Seattle 993

Jimbo, those leaks occurred at about year 12 of the vehicles life - like I said a long time ago and about a year or two after the Mobil 1. But yeah, I generally agree that reseals are a fact of life with any car.

MAGK, do you recall when Porsche recommended European formula 0w-40 for all cars? I think it was light on Zinc also, and there were experts (Steve Weiner comes to mind - he owns a well respected shop in Oregon) that saw customers reporting problems in their flat tappet 911s. Now that is an expensive engine to repair...

Fortunately, 944 engines are rather benign.

rlm328

The synthetic oils have a more uniform molecular size than the dino oils. If you have a recently resealed engine I would use the synthetic oil, if it has not been resealed I would use the dino oil as the different sized molecules tend to bridge better in the seals. The 944 engine was not a real high tolerance motor to start with and after some age and seal wear it does not get better. The one bad thing about the VR1 oil is that it will tend to sludge in the oil pan. The zinc in the oil is there for additional lubricant for the lobes on the cam and lifters.

MAGK944

...and then there is that green oil Brad Penn semi-synthetic which I’ve used for years on my non-track driven 944’s, maybe the best of both worlds idk, it’s certainly been a popular high-ZDDP choice for many on this forum particularly in 10W-40 and SAE 20W-50 grades.

rlm328

I also use the Brad Penn oil, and I am presently trying the Motul Oil. I am in the process of getting a baseline, I will send out for labs every 2 or 3 track events. I was trying to stay away from brands as that goes down a complete other rabbit hole.

Sveina

Lubrication Engineers from Ft. Worth, TX. Using Monolec 5/30 or 20/50 (depends on track usage) for years. Changed out the Mobil 1 (EU formula) to the LE 5/30 in my 996 turbo, and it suddely was silky smooth. With LE 5/30 on the 951 the engine is so smooth that I have never heard any 944 sound so good mechanically, and the engine has over 200.000 km on it. And I've been around these cars and owned alot of them the last nearly 20 years. Good patented additives > ZDDP any day.

jimbo1111

Im just surprised porsche recommends a 4T motorcycle oil. I just recently ordered it and plan on testing it to see the lab results.

V2Rocket

Zddp is only relevant for the cam and lifters.

Oil viscosity is what keeps your crankshaft off the bearings... porsches chart only recommends 5W30 with a maximum temperature of 0C/32F...it doesn't get that cold in DFW

How many times does someone have to write on the internet...20w50 if it's not currently snowing?

George Boss

FWIW, my 89 951 is still original, all the seals are original, and doesn't leak any oil. I've tried M15-50 originally (way back in 96), then went to Castrol 5-50, then Amsoil 20-50, then Aggip 20-60, and now Redline 20-60 over the past 23 years. Reason for the changes are that I always found the car burned the Mobil and Castrol a bit more than I liked; the Amsoil made it run a bit hotter than usual. The Aggip and the Redline keep the temps down and don't burn as quickly as the M1 or Castrol.

All these were synthetic, BTW

Dan Martinic

After a brief try at 10w40 last winter, I'm back to my Liquid Moly 10w60 but now I put their grey additive in as well. Available locally, it doesn't burn and it keeps pressure up to spec. Daily driver all year round ten years now