How useful is Govplanet oil/ fluid analysis info to us as buyers?

[greenjeepster]

I noticed that GP is doing oil analysis on some of the trucks they are selling, but not on all of them. I understand when they note that fluids were drained and they could not start, but on the rigs that they did test run why would they not report analysis results on all of them? After comparing results on the vehicles they are checking it looks like they are reporting analysis when there appears to be excessive wear. I haven't seen any analysis with great results.

Most of the information tells us nothing but how recently the fluids were last changed, but I pay special attention to glycol levels and fuel levels. Fuel is to be expected in small quantities, but glycol (antifreeze) in the oil is a bad sign in any amount.

As far as compounds go; any engine oil that has been run for a while is going to have some compounds in it, but excessively high numbers can be worrisome. One truck I had on my watch list on Feb 25th had copper in the trans fluid at almost 600 PPM and iron at almost 200 ppm... not a good sign that that transmission will be around very long given that the military is really good at keeping fluids changed.

 

[brasco]

I'm with you. I think oil analysis results are OK to determine major issues like glycol in the oil but trying to determine excessive wear and other issues might be a little tough without a trend established with previous results. Unless you know how many miles are on the oil and other factors, like how long the truck was sitting unused, I would not put too much stock into them.

For example, the engine might have major wear issues but the oil may only have a few hours on it and would not show a lot of bad stuff in it. On the other hand, a good engine may have a lot of hours on the oil and have higher contaminants. I'm sure sitting for years without running doesn't help either.

I use oil analysis for my Cessna 182 and discovered a ring issue after establishing a trend. Without a long term trend established, I'm not sure we would have discovered it. Blackstone labs even gave me a phone call to tell me about it after running the oil sample and saw a spike in the results. I highly recommend them.

It would be helpful to know what the "normal" levels are for iron, copper, etc. I know that Blackstone has this information for aircraft engines; they probably have it for other engines too. If someone here has done a Blackstone lab report for their M923A2 etc, the data is probably on the report. Maybe they can share it here?