Acantor

So I'm restoring my 944 and I just finished the rod bearings and oil pan gasket. I am going to fill it up and run it but I don't know what oil to run. Autozone said 15W-40 or 15W-50, but that seems awfully thick at startup and that's the oil I use on my 7.3 Powerstroke diesel. I did not think that that thick of an oil at start was good so I went to oriely and they recommended 0W-40. I looked it up and I'm seeing all kinds of weights. I am not going to be racing the car, but I do have a bit of a lead foot so with that in mind what oil weight should I use. Conventional or synthetic? Did these engines have different tolerances back then?

V2Rocket

15w50 or 20w50 are correct as long as the ambient temperature is above freezing.
these are very old engines (dating to early 1970s design) and have very wide bearing tolerances - need thick oil.

Acantor

I live in Colorado and half the year is pretty much below freezing. But then again I probably will not be driving it when it is that cold. Thanks for the input!

Micah

Manual.

Acantor

Thanks for this, I'm guessing this is synthetic blend? Or is it full synthetic? Since it is so old

Micah

It doesn't matter.

BeerBurner

I use Mobil 1 15w50 year-round with annual oil changes (5-6k miles). While I'm not sure if it's the ideal thing, the car has 196k miles on it and is going strong so I don't see the need to change anything.

BB.

Acantor

Ok that's probably what I'll go with then thank you

jeyjey

If you're going to drive it in winter I'd go with 10w50. (But I grew up in Glenwood Springs, which might be a bit colder than Colorado Springs?)

Acantor

I probably will not drive it below freezing anyway. Planning on splitting the time with my truck so🤷‍♂️

goblues38

20w50 for me in STL. It gets quite hot in the summer, and the S2 runs hot. I purposely put summer tires on my cabriolet to keep me from driving it when it is cold......so no need at all to switch to a 15w50

Acantor

Thanks to you all for clearing things up, I went and picked up some 15w-50 today!

944StaceyQ

Dino Castrol GTX 20w-50. Great price at
W-mart and these older German engines love it. 170k+ miles and running great.

Not_Sure

read this:

https://540ratblog.wordpress.com/

heres an excerpt of the current first oil in the ranking,(since it takes half a day to get through the "about" section)

"the “WEAR PROTECTION RANKING LIST” itself, begins here:

1. 5W30 Quaker State “Full Synthetic” (abbreviated QSFS), dexos 1 Gen 2, ILSAC GF-6A, API SP = 152,674 psi
And that psi value sets a WHOPPING NEW ALL-TIME RECORD for motor oils that I have put through my Engineering Torture Test on motor oil. It was tested in Spring 2021.
This new 5W30 Quaker State “Full Synthetic” motor oil replaces the previous 5W30 Quaker State “Ultimate Durability” (abbreviated QSUD) synthetic.
zinc = TBD
phos = TBD
moly = TBD
The psi value of this new oil, which came from testing it at the normal operating test temperature of 230*F, put it in the SPECTACULAR Wear Protection Category. However, I went on to also test this oil at the much higher temperature of 275*F. At that elevated temperature, most hotter and thinner oils typically experience a drop in Wear Protection Capability. But, even at that elevated temperature, this oil produced an extremely impressive 148,133 psi, which was only a small 3% drop in capability. And that value put this much hotter and thinner oil in the AMAZING Wear Protection Category.

I also tested this oil to find out its onset of thermal breakdown, which was 290*F.

This new oil was purchased at Walmart. And its truly amazing performance is further proof that Walmart is selling legitimate motor oil, even though their prices are extremely low compared to typical Auto Parts Stores.

Many of us who have been devoted users of the previous Quaker State “Ultimate Durability” motor oil, were concerned that Quaker State’s Corporate bean counters might get their hands on this new Quaker State “Full Synthetic” oil, and cut costs that would ruin the oil. Fortunately, as it turned out, that did not happen. And in fact, now this latest new 5W30 Quaker State “Full Synthetic” motor oil, is BY FAR, the BEST PERFORMING motor oil that I have ever tested. This is absolute proof that Quaker State REALLY knows how to formulate motor oil.

This new “Full Synthetic” motor oil has set the bar so high, that it is the oil I will be using in my own vehicles from stock to High Performance, from now on. And it is the motor oil that I will recommend to my Blog readers for most water cooled, gasoline powered engines, that can use 5W30. This is especially THE “go to” motor oil for traditional flat tappet engines to provide the utmost in protection against wiped cam lobes.

Never say never, but it is hard to imagine another motor oil ever producing numbers this amazing.

Here is a back to back comparison of the new 5W30 Quaker State “Full Synthetic” and the old 5W30 Quaker State “Ultimate Durability”.

NOTE: The Higher the psi value, the Better the wear protection capability. And the Higher the onset of thermal breakdown value, the Higher the oil temperature can reach before the oil begins to deteriorate due to heat.

QSFS at 230*F = 152,674 psi
QSFS at 275*F = 148,133 psi
QSFS onset of thermal breakdown = 290*F

*****
QSUD at 230*F = 133,125 psi
QSUD at 275*F = 115,764 psi
QSUD onset of thermal breakdown = 275*F
.
The only possible concern about this amazing new 5W30 Quaker State Full Synthetic motor oil, was that it might be “too good” for use in wet clutch motorcycles. But, motorcycle Owner feedback in July 2021, proved that this amazing new motor oil works just fine in wet clutch motorcycles, meaning there was no clutch slipping at all. Of course that applies to wet clutch motorcycles with clutches that are in good condition."

Erich Swafford

As someone else mentioned, Castrol GTX 20w50 is the oil I’ve been using in my older German cars (BMW E30, Porsche 944) and it’s never failed me. The E30 is at 180,000 miles without needing anything other than routine maintenance.

I’ve been using this oil since 1984 when it first came out. There has to be a reason it’s still in production!