SailNet Community banner

1 - 9 of 9 Posts

·
Registered
Joined
·
253 Posts
Discussion Starter · #1 ·
I have a 1985 Universal M-18 and send oil out for analysis on every change. The most recent analysis indicated glycol in the oil.

I haven't noticed a decrease in coolant, increasing oil, or bubbles in the overflow
so the issue is probably small.

I pulled and rebuilt the exhaust riser this winter after discovering a leaking exhaust flange gasket. Maybe far fetched but I could imagine how a pressurized freshwater loop might leak past the exhaust flange and back into the engine. Hoping this fixes the issue.

Another culprit might be the exhaust manifold gaskets. I noticed potential puffs near the exhaust gaskets when there was spilled coolant burning off after bleeding the freshwater loop.

Of course this could be a head gasket issue.

Current plan of attack is:

1. Buy/rent a block checker and see if exhaust gasses are present in the manifold

2. Retest oil after riser rebuild

3. Keep oil clean with short oil changes (10-20 hours)

4. Replace exhaust gaskets

5. Replace head gasket (would do intake and exhaust gaskets if not done before)

Any other thoughts might be helpful. After reading the service manual, a head and other gaskets seem doable.






Sent from my iPhone using Tapatalk
 

·
Banned
Joined
·
8,867 Posts
I have a 1985 Universal M-18 and send oil out for analysis on every change. The most recent analysis indicated glycol in the oil.

I haven't noticed a decrease in coolant, increasing oil, or bubbles in the overflow
so the issue is probably small.

I pulled and rebuilt the exhaust riser this winter after discovering a leaking exhaust flange gasket. Maybe far fetched but I could imagine how a pressurized freshwater loop might leak past the exhaust flange and back into the engine. Hoping this fixes the issue.

Another culprit might be the exhaust manifold gaskets. I noticed potential puffs near the exhaust gaskets when there was spilled coolant burning off after bleeding the freshwater loop.

Of course this could be a head gasket issue.

Current plan of attack is:

1. Buy/rent a block checker and see if exhaust gasses are present in the manifold

2. Retest oil after riser rebuild

3. Keep oil clean with short oil changes (10-20 hours)

4. Replace exhaust gaskets

5. Replace head gasket (would do intake and exhaust gaskets if not done before)

Any other thoughts might be helpful. After reading the service manual, a head and other gaskets seem doable.

Sent from my iPhone using Tapatalk

I haven't noticed a decrease in coolant, increasing oil, or bubbles in the overflow
so the issue is probably small.
You may be right. If the analysis shows a heavy concentration, maybe it is a concern. If you are not loosing a lot of coolant, not blowing white smoke & it runs "all right", it may not be worth tearing into it?

Some years back I had a VW diesel. In really cold weather coolant would weep at the head/block gasket. As soon as it warmed a bit, the seepage stopped. The seepage was barely visible. Perhaps the iron block & aluminum head combination, expanding/contracting at different rates, caused it. Anyway, I did nothing about it & it ran its little heart out almost forever.

Paul T

Forgot this: If you suspect head gasket problems, perhaps re-torqueing the head bolts, to spec, could be tried before taking the head off?
 

·
Registered
Joined
·
4,023 Posts
If it is a cold leak, as Paul suggested, it may not repeat all summer, but be there in the Spring. If it is not there in the Fall, Paul's suggestion of benign neglect has merit, since chasing down the leak will be tough.
 

·
Registered
Joined
·
4,985 Posts
Another possible source is the cooling water pump. Its usually driven directly (not by a belt like the raw water pump usually is) and can leak coolant into the engine if the seals fail. Most (but not all) pumps have a weep hole between the two seals to detect a leak.

If the oil looks and remains normal (i.e. black not gray), I would also vote for just carefully watching things and not tear the motor apart at this point.
 

·
Banned
Joined
·
8,867 Posts
Another possible source is the cooling water pump. Its usually driven directly (not by a belt like the raw water pump usually is) and can leak coolant into the engine if the seals fail. Most (but not all) pumps have a weep hole between the two seals to detect a leak.

If the oil looks and remains normal (i.e. black not gray), I would also vote for just carefully watching things and not tear the motor apart at this point.
I don't know "how much is too much"? Maybe the oil analysis company can tell how much is in the oil? My experience was with a Continental flat head six that leaked at the head/block surface. The leak was bad enough that the anti freeze
seeped down into the piston rings and stuck them, causing a big drop in compression. Also, blew a lot of white smoke on start up which would finally clear up until the next start up.

The problem developed when we were a long way from home so we decided to try to nurse it in. Messy job when we got it home & apart.

Paul T
 

·
Registered
Joined
·
26 Posts
Can I inquire (over a year later) Is there a lab that is preferred by SailNet members??

From online searches it seems that as important as it is purported to be, there is little information on how to start getting oil analyzed.

Having just purchased a GOB, I would like to get a baseline on this 1982 Perkins 4108 that was said to have only 300 hours since overhaul.

I would appreciate any tips as to which direction to point before shooting oil samples via mail or UPS.
Thanks.
 

·
Registered
Joined
·
26 Posts
oops. I see from other threads that there are shops, like a Cat repair facility that will do it.
I assumed that it would be a special lab that aviation and other expensive shops used.

No need to reply. I think I can take it from here.
 
1 - 9 of 9 Posts
Top