Engine Oil For Dummies

[johnb]

Maybe I just have lower standards, but I wouldn't do anything special for the winter. I live in Indiana so I have basically the same climate as you. I don't think my car has suffered much from years of living outside in the winter, and being driven too. There are plenty of days when the roads are dry. If you can drive it once a month that's plenty. I think the most vulnerable part on mine is the mild steel exhaust I put on it about 10 years ago, and that is still totally fine. The bodies don't rust like other cars do.

Synthetic 15w50 might be a good choice for cold winter starts.

[AudiSport]

Most commonly used with our flat tappet engines is Castrol GTX or Valvoline VR-1. High zinc content is the main priority though. I personally run valvoline VR-1 20W50 in my 2.5L.

Casrtol GTX is no longer high in zddp -- actually on the low end with 610ppm. They now have Castrol Classic GTX, however, with 1310ppm (per google). Here's a nice list of some high-zddp oils, courtesy of ChatGPT:

AMSOIL Z-ROD 10W-30/20W-50, ~1430 ppm ZDDP
Valvoline VR1 Racing (conventional), ~1400-1500 ppm ZDDP
Motul Classic Performance 20W-50, >1800 ppm ZDDP
Lucas Hot Rod & Classic 10W-40/20W-50, ~2100 ppm ZDDP
Driven Racing Oil HR Series, ~1600 ppm ZDDP
Mobil 1 Extended Performance 5W-30, ~900 ppm ZDDP
Castrol GTX Classic 20W-50, ~1400 ppm ZDDP
Pennzoil High Mileage 10W-40, ~800-900 ppm ZDDP
Shell Rotella T4 15W-40, ~1200-1400 ppm ZDDP
Shell Rotella T6 5W-40, ~1100-1200 ppm ZDDP
Summit Racing High-ZDDP 10W-40, ~1500 ppm ZDDP

I've run the Rotella T6 in my twin turbo Audi for a while. Mostly lately been using Mobil1 Euro car 5-40 it's at the 1000ppm ZDDP which is in spec also for Porsche. I just did a oil change on it and switched to that.

[333pg333]

I'd follow Tom's advice. Mineral oil with plenty of ZDDP. Consult the owner's manual too. If you don't drive it in Winter what are the general ambient temps when you do drive it? If it's generally warm to hot in Summer then I'd avoid a low 0 - 30w or 5 - 40w weight oil. They get too thin when the engine is hot and these motors do get hot in Summer.

[AudiSport]

I'd follow Tom's advice. Mineral oil with plenty of ZDDP. Consult the owner's manual too. If you don't drive it in Winter what are the general ambient temps when you do drive it? If it's generally warm to hot in Summer then I'd avoid a low 0 - 30w or 5 - 40w weight oil. They get too thin when the engine is hot and these motors do get hot in Summer.

Oil weight doesn't equal shear stress capability and sometimes higher weight range makes it worse due to the viscosity additives that break down easier.

[Latitude48]

FWIW (which isn't much I guess), I've been using Redline 10W40 High Performance oil in my 944 S2 for 28 years. Google claims it has 1350 ppm Zinc and 1230 ppm Phosphorus. When I was driving the S2 back and forth to work I would change oil every 10K miles and during that 10K the engine would use at most 1/2 Qt. Discussing oils is kinda like discussing politics and religion as everybody has their own opinion what is "correct," so pick one you like and you'll be fine.

[spacecad3t]

On the winter topic. My 944 lives on the street in a quiet neighborhood in Brooklyn. I try to drive it as much as I can over the Honda, and nowadays NYC is fairly "clear" all winter, just bitter cold... I usually have all the cars washed here and there during the winter and detailed come spring.

I also have a 68 Mustang that is parked off street, covered, but "outside". It has been 10 years that way and it went 4 years, I didn't touch it... very sad, but ¯\_(ツ)_/¯ she fired right up and I changed all the fluids, that was 3 years ago. Now, we try to drive her once a month and I'll take her out on those sunny winter days too. Cars are tough.

[16v951]

Longtime owner of two 944 Turbos in the Midwest. Both cars are stored winters and only use VR1 20-50. One car sees lots of track time and now has had multiple proactive rod bearing changes. Each time they have been changed they look nearly new (could be the oil, could be luck).

Both cars are stored in the winter with fresh oil/filter, dryer sheets in common mouse areas, and a nice wash/wax. They are not started until spring. When I get them out for the first time in spring, I always make sure to pull the DME relay and crank them over until get oil pressure. Once that happens I put the DME relay back in and start them up. It's worked well for me so far.

[Thom]

What does everyone think about using a dino oil like the VR1 with a ball bearing turbo?

[944m3]

No love for Millers NT with ceramic nano tech?