There is a tremendous amount of bloviating here on the properties of one oil vs another. Many of the discussions are really gear head oriented and way beyond the understanding of normal human beings. In fact, most of the arguments are of the "who is better: batman, or superman", etc type discussions and are filled with the dire consequences of using the "wrong" oil. Personally, I use the 0W-40 oil that the dealer puts in as I get if free and at 42K have had no oil related problems.

In any event, below is a link from the NY Times which can both be understood by all and serves as a caution for those who believe that the Japanese not only produce cars worthy of the Gods, but also treat their customers like royalty.


http://www.nytimes.com/2007/02/04/autom ... LUDGE.html

The real problem with sludging was the start of 97 model year required the reduction of oil vapors from the crank case by the oil return gallerys(sp) and that some mfg's failed to realized that the 10w-30 oil they used was too thick to flow proper in most engines. Once mfg found the problem and then got dealers to comply to the use of 0w-40, 5w-20, 5w-30 were necessary to prevent sludging in all new gas (not diesel) engines. I use Mobil 1 0W-40 and 6500 mile oil change and the oil is clean and not sign of sludge starting in valve cover area or on the dipstick. In a gasser if you see the brown to black crap on the lower section of the dipstick you have problems.

The 0W-40 Mobil 1 is an excellent oil for use in the CRD if it were running ULSD fuel only so as to have less soot in the oil. The 0w-40 however does not carry the soot well enough for any real long OC period, my guess 5000 mile would stretch the limit, but the Mobil 1 5W-40 T&SUV or Delvac 1 oil will easly handle the soot load to 12,500 mile mark in everyday driving as most here do. I am now using only ULSD (3rd tank) and am going to do a oil and filter change at 10k miles also will send oil sample sent off to test prior to changing to see what shape the oil is in, then change to the 0W-40 and do a check again at about the same point mileage wise. One reason i want to get back to 0W-40 is it is cheaper and easier to find the the 5W-40 T&SUV.

A D tech at my dealership says he only uses Shell in his rig. He claims the mix holds the soot in suspension well. It is 5w40. I was told there were no differences in 10w vs 5w after warm up. It all goes to the 30 or 40 w after that. The reason manufacturors went to 0 and 5w was to try to get better fuel economy, and to get the extra oil up to the upper engine a little quicker.

I will have to see your oil lab results. Hard for me to break old habits. Might be a waste of money for me, or it could be peace of mind. That is worth something in my life.

Peace of mind is worth more then any oil lab result in most peoples mind. I have no problem with that at all and to me peace of mind is the ocassional oil sample being tested.

I haven't done anything but 10,000 mile oil changes in almost 30 years now, (the exceptions were during early warranty period) when I started using synthetic oil in summer of 1977 I went to 5,000 mile changes and then about '84 I went to 10,000 mile oil channges in my cars (gassers) but stayed at 5,000 in my motor cycles (same brand & wt, M1 5W-20) and I have driven most cars and trucks well past 120,000 miles and either traded or sold them. I sold one, a 87 Cherokee, to a neighbor and they have continued the 10,000 mile oil changes and the Jeep has 300,000 miles on it and is still going strong.

All those years friends would tell me I was crazy and would ruin my car, just like so many the last 6 or 7 years have been telling me I will blow out my tires or at the very least wear them out early because I run 40 psi in a tire rated for 44 psi. I am still here with excellent tire wear and never a tire failure except from foreign objects or vandalism and cars that last so long I get tired of looking at them or their body rusted out as several have over the years. I have never had a engine filure since I started using Mobil 1 synthetic oil in 1977, so I guess that is what I find most of my peace of mind in these days.

Personally, I will not go beyond a 6,250 mile oil change interval with my CRD. My oil analysis' that I have performed over the last 36k is what made up my mind. It's not so much the oil not being able to stand up to longer intervals; it's really the sub-par OEM air intake system that's my limiting factor.

What problem have you had? I had a misshaped lid that would not seal properly that was replaced, then I replaced the lower section to change to gasser style intake over the top for radiator brace.

My one test was normal soot load for the M1 5W-40 T&SUV but had a hi Si and the suggestion was to check for air leaks in intake system and I discovered the problem, then the lid actually broke when I was trying to get it to fit propper. I plan on pulling a sample this weekend and having it tested again, the oil will be at 7,xxx miles and the week it takes to get the results back will be quick enough if I have reached the limit.

I would be interested in seeing the results of your upcoming analysis. My problems have also been relatively high Si levels. Aluminum is also "kind of" high but all other wear metals are very low. I have also had normal soot load readings.

Please let me know (by PM if you like) the results of your upcoming test.

No problem, will do. I wanted to do it yesterday while it was in the 50's out and garage was about 70, but the wife was off and gone with the Jeep. I only see the thing on weekends and then I have to have an appointment.

It was about 52 here yesterday, but mid 20's today. Mine was done by removal from firewall. The CRD was in for new ERG and since they took the filter and mount off to get at EGR, I just threw on a filter. I asked the tech if he had changed any of the CRD filters and he said he had and that he just removed the whole unit the one time and second time tried it without head removal and thought it was faster and easier that way. I have thought it would be esier that way myself.