EXXON Oil

[Guest AWBE]

I bought some Exxon SAE 30W (Svc SL)to put in my 1955-322ci. The Shop Manual says I should use SAE 20W (Svc ML). I am going to change the oil and will use 6 qts. of this oil with 1 qt. of "Marvel Mystery Oil"---which I have been using for years. The engine has 76K miles on it and I am afraid to use HD oil. This has been the only plain 30W I could find. 20W is not heavy enough in the summertime.

Am I going to cause any problems????

[NTX5467]

The old "ML", and later "MS" oil designations can't be found anymore, the new ones have replaced them, with the newer designations being far superior oils in many respects.

The 20W vs. 30W issue probably will not make much difference. In some cases, factory recommended oil viscosity can also relate to ambient temperature ranges. In those earlier times, multi-weight oils basically did not exist for anything other than highly specialized applications. When using 30 vs 20, though, you might be a little easier when you first start it, letting the oil pressure fully build before putting any rpm into the motor past normal idle speeds--probably for the first minute of running (which might not be a bad idea anyway, even with the 20W oil).

If the "20W" designation is important, you might also consider one of the many 5W-20 oils that Ford and Honda now spec for their motors, but I would suspect somehting in the 10W-30 range would be generally better. Of, if the temp range is above freezing, using 30 yearround could work too (usually a more recent viscosity recommendation for "straight weight" oils in modern style motors).

If you're concerned about the detergency levels, you might change the filter after about 1000 miles or so, just to see if there's any extra accumulation of "things" in the element from the higher detergency action. I suspect that unless you add some specific cleaning additives, there (most probably) should not be any problems--just my gut suspicion. If the engine is totally gunked up from prior times, then using a cleaning additive and then following that with a fresh oil/filter change might be appropriate. Your judgment call . . .

Just some thoughts,

NTX5467

[Guest AWBE]

Many thanks-----I had always used Havoline 30W for the last 35 years---but can't find any now. Thus the question about Exxon Svc SL. '55 Shop Manual says I should use 20W Svc ML. I prefer the 30W because of how hot it gets around here and I never run it when the temperature is below 35 degrees. I have also used Marvel Mystery Oil in the crankcase and also in the gas. (Comes from my experience with old Fords in the late 40's and early 50's.) Get a big kick out of watching the white smoke ring that will come from the exhaust every 30 seconds or so while it idles.

[NTX5467]

Most of the consumer engine oil market is heavily biased toward multiweight oils now. You might check the Havoline website to see if they still have the desired 30W oil. If they do, you might get your local distributor to order you a case or two (on their next stock order from their factory warehouse).

You might also find a "fleet" oil that they have that is 30W viscosity. It might not have all of the more recent "approvals", hence might be closer to what the earlier oil spec was in that respect. Might be diesel-rated too. Kind of like the old MS/DG rating, but with more recent alpha-numeric codes for upgraded ratings/approvals.

Enjoy!

NTX5467