhing and turning but essentially working its way out of the bushing-

BTW- the replacement part at about $175 - but an easy DIY.

 

[Benny]

I don't think your grinding problem is related to the oil overfill. If you feel it is coming from the starter then remove the starter, check it and test it. The gear that engages the flywheel may not be retracting fully and thus grinding against the flywheel. Alternator and water pump bearings also make grinding noises when they start to fail. Noises travel through metal on an engine so the use of a stethoscope is sometimes the best way of tracing the source of an engine noise.

 

[jamescyu]

Hi jtmccue,

I checked the center pulley this morning after removing the belt from it. It had a lot of lateral play and when I push it sideway the anti freeze leaked out. But I could not removed the pulley and shaft. You mentioned that you had a similar experience. Did you ordered the whole fresh water pump assembly?? What do I need to watch out for if I am going to DIY?? Was it tricky?? Thanks again for the tip and in advance for you input.

Jim

james- seems like the easiest thing to do is go over the side and feel out the zincs on the shaft- I suppose you have "two" forward of the prop strut. I'd use garden gloves as there could be some shells or some sharp metal edge that you could slit up you fingers on. But I don't think that you hurt the tranny with that little extra fluid- I've read that too much can blow you seals - but you said that the tranny fluid as at the same level- so I don't think you're losing it in the tranny. Also you may want to take a second look at your upper center pulley- if its wobbly in it its position - it could be you culprit and it is throwing stuff- like antifreeze comingled with the engine oil onto the starter. That pully pumps you internal cooling system and it has a shaft that can crack- I suspect this is the issue- about 3 years ago my pulley shaft broke and the pully was still in the bushhing and turning but essentially working its way out of the bushing-

BTW- the replacement part at about $175 - but an easy DIY.

 

[jtm]

call Mack Boring in Edison NJ with your engine model and maybe the s/n-they will know the part- I think there may be a gasket- if not you can use some permatex formagasket - its an easy DIY- you will cannicalize the pulley wheel and reaffix to the new housing's hub- don't over torque/tighten the bolts- its aluminum an softer metal- just snug 'em up. and use a very slight dab of antiseize on the threads

 

[jtm]

As it happened I went to Mack Boring today- and sorry, Its not in "Edison" NJ but "Union" NJ
I must have had a senior moment.

 

[jamescyu]

Thank you for all the helpful info shared. I finally got the boatyard at where I keep my boat to do this for me. I replaced the fresh water pump, flushed the cooling system and changed in/out hoses for the sea water and fresh water to the cooling system. Just got back from my boat. Tested everything and the engine runs fine and hopefully I'll have this summer trouble free for my engine. Again thanks for all the help from you guys.

Jim

 

[Steve Dion]

Jim:

So the problem was the recirculating pump, not the raw water pump? If this is the case, it is one of the first ones that I have heard anyone changing.

I am glad you got her fixed. These problems can be un-nerving. It was a good idea to change out those hoses. This should give you many years of trouble-free operation.