Synthetic oil in 420sel

Why shouldn't you be able to?

Why should it produce smoke?

DAS

For direct contact replace nospam with schmetterling

If you have smoking problem, you will lose oil whether it is synthetic or not. However, running synthetic on these engine is excellent...

High mileage engines do not take well to synthetic oil because of them being"slippery" it will get through worn internal parts more easily than conventional oil!Also if any of the seals on your car are leaking,then you will lose more oil on the ground than you would with conventional oil.If you are burning oil,this will get to be sort of expensive! I would suggest if you do put synthetic oil in,carry a few extra quarts in the trunk.Also,it is not recommended that you mix conventional oil with synthetic oil.If you do a lot of highway miles then synthetic oil will increase your fuel economy on the plus side due to less internal friction!

In fact it would be totally pointless; a waste of (the extra) money (spent on synthetic), no?

DAS

For direct contact replace nospam with schmetterling

I put synthetic in my old W126 at 200,000 miles when it never had any synthetic in its life... car ran extremely better with it. No leak or anything.

Eh. Sounds worse than it is. My car has 500+ K miles, leaks a bit and I use Mobil 1. Maybe I get 6 drops of oil in 24 hours instead of 4. Bif deal.

Nonsense. I've done it for years; what do you think semi-sythetic oil is?

And uh, Mobil says it's ok to do.

No, dino oils have some beneficial properties synthetic doesn't have; it helps. Plus you only need 10% synthetic to reap the benefits of the stuff.

And uh,Mobil sucks!And uh, the discussion is not about semi-synthetic oil!And uh,I work for Conoco Phillips here in Alaska at the North Slope Oil Fields! The engineers here would disagree with you about mixing conventional and synthetics until blue in the face.Believe me,I said the same thing as you! They lost me at polymeric dispersants and metallic detergents and wah,wah,wah............

My understanding is that by mixing conventional oil with synthetic you negate the benefits of the synthetic, which include, i.a., significantly slower degradation.

DAS

For direct contact replace nospam with schmetterling

Sorry,but I am a Castrol guy! I have always been pleased with their performance over any other brand! I even used it in my previous BMW's! Castrol synthetic oil is also tops!!!!!

Yes, I'd like to know the basis on which Mobil 1 is supposed to "suck". Well, maybe it sucks out the dirt from the engine...

It has been and is the recommended Merc synthetic. What's more it has a racing connections.

DAS

For direct contact replace nospam with schmetterling

Perhaps it was just my response to the condescending response that I received from the message I posted from Richard Sexton.I interpretted his response in this way."And uh" "big deal".Personally,I have never used Mobil 1, but have heard negative reviews by word of mouth! But Richard,I do love your choice of old Mercedes, for what it's worth!

I have a '79 240d w >200k miles.

I use synthetic.

I buy the wal mart brand at about $12 per five quarts.

no leaks.

Seems to do ok.

j.

You do negate one of the biggest advantages of running a pure synthetic which is the longer service life...