Which Oil is ok to Run?

[torqueflight]

My first oil change is coming up since I have owned the car. It has 173k on the clock. I'm not sure what to run. I don't really remember what the previous owner said, other than he ran 10-30 in it. But the guy was a total liar anyways.

I was wondering if it would be an F'd up move to run semi-synthetic? I didn't want to run full synthetic because if its never had it in there before I don't want to mess the seals up.

Any help would be great, thanks,
Matt

[jlevie]

For SoCal, 20w50. You can run synthetic, but you may see more seepage from seals and gaskets. And with the shorter change intervals of these engines synth will be more expensive.

[StereoInstaller1]

Wal Mart "High Mileage" has an excellent zinc level and is cheap.

Mann or BMW filters only though...no american brands, certainly not Fram.

[StereoInstaller1]

I should point out the Wally world oil is excellent quality....I change my oil quite often (at 275,000 on the motor) and the WalMart stuff seems more viscous than Castrol, which is what I always ran before the High Mileage came out.

Old motors need zinc, WalMart has about the highest %.

[Goggles Pizano]

Motor oil for diesel engines has a lot of "zinc" (ZDDP) levels as long as you have no cat.

[nando]

I want to try Rotella, but I don't know a lot about it. My other choice would be Castrol GTX 20w-50 or what I've been using for a while, M1 15w-50

[MR 325]

Don't waste your money on fancy oil, or synthetic.

20w50 Shell or Chevron is just fine.

Matt

[SpecM]

I like Castrol GTX 20w-50, but this last oil change I tried Rotella 15w-40, it has a VERY high zinc content, not sure how it compares to Wally-oil tho...

[DaveSmed]

SuperTech (Walmart's store brand) is rebranded Quaker State.

[DCColegrove]

20W/50 is actually necessary in the old m20s (15w50 is probably close enough though)... and high zinc content is a good thing in these old critters but hard to find in oil anymore.

[Bimmerista]

SuperTech (Walmart's store brand) is rebranded Quaker State.

Wow...had no idea.

I just bought myself Castrol GTX 10w-40 about 20 minutes ago from Wally World. Figured 20w-50 is a bit thick for winter.

[moatilliatta]

Quacker stat makes killer sludge though right?

[ForcedFirebird]

Here's a list of content of oil from your major MFG's...

http://micapeak.com/info/oiled.html

I agree, stay away from Fram. Even on my American cars, Fram sux. Usually have to overtighten them to get them to seat without leaking.

[Knockenwelle]

I run Rotella T here in winter (min air temp ~20 deg.) in everything I drive with a non-roller cam. As slow as my M20 builds pressure in the morning, I wouldn't want to use a 20W- anything when it's cold. Plus, with the stock oil cooler, you really don't need the 50 weight unless you're tracking the car; it's just to keep the motor quiet. I also add a bottle of Comp break-in additive to everything non-roller at every oil change just for the insurance. $8 per bottle of essentially pure ZDDP is worth it, especially for expensive camshafts.

Check this out:

http://www.lnengineering.com/oil.html

[DCColegrove]

It is true that 20w is rather thick for very cold weather however...

The design of the cam rockers and rocker shafts in the m20 require this thick shit for hydrodynamic lubrication...

But then again with the low zinc content (which bonds to the metal and acts as a sacrificial coating) running dry on cold start ups ain't so good for the valve train either...

So I guess it's six of one and half a dozen of the other...