What motor oil do you use for a 1970 IIA?

[gudjeon]

I don't bother with UOA's as one analysis costs as much as replacing with another batch of oil. I am just going by what the oil gauge does with a lighter weight of oil in warmer temps. Seems an overkill approach to a 1950's design engine. I like using decent stuff like the next guy, but I have other things to worry about. Now if I drove and engine that would cost me 30K to replace, that would be another story...

[jac04]

I don't bother with UOA's ...

Sorry, based on you statements I just figured that you had UOAs showing some specific 5W-xx or 10W-xx oils that showed an unacceptable viscosity breakdown after a relatively short period of time.

I understand that everyone has their own views on engine oil. Unfortunately, people tend to read what others state and take it as fact. Also, people tend to believe that "thicker is better" for engine oil. It may seem like a good idea, but an oil that provides a viscosity higher than the design viscosity at operating temperature is providing absolutely no benefit.

[gudjeon]

I just get nervous when an oil works out great at first, but thins out when it get hot, especially when hotter weather hits. An oil that can maintain its viscosity on the gauge is what I go by. Seeing the pressure dwindle when at idling at a light is not what I look for. Also, I have settled on changing once a year using a 0w50 or 5w40 for my all weather, all condition driving habits. I used to be a summer oil/winter oil guy.

[NickDawson]

Im in Richmond just south of you, I've been running straight 50w (which is surprisingly listed as standard in the green bible for my 2.5L).

[bmohan55]

If you run rich (I have a rochester carb) and drive it a lot I found it's best to change it more than once a year because the gas may "leak down" and dilute the oil.

[luckyjoe]

jac04,

For my 109/2.25p, I just do not see any advantage to 5Wxx or 10Wxx oils. This is not to say they are a bad choice - they just don't put anything on the table so-to-speak. The 25W50 covers my application range quite well (presumably with less VII's), and is easily hand-cranked to build oil pressure prior to frigid starts.

I run Mobil Delvac1 5W40 in my 2003 VW Tdi, which is a modern (Group-3 base-stock) full synthetic, but this is simply not necessary for the 2.25p's working conditions. The Tdi has run Delvac1 since the initial break-in was complete. At 161k miles it has not lost a single psi of compression and returns 52mpg (highway). This is a tough application and UOA (I have not bothered with this since ~2005) has shown the 5W40 still has plenty of life at 10k change intervals.

On a whole I change the 109's fluid way more than needed (motor/diff's/trans/t-case/OD) but relax at the thought I can jump-in and go (long-haul, wheeling, daily-driver...) whenever I want.

Tom P.

[jac04]

The 25W50 covers my application range quite well...

What in your "application range" requires the use of a 25W-50 oil? Just curious.

[73series88]

10w 30 from wallmart all i ever use in my rover
aaron

[I Leak Oil]

10w 30 from wallmart all i ever use in my rover
aaron

And it hasn't grenaded yet?!

3 pages of debate on motor oil...wow.....

[jac04]

3 pages of debate on motor oil...wow.....

There are entire forums dedicated to debate on engine oil.