Read the API service specs on the back of the containers: NA & turbo gas fueled cars require SJ, SL, etc spec .... and all 15W-40 Diesel oils that meet the required CG4, CF4,etc ...ALSO meet the SL spec (CF/SL). This is true of both dino and syn lubes of good quality.
So, where's the problem?

 

As I said its in my truck and no worries; just passed 100k kms but I use 15W40 oil for my Duramax Diesel Engine not in my 928. YMMV.

Mobil 1 for year's..............no engine troubles at all. (no curses pls.)

 

In retrospect perhaps I can get a better deal on deisel engine oil than anything else and run both tractors the truck and the 928 on the same stuff.

Who do I blame if the 928 engine blows @ 240kph? UFA? If the engine doen't blow then I got to believe that Mobil 1 and all the rest are screwing us, $ wise..............and that wouldn't be a surprise.

 

Malcolm,

Where are you buying your M1? I am running M1 15-40 and although I don't need an oil change yet, I couldn't find supply anywhere here in Edmonton to have on hand for top up or next oil change. The Parts Store tells me they can't get it anymore.

I know M1 is the heralded favourite on this forum but is there an alternative?

 

This is exactly why I recommend against it. I have taken apart a few engines that the owners admitted to using pennzoil in. They ALL looked like somebody had poured some awful black, waxy goo in them. That stuff sludges up so fast it is scary.

 

I find the comments about pennzoil interesting.I've been using it in my "new" 1983 z/28 since I bought it on march 18th @ 8:45 PM in 1983.I changed the oil the next day to pennzoil hd-30 and have used it ever since.Thats over 23 years ago.Engine still looks like new inside.I was just starting to think about using 15-40 rotella in it due to the zinc being taken out of normal engine oils and the fact that it is a regular old style sliding lifter camshaft.Thought about changing over the 928's to it also for the same fact,but its also going to be discontinued soon in small containers,may have to start to buy it in 55 gallons drums.

 

I would never use Penzoil in my 928. However, my dad swares by it, and has used it since before I can remember. He has owned Hot Rods all his life, including a very rare 69 Yenko Chevelle which he let slip through his hands back in the mid 80's. Growing up around Penzoil all my life, changing the oil in his hot rods, checking the oil, ect...I noticed one thing. That this oil turns dark brown/black much quicker than any other oil I have used. But, I have torn down several engines with my dad (none due to failure), and all were clean as a whistle inside. He always changed the oil religiously at 3k no matter what. IMHO, if you neglected regular oil changes with any oil, but especially penzoil, sludge is going to build up. Some oils just take longer for this to happen, especially synthetics like mobil 1. Just for the record, I use Shell Rotella 15w40 in my 928.

 

You can do some searching for previous posts on this subject and find a bit more info.

For many of my early Porsche years, Pennzoil was the brand that dealers supplied. In the air-cooled cars especially, engines run on Pennzoil were routinely suffering from oil-related failures. On tear-down, there would be a thick gray sludge in the sumps and/or tanks. There was some discussion at the time that included oil not getting hot enough to flash off condensation from combustion, stuff like that. Meanwhile, those of us that had grown up on Castrol in our race engines had no sludge problems.

Since then, I suspect that Pennzoil has improved their formulations once or twice. There's probably a little less wax/parrafin in the oil these days, so maybe the gray sludge in the sump is also a thing of the past. Makes no difference. I inherited a bottle of 30W Pennzoil from a neighbor a few years back. It's OK for chain bar oil, but will never make it into an oil sump I own, not even the lawnmower.

My standby generator gets Mobil-1. Pressure washer gets Mobil-1. Lawnmower gets redline grease on the clutches/dogs, that's about all. It's a push-mower... We have a few acres, but the grass is only 20'x20'. Rest is rocks and brush

 

Doug............M1 is available through WalMart and Costco as is Castrol synthetic.

BTW, I'm headed to Spruce Grove on Sat...........want to do coffee somewhere?

 

I thought the pennzoil issue started back when they used ash in it?

 

My understanding of oil turning dark/black was that the detergents where holding contaminates in suspension.Oil is suppose to turn dark with use.Its when the oil can no longer hold these contaminates that they drop out of suspension and start to coat the internal parts.Even the mobil 1 that I use in my chevy truck engine turns dark with use.The castrol 20-50 that I use in the 928's turns dark.The castrol 20-50 that I use in the M-B 300 diesel turns black as hell in 2500 miles,but engine is clean as a whistle when I pull valve cover to do valve adjustments on it every 30k miles and that vehicle has almost 400k miles on it.Sludge happens from poor maintanance and IMHO changing oil brands at every oil change and/or shopping for the lowest price oil change everytime you do one.Hell...I've even seen Quaker State NOT sludge engines when the oil is changed on time. 30 years of fixing cars has shown me that almost all sludge problems are from improper maintanance,not brand of oil.The biggest problem is that most poeple think that they fall into normal usage when they are really severe service and should follow that time table for maintanance. Most all vehicles are operated under severe servcie conditions except the ones that people think are sevre servcie,ie cop cars and taxi's,as they run almost all day long after being started and the engines never get a chance to cool off between restarts.
I am getting ready to change all of the cars/trucks that have sliding lifters/cam followers over to rotella diesel oil just because of the removal of zinc from conventional gas motor oils,may even buy a bunch of 55 gallon drums to hold me over the next couple of decades.

 

I use castrol full synthetic 20-50 and change every 3K but here is what i found on the cd the other day, more porsche confusion;

 

tv - all 3 variations have unique oiling properties and therefore difference weights within each "class" of oil. Typically we're talking Synth for our Sharks, so you'll notice nothing greater than 10w on lowest number (many run 15w-xx M1 and it's okay if weather never gets too cold).

Think of this chart as here's the best recommendation for each class, ALL intended to provide the best oiling coverage for that class' capability.

 

Looks like it's good down to about 5F. That's pretty cold.

 

Chris - you're referencing the Multi-grade chart, not the Synth chart

Consider that it ISN'T on the Synth chart, because there's more flow/better oiling from the lower 5w/10w weight and the 50 higher/hot number is still covered...essentially the Engineer is saying, "Why not get better flow (especially cold/startup) with the same hot 50 weight coverage".

Don't get me wrong, 15w-50 M1 - great oil, although IMHO a 5w makes more sense for cold/startup coverage.