SailNet is a forum community dedicated to Sailing enthusiasts. Come join the discussion about sailing, modifications, classifieds, troubleshooting, repairs, reviews, maintenance, and more!

Oil Analysis

1654 Views 8 Replies 6 Participants Last post by engineer_sailor, Aug 25, 2015

engineer_sailor

Discussion Starter · May 6, 2014

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

See less See more

Save

1 - 2 of 9 Posts

dabnis

· #2 · May 6, 2014 (Edited)

engineer_sailor said:
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?

Save

dabnis

· #6 · May 7, 2014

JimsCAL said:
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

Save

1 - 2 of 9 Posts

This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.

Top Contributors this Month