Volvo Engine Rebuild ?

[svcattales]

I need some advice on engine troubleshooting and whether to rebuild sooner rather than later.

On our last cruise, our starboard MD2030B engine burned about 4oz of oil every 10 hours. I don't know the total hours on engine, but suspect it is close to 5,000. When I start the engine, I get about 1 minute of gray smoke but then all smoke disappears and engine seems to run fine. It starts quickly and seems to have the same power as the other engine. There is no fuel sheen in the water.

I sent off an oil sample for analysis and got a bad report. Wear metals aluminum (pistons) and chromium (rings) were very high. Likewise, contaminants sodium and potassium were high which indicates anti-freeze contamination. Report gave me a "critical" grade and recommended checking cylinder region and head gaskets. Other contanimation factors like soot, water, fuel, and oxidation were normal. Although the report was bad, is one oil analysis usually conclusive on problems?

Can you recommend any trouble shooting steps before I commit to a rebuild? Should the next step be removing the head and checking cylinder wear and head gasket? Appreciate your help.

[Stillraining]

Good question.

Normally the answer is no...one oil sample tells you very little really..However if you change your oil regularly and have fairly recently then it could be painting a fairly accurate picture..If I were in your shoes Id change the oil one more time and pull another sample at say 250 hours. or the same interval as is on the oil now...if that one looked better ..Id repeat..if it looked worse Id rebuild.

As far as the grey smoke for one min..some engines just run cold for a while till every thing expands and compression comes up everything tightens up and settles in...blue smoke would be indicative of piston rings or valve issues..white smoke is unburned diesel fuel from a myriad of reasons..anything from timing to a bent rod.

Smell the smoke...does it smell like diesel fuel or burnt oil...4 oz is allot for 10 hours...oil consumption by itself is not a high on the list reason for a rebuild if it still is starting easy and not polluting the water or air...loosing a bearing is...the metal in the oil my be from your bottom end not your top so pay close attention to the next oil samples numbers.

What were the Babbit metal readings?...Im sure they were normal or they would have said so.

[never monday]

all engines have wear metals, yours just happens to be higher than the statistical "norm"

looking at one oil sample is like looking at the front door of a house and fully describing the interior. I wouldn't worry about it until you had a half dozen or so similar reports. Or, the engine starts showing other signs of wear.

[Ex-Calif]

How often do you change oil?
hrs = ???
months = ???

How much do you use the engine?
hrs / mo?

I would be changing the oil every 100 hours or 6 months whichever comes first. Before the next couple of changes I would retest the oil.

I would monitor oil consumption and temps.

I would start savings boat bucks but would not panic. Depending on your usage you could get 1-2 more years out of it.

[svcattales]

Thanks for the great advice from Still Raining, Never Monday and Ex-calif. I'm not as worried about a major break down thanks to your wise inputs. I'll do an oil change and put some more hours on the engine and get another test sample. I'll also sniff the exhaust and check valve adjustment.

I was a little skeptical about the anti-freeze metals in the oil, when moisture content was normal. Since coolant is 50% water, i would expect to find both levels high.

Ex-calif, I had 140 hrs on the oil change and just returned from a 5 month, 1500 mile cruise. Just before the cruise, I switched to synthetic oil to get better lubrication on high-time engines. I changed filters at about 90 hours. The oil condition on test report was OK, but I'll change it and filter to remove contaminants.

I did have another maintenance issue on the engine during last cruise. The rubber caps on both ends of the heat exchanger have a inner clamp that keeps seawater flowing though 1.5" brass tube that encloses numerous copper tubes. The larger outer clamps attach to heat exchanger case. If I ran the engine at higher than 2000 RPM, seawater would leak around inner clamp and contaminate the anti-freeze. The extra pressure would force the anti-freeze/seawater out of the pressure cap on heat exchanger. I don't know if this is related to oil testing, because I believe the only place where oil and coolant could meet is around the head gasket. I do have a fix for this problem so hopefully the next oil test is better.

[sigmasailor]

Maybe it helps if you go back to mineral oil. I used to have an (older) MD7B I never gave anything else than (old school) mineral oil; I think that engine is still running.
The water from your coolant would evaporate leaving the other nasty stuff in the oil; didn't you have to fill up on coolant?
I would also give it a try before rebuilding an engine.

[Stillraining]

AH!....Changing to a synthetic may be your answer right there...Synthetic well get in an clean areas better then normal oils so you just may have effectively flushed out allot of residual metals laying in the engine..
Normally it is common to switch away from synthetic as an engine ages not switch to them due to the fact synthetics leak past seals easier.

