Hmmm....I'm not sure what the exact science is, but I'm sure I've opened the great ol' ACMOC oil debate again.
Here's what I do know. I started using Texaco Ursa oil in 1977 for my business because my father used it in his 'dozer business from way back when Series 3 Oil was introduced. I bought my oil from the same Texaco distributor that my dad used and was now managed by the son of the man that my dad had started with.
This Texaco distributor had a large office wall full of excellence awards from Texaco and he would often help me find the product that would best suit my need. He would would not hesitate to call the Texaco tech rep to find an answer if I asked for something unusual. 
When I started buying older Caterpillars he again recommended Ursa oils and continued to do so until Chevron bought Texaco, he then told me that the Delo 400 was the equivalent to Texaco Ursa and I should use it.
I have not had any problems, but I'm sure I'll see an avalanche of replies to this...
Craig
 

why i do not believe in the big A$$ dollar synthetic oils....
-2005 Silverado 4.8L gas engine, regular oil and filter changes....5000 mile intervals
-any brand of oil filter
-any brand of 5w-30 or 10w-30 conventional oil
-333,000+KMs (206,000miles) on the clock
- still does not burn oil
-have not ever added engine oil....if it ever reached "add", it was time for oil change
-your oil mileage may vary

seiscat wrote:

Hmmm....I'm not sure what the exact science is, but I'm sure I've opened the great ol' ACMOC oil debate again.
Here's what I do know. I started using Texaco Ursa oil in 1977 for my business because my father used it in his 'dozer business from way back when Series 3 Oil was introduced. I bought my oil from the same Texaco distributor that my dad used and was now managed by the son of the man that my dad had started with.
This Texaco distributor had a large office wall full of excellence awards from Texaco and he would often help me find the product that would best suit my need. He would would not hesitate to call the Texaco tech rep to find an answer if I asked for something unusual. 
When I started buying older Caterpillars he again recommended Ursa oils and continued to do so until Chevron bought Texaco, he then told me that the Delo 400 was the equivalent to Texaco Ursa and I should use it.
I have not had any problems, but I'm sure I'll see an avalanche of replies to this...
Craig
Thats good then if the rep recommended that oil, oil additives have changed over the years.

 

I have never been real concerned about the brand of oil as started farming in the late 70's with a RD 6 and then a RD7. The current oil is better thing has worked for me so far. But as Rome has pointed out since clean air changes that might not be so in the near future.
So far at TSC or chain auto parts stores the Delo and Rotella have 2 grades. One clearly marked for the engines with DEF and I think other criteria, I always get the other. The 9u D6 getting the run time here has a leak or 2 and burns some. But also pulls as good as any 9u I have been on, and 2 others here always seemed better than the rest. Then I happen to get some probably correct history but no way to check it completely today. The local go to guy had been the ranch mechanic where this tractor started it's carrier farming. He was indepent at that point but the ranch let him have all the shop space he needed.

So I stumble on the Delo 400 on sale about 2 years ago. Oil consumption has gone way down. Slip a gallon of Rotella in and right back up. I have heard of things like this but the first time I had it happen.

But this is a hydraulic oil tread, and I had new experience a few weeks ago. The disks, cultivator, and chisel plow are plumbed with cylinders that need more than 800 psi most old BeGe pumps make. No hydraulics of any kind on D6 when I got it. So I got 10 to 15 gpm vane pump, and a matching control valve, hose, and high pressure fittings from Surplus Center for about $500. Had a tank and the drive plate with u joint for the crankshaft. Since the the yellow bucket transmission and hydraulic oil is the cheap stuff and my pump is cheap one. That is what I have run.

I ran the disk 2 or 3 hours and hydraulics are slow, had a leak. So added a bucket did another 3 hours and disk is very slow to close to cross a creek. Ten mintes latter will not close at all. Start checking the next day not out of oil. Good time to work on leaks open hose no flow to pump. The screen in the tank was covered in a wax like substance and blocked all oil flow to pump. Upon fixing tank mounts and the leaks pump still works. Folded up the 30 foot cultivator that only has 2 1/2 inch rams. But all the old BeGe pumps then had screen let alone a filter on them like I put in the made it myself for cheap outfit.

So I have not idea how or where the wax came from. Could it have been from running different brands of yellow bucket, and there was reaction of additives? Are there any additives in yellow bucket oil? Or move up the ladder to more expensive oils. Sure glad this was on a $200 pump and $2000 dollar one like might be in Cat system on a D6 C.

Well I personally would not use engine oil In any hydraulic system I would use hydraulic oil. In really cold weather iso 22 or 32 in warm to hot weather iso 46 or 68 and if the machine has a lot of hours I would expect not to go below iso 46 as the hydraulic pump will have wear and you will lose performance with the lighter oils

Sorry had to.

 

I purchased D6D 4X7366 new in 1981. The Caterpillar recommended oil for the hydraulic system was 10W diesel engine oil. I ran the 10W diesel engine oil for about 8 years, then switched to 30W diesel engine oil. I operated that tractor until 2000 when I sold it to a friend, he ran it for another five years before he sold it. That D6D ran for 24 years with no repairs to the hydraulic system other than hoses(I lost track of that D6D when it sold again). I also ran Texaco Ursa engine oil in the hydraulic systems of a second D6D and a D6HLGP with no problems. 
I now run 30W Delo 400 in the hydraulic systems of the D7E and the D6B.
Craig

BTW, my Texaco distributor recommended Texaco Rando hydraulic oil for my D7E and that's what I used initially. Over the years due to hose failures(age related) etc. One day I needed oil for the hydraulics and I was out of Rando oil. I live 10 miles from town and rain was threatening my project, I had plenty of Texaco Ursa so that's what I used. I continued to use the Ursa oil and now the Delo 400. This oil is more expensive but I have never been disappointed.
Years ago my father told me "Never buy cheap oil, good oil is cheaper than parts." I still believe that to be true.
Craig
 

Twenty ++ years ago when I had a Chevron dealer I used a lot Delo 300, and I think they had a 200 that was oil for gas engines.