changing oil to synthetic

[hippiehulahooper]

I have been reading some of the threads on synthetic oil choices. my question is what about changing a 1.6 over to synthetic. would it be a bad thing? or a definite go?

[dieselsnowmobile]

I change to Syn without a problem. Went from Rotella 15w40 to Rotella Syn 5w40. Leaks oil about the sam as it did before. Some say Syn oil makes an engine leak, but not it my case.

[hippiehulahooper]

Some say Syn oil makes an engine leak

that's what I heard from a big rig mechanic.
the only leak I have currently is on the valve cover behind #1 cylinder. (I thought a one piece rubber might help with that and checking the valve cover more thoroughly should help. )
and I was wondering what leaks would happen from the change and why? I assume the synthetic is thinner.

[A1-2-A3]

So crankcase pressure goes up with synthetic oil? Or are you talking about blowby on the snot hose?(big rigger) I can not see it making any differance for oil leaks myself.

[82vdub]

I think it's a crapshoot whether your gaskets will leak or not. I've heard peopel switching and no problems, and I've heard people switch then go back because of the oil slick the car leaves.

[Wolfsbur]

Some say Syn oil makes an engine leak

I assume the synthetic is thinner.

A syn at 10 30 should have the same thickness (viscosity) as a dino at 10 30, both at the same temps--right? Otherwise, why have viscosity numbers.

From years ago (late 70ies) when Syns became more available, the leaks issue was blamed on seals not designed for the different chemistry of the syn, thus they would 'shrink' and allow oil to go by. And, the detergent qualities of the syn is superior to that of the dino oil, cleaning away accumlated muck that may have been helping an otherwise bad seal hold back the oil.

I'm a big believer in full syn and extended drain intervals--just about the first thing I do to a car after getting it (no matter the miles--and assuming it isn't burning oil at a rate worse than 1 quart per 1K miles) is switch over to Syn.

[hagar]

In Kentucky ? ---- from hagar it is a definite NO ---extended interval in a VW diesel that old ? --NEVER -----------send me by mail a Blotter test and I shall tell you WHY .

Yes I love synthetic lubes I use a lot.

hagar.