[perchance]

Do yourself a favor and put your mind at ease. Either do yourself or have done a compression and leak down test on the engine. A competent mechanic can perform these simple tests in an hour. If you have a mechanic do it be sure and be there with him/her and ask questions You will be surprised at what you learn.

[svcattales]

Originally Posted by Stillraining

AH!....Changing to a synthetic may be your answer right there...Synthetic well get in an clean areas better then normal oils so you just may have effectively flushed out allot of residual metals laying in the engine..
Normally it is common to switch away from synthetic as an engine ages not switch to them due to the fact synthetics leak past seals easier.

I was wondering if there was a cause/effect in switching to synthetic. I just sent an oil sample in on my port engine and everything was normal including wear metals. Maybe there were some hidden areas of gunk on starboard that were "set free" with synthetic oil?

[svcattales]

Originally Posted by perchance

Do yourself a favor and put your mind at ease. Either do yourself or have done a compression and leak down test on the engine. A competent mechanic can perform these simple tests in an hour. If you have a mechanic do it be sure and be there with him/her and ask questions You will be surprised at what you learn.

Great suggestion. I just ordered a diesel compression gauge from Ebay. I'm also going to run the engine and crack open the fuel line into each injector one at a time. I'll check RPM drop on each cylinder and if there are big differences, I'll know which cylinder is the "weak sister."

[David M]

I disagree that oil analysis's do not tell you much. That is simply not true. Oil analysis tell you plenty of things. They tell you if there is coolant in the oil. They also measure trace elements in the oil which may be indicative of premature bearing failure or other failures.

Are oil analysis fool proof? No. Are they better than nothing or guessing what may be wrong?...absolutely!

An oil analysis is one of many tools that can be used to determine an engine problem or engine wear.

[Stillraining]

Originally Posted by David M

I disagree that oil analysis's do not tell you much. That is simply not true. Oil analysis tell you plenty of things. They tell you if there is coolant in the oil. They also measure trace elements in the oil which may be indicative of premature bearing failure or other failures.

Are oil analysis fool proof? No. Are they better than nothing or guessing what may be wrong?...absolutely!

An oil analysis is one of many tools that can be used to determine an engine problem or engine wear.

David....I don't see anywhere where anyone has said they do no good...

What has been said is quit the contrary...But ask any reputable oil analyst and he himself will tell you that one oil sample doesn't give you much information and is of little use.

You need to establish a benchmark for the engine with the first oil sample to gauge all other samples from for that particular engine..a rise in metals from that benchmark is you indicator.

I specifically stated that one sample could be painting an accurate picture.... but you will not know for sure until gauged by another.

If you have tons of metal floating around in the engine and it is a catastrophic event in the winds...you wont need an oil analyse to tell you that...you will see it or hear it...Oil analysis are a preventive maintenance measure not a once in 10year doctors check up and should not be advertized as such.

[svcattales]

I believe I'm getting closer to diagnosing the problem.

I ran the engine at 1600 RPM and loosened the nuts on fuel lines into the injectors one at a time. When #1 was opened, RPM dropped to 1368; #2 dropped RPM to 1500; and #3 dropped RPM to 1390. Hmmm... RPM drop on #2 was minimal compared to #1 and #3. While running I also measured exhaust gas temp in the hot part of the elbow and it was 125 degrees (F) hotter than other engine.

Today I checked the compression via the injector hole. The shop manual calls for 435psi when cranking with starter motor. #1 was 450psi, #2 was 90psi and #3 was 460psi. It looks like #2 is the "bad apple." I added a tablespoon of motor oil into the injector hole on # 2 and checked the compression again... it was still 90psi.

So what does it all mean? I'm thinking a burned valve or a blown head gasket. The head gasket might explain the high level of coolant metals in the oil test. What do you think? Time to remove the cylinder head?

[Stillraining]

Most likely a valve issue.... But before you yank the head off...Have you checked valve clearance.

Blown head gaskets cause multiple issues some of which are ...steam in the exhaust, rolling coolant in the header tank, foul smell out breather tube, hard starting, water in oil ( you have that I know)..., hydraulic lock ( you don't have that ) oil in the water

[svcattales]

Originally Posted by Stillraining

Most likely a valve issue.... But before you yank the head off...Have you checked valve clearance.

Blown head gaskets cause multiple issues some of which are ...steam in the exhaust, rolling coolant in the header tank, foul smell out breather tube, hard starting, water in oil ( you have that I know)..., hydraulic lock ( you don't have that ) oil in the water

Thanks again for the help. I did check the valve clearances and they were all about .050 thousands. My shop manual lists .020, but previous owner updated owners manual to .050 citing a Volvo service bulletin. I couldn't find the service bulletin, but too loose is better than too tight, right?

I'm hopeful that it is just a burned valve which is much easier to fix than new pistons/rings.