Oil Analysis Oddities

[johnd]

Here's an interesting Mobil 1 story for you. See analysis attached. on the 11/04/00 oil change, the car got it's first Mobil 1. Lead and iron were high. The guy at Blackstone said he had seen this before on changes to Mobil 1 but that it would still be a good idea to sample it later. Note that the sample mileage is 5000 mi. I changed out the K&N for a paper air filter and silicon went down. On the next samples at 2940 and 1800 mi., respectively (the oil was changed each time), lead levels were 16 and finally 7, which is normal. I should mention that some of the high levels of metals on the bottom of the sheet are oil additives, ignore these readings. Next oil sample is 31k mi. later with 4944 on the sample and, guess what, lead level is 46. Based on the insolubles, fuel dilution, etc., this oil isn't even beginning be old-so why is the lead level so high? Based on the prior results, I'll be willing to bet that the lead levels at 3K mi and 2K mi on changed oil will be just like last time. Anybody got any ideas? This car is a daily driver, never used in competition and has absolutely no aftermarket additives of any kind.

 

[TR3-2001SE]

Based on the viscosity being high, the insolubles being close to the normal limit, your engine is beating up this oil good. Why could be many things. PCV valve would be my first check. What car/engine might help us figure it out.

 

[fuel tanker man]

Where's the report?

 

[johnd]

Sorry about that, I posted the report scan that cut off the engine type. This is a 1997 Camaro Z28, LT1 engine. The viscosity was within their normal limits-why did you say high? PCV valve has never been changed but it appears functional-what bearing would this have on high lead levels? The part I can't figure out is that, using Mobil 1 at least, lead levels climb over the 5K service time on both changes. It does not appear to be silicon contamination (aka grit in the oil)so what is the cause? I'm stumped. THe only things I can think of is:1. an incompatibility between Mobil 1 and the bearing material which seems impossible, considering the recommendation of the manufacturer to use it, or:2. Abrasion from particles too small for the filter to catch which seems unlikely-esp. with the insolubles level shown.

 

[DJ]

M1 5w-30? Everyone thinks it is the ulimate oil for the LT1 but analysis shows higher wear than with some slightly thicker oils. Do a search using LT1 and see what has been discussed and found to work well. Remember GMs goals in specing an oil are not all out longevity, marketting and milage(CAFE) will rank above because almost any SL dino juice should take this motor beyond 200K.

 

[TR3-2001SE]

M1 5w-30 starts off with a viscosity of around 60.0. It is very unusual for this oil to thin or thicken. After 6200 miles in my Mazda Miata it is still 60.0. This is a clue for us. The insolubles on my Miata after this milage is .3. This is consistant over 3 changes of around 6000 miles. This is also a clue for us. Your engine is getting dirty quicker or the oil filter is not working very well. What are your insolubles and viscosity over the other UOA's? My understanding of your engine is it does like a heavier weight oil. 5w-40 Mobil 1 might improve things. I would still replace the PCV valve with a new one. We have seen elevated lead caused by PCV valves. You will get more responses to your questions if you post your Used Oil Analysis in the proper fourm.