I just got back my first Blackstone Labs used oil analysis report, and in almost all dimensions it was excellent - all wear metals below average, and no fuel or antifreeze contamination. The only wear metal that was slightly higher than average was aluminum, which came in at 9ppm, versus 4ppm average.

As you may know, the engine in my '03 Disco II was very noisy when dead cold at startup, and then quieted considerably when warm. I replaced the rod bearings which made it even quieter across all temps, but there was still noise when dead cold.

I am now thinking that it could be piston slap, given the slightly elevated aluminum in the oil sample and the fact that it quiets down when warm. However, I also wonder if it's possible that the bearings I took out had aluminum in their construction? The oil sample was from when the engine had the old bearings in it.

Thanks!

 

Bearings not aluminum. You could also have wear on the rockers.

 

That makes sense - would that potentially come across as engine noise while cold?

In addition, it definitely gets louder once the transmission is in gear and more load is put on the engine. In fact, simply going from Park to Drive increases the noise when cold.

 

What do they charge you for the oil analysis? We do this at scheduled intervals on aircraft turbine engines. The items being aluminum are the block of course, the front cover, pistons, and rocker arms. Are they analyzing the filter also? I'd be curious what is being captured in the filter.

 

Hi 0304,

It is $25 for the analysis. There is no filter analysis - this is just the oil captured when draining for an oil change. They compare your sample versus the universal averages for other engines of the same type to provide their benchmarks. So, in this case, my sample is compared against other Disco IIs.

 

Pull the rocker arms from the rockers shaft and you will see the first of a few thing you will need to replace, very common.

 

I've got a set of rover main bearings on my desk, and they certainly are not aluminum, but for some reason I'm thinking the set of rod bearings that I had to return were made from aluminum. They were for the older style block though, that's why I sent them back.

 

This! Rocker arms wear out, and they are aluminum.

 

I thought I remembered this from the RAVE:


Number and material .................................................. ...... 5, Lead-indium

Indium is an element, used for lubricated bearing surfaces in aircraft in the 40's; but today most of you carry it around as an ingredient of your touch screens. Enough wear, and you are into the copper.