6V92 Oil Analysis

[Doug1968]

Fellows,

A couple of years ago I purchased a 1981 MCI 9 Bus that had been purchased new and converted by Pawnee Coach Works in Pawnee, Ok.

This bus had been well taken care of and I bought it with 164,000 miles. I had an oil sample taken and the analysis was clean.

Since that time I have put just over 5,000 mile on the bus and at the last oil change I had a sample sent in for analysis. This analysis cam back showing high Potassium (169ppm) and Sodium (137ppm).

In discussing this with other bus nuts there appear to be several possible areas that could be causing the coolant to leak into the oil. Things brought up are: water pump seeping, injector seal leaking, head seals, compressor head gasket leaking and possibly the oil cooler.

The oil on the dip stick is very clean with no sign of water. I have checked the vent hose coming out of the valve cover and there is no sign of water or milky residue.

The engine starts and run great and on my last 2,800 mile trip I added two quarts of oil.

I did add about a gallon of coolant last summer when I lost some while removing the Webasto Heater for service. Other than that I have not seen the water level change.

I talked to Rick at Hillsboro Diesel and he told me that 169 ppm is miniscule and a leak of that size would be difficult to find? He also noted that if the engine sits for long in cold weather that coolant can leak past the seals.

He recommended changing the antifreeze/coolant to a non glycol type in case the leak increases I wouldn't have the glycol eating at the bearings?

Many I talk to recommend using the bus and keeping an eye on the oil level and watching for additional water. Maybe after running another 1000-1500 miles pulling another oil sample for analysis.

I'm sure there are many bus owners that haven't had the oil analysis completed and they may have a similar situation and don't even know it?

I would like to get some feedback from you fellows to see if any of you have had a similar situation and if so what did you do? I would hate to ruin this engine.

Thanks,

Doug

[luvrbus]

Before you panic pull another sample and send it to a different lab for analysis,did the same lab do the analysis on the 1st sample ? and where did you pull the sample from.I don't see any mention of Glycol it will show up if the engine is leaking coolant into the engine,a Fourier test can tell if it's a coolant leak or not.You didn't add any additives like Lucas to your oil did you ?    

[Doug1968]

Clifford,

Two tests at two different labs, similar results.

I have not used any additives. Both tests noted that a high Potassium and Sodium are signs of antifreeze. What are your thoughts about either the water pump or the compressor having coolant leakage that might be causing the oil sample readings?

I pulled the oil sample by running the tube through the fill tube until it hit the bottom of the pan and then raising it back up off of the pan about an inch or two.

I was hoping that maybe someone on the board might have either had or knew someone with an oil sample analysis that tested high for Potassium and/or Sodium?

I wonder what percentage of the bus owners take oil samples and have the testing completed?

On another note, are you familiar with R&L Diesel in Stockton, California? They advertise that they are an authorized Detroit rebuilder. It might be that somewhere down the road I will replace this engine with a rebuilt and I want to start looking for sources?

I got rid of a really good 8V92 in the 102a3 I sold? I never guessed I would be having issues like this on a 170k mile engine. Hmmmmmmmm.........

Doug

[Iceni John]

A while ago I had my oil tested, and it came back with slightly high sodium.   A subsequent test showed sodium at a reduced level.   The reason (I think) for the elevated sodium level was because my bus had some car-grade straight 40-weight oil in it when I bought it, and apparently car oils have a different additive package in them than "heavy-duty" oils for diesels, so the lab assumed the car oil was the culprit.   Did your lab specifically detect glycol in the oil, or just sodium and potassium?

Talking about testing, I now have T5X oil in the engine, but I've been topping it up with Delo 100, and I just bought a gallon on Rotella T  -  they're all CF-2 rated straight 40-weight, but will the testing lab get indeterminate results from the mix of different oils?

John

[lostagain]

For years, I had the oil tested for the 6V92, and there was always one thing or the other that came back marginal, and worried me. I would talk about it with knowledgeable  mechanics, and they always said don't worry, it is normal. I have quit doing oil analysis, makes life easier. I change oil regularly, using the correct CF2 40W, and I would notice obvious things like antifreeze or fuel in the oil. I don't worry about it otherwise, just drive it. I have been running all kinds of diesels and gas engines the last 40 years without oil analysis, and without too much trouble. When something breaks, you fix it, and carry on. I can see how oil analysis would be helpful for a large fleet using the same engines, but the benefits for a single engine seem sketchy to me.

JC

[opus]

I have mine done every other change.  Just checking for anything way out of whack.

[VegasFlyer]

I think you will find if you drive it a bit, do another oil change, drive it some more, and do an analysis, things will be more normal.

I had a truck with a Silver 92 in it and it would show odd results when it sat for a while.


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[Scott & Heather]

My
Oil analysis just came back:
1. Lots of abuse heaped upon your lowly 6v92 this past year
2. Dude, change your oil more often.
3. Man, did you seriously mix rotella and delvac?
4. Stop running me hard right after starting up in single digit temps.


So yeah, I definitely am going to need a rebuild


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