Newer Oils in Older Engines
 

When I work on Cecilia I think, "What is keeping me from taking this from here to texas?"
Thats how I figure out the next thing to tackle.

I'll be working on fixing her main leaks (and her door, but that's another story) for most of the summer as soon as I'm able to get on the ground again. I'm replacing her transmission, transfer case, and differential oils with Redline brand gear oils because Jay Leno recommended them and I got the part numbers from the company. They're pretty nice.

The engine oils though, I'm thinking of going with Rotella Diesel oil. It has zinc in it and I can get it in the recommended w20 that the manual calls for.

Has anyone else used Rotella in their engines? If not, what are you using? Additives?

Re: Newer Oils in Older Engines
 

I'm using Rotella 15w-40 in my 478M as the breakin oil and I think I'll continue using this oil for good. Pete Chronis Northern Cal. 68 GMC KM-2500 478M V6

Re: Newer Oils in Older Engines
 

I just use a zinc additive with standard oil. There is a cam break-in additive (cant remember the name right now) that is very rich in zinc and I just add a small bottle every oil change. I don't run diesel oil in my gas engines because it is usually more expensive, usually comes in gallons only, and viscosities are usually 40w or above.

Re: Newer Oils in Older Engines
 

Hello again FetchMeAPepsi!

In regards as to what oil to use, I have to recommend Synthetic oil, (it certainly won't hurt your engine) and I am currently using Mobil 1 15w50 in my 1999 Pontiac Bonneville (3.8 V-6, never rebuilt) with 280,575 miles on it. I go five to six thousand miles between oil and filter changes, and only use about a half quart of oil. Synthetic is a bit more expensive, but the extended mileage between changes more than makes up for the extra cost, and there is an added benefit (at least in my neck of the woods) of easier starting in winter months since synthetic oils don't thicken up like regular engine oils do. I have been using synthetic oil for several years now, and I will not go back to using regular engine oil since I feel synthetic is far superior to regular oil. Of course, these are just my thoughts, and others may disagree with me as to the benefits of using synthetic oil. I am a very picky individual when it comes to engine care, and if I don't believe in using it in my own engine, I'm certainly not going to recommend it to someone else.

Re: Newer Oils in Older Engines
 

Synthetic oil is just fine specially in newer engines with roller cams, older engines such as the GMC V6 with flat tappet cams will need zinc additive added to the oil or the results may end up with a flat cam.

Re: Newer Oils in Older Engines
 

Not to start an argument here, but my 99 Bonneville is not equipped with a roller cam, and I have had no problems using synthetic oil, and I do not believe the camshaft in my engine is any harder, or had any different type of heat treatment than a camshaft from a 1960's era engine. In fact, the last 75,000 miles my car has been driven has been with synthetic oil. In fact If I had an engine of that vintage (1960 and on), I would not be afraid to use synthetic oil in it, even without the zinc additive, since synthetic oils have better lubricating qualities than regular engine oils. Case in point being, synthetic oils are not recommended for use until new or rebuilt engines are thoroughly broken in, since new piston rings do not break in properly due to the the excellent lubricating qualities of synthetic oils. Again, just my opinion, and not meant to offend or upset anyone in this forum.

Re: Newer Oils in Older Engines
 

If you do some research you will find out that roller lifters were used on the 3.8 V6engines from 1986 on up. I've experieced a flat cam in my Jeep at around 3000 miles after installation, only used a zinc oil during initial break in. That point on I have used oil with zinc or poured in the additive, there's no need to take chances when so simple just to spend a few extra dollars for the additive or an oil that has it.

Re: Newer Oils in Older Engines
 

Greetings bigblockv6!

I did the research you suggested, and indeed, my 99 Bonneville (3.8 V-6) does have a roller cam as you said. I also visited the official Mobil 1 Website, and came up with some interesting information regarding Mobil 1 Synthetic Oil and flat tappet camshafts.

Quote from the website:
Question:

"Does Mobil 1 contain the Additive for Flat Tappet Cams?"

Mobil 1's Answer:

For older, flat tappet engines where wear may be more of a concern, we offer a number of synthetic oils which are higher in phosphorous than API SN/ILSAC GF-5 oils. These include Mobil 1 15W-50 (1,200 ppm), Mobil 1 0W-40 (1,000 ppm), and High Mileage 5W-30, 10W-30 and 10W-40 (900 ppm). For all newer engines and flat tappet engines in normal service, API SN/ISLAC GF-5 oils are preferred for better fuel economy and for the protection of catalytic systems with lower phosphorous (800ppm)."

This is a direct verbatim quote from Mobil 1's website which was updated in April of 2012.

My interpretation of this is that there is no reason not to use (or fear using) Mobil 1 15W-50 Synthetic Oil in a flat tappet engine where cam wear may be a concern. As I stated previously, I personally would have no reservations using Mobil 1 15W-50 Synthetic Oil in any engine that I would personally own, whether it would be equipped with a flat tappet cam, or a roller cam. Thanks for urging me to do a little research. I got a little education on both the GM 3.8 V-6, and the subject of Synthetic Oil vs ordinary engine oil. I have bookmarked Mobil 1's website for future reference since it addresses many more engine and lubrication issues than just those of flat tappet camshaft engines.

Re: Newer Oils in Older Engines
 

Wow those are crappy numbers I run AMSOIL high zinc formulas. I think they are like 1500-2500 for numbers actually maybe more so.

Mike

Re: Newer Oils in Older Engines
 

Mike, does it say the numbers on the bottle? I'll be picking up my fluids this weekend and I'd like to compare.