Don Carter

Interesting that when the oil guru Doug Hillary stated he was using 5w-40w in this thread from 2003, noone posted that it was too thin.

Last time I changed oil, I re-read some of Doug's posts and ended up with M1 Turbo Diesel Truck Synthetic 5-40. I have 3.75-4 on the oil gauge at idle dipping to low 3's when in gear with the AC on, engine warm.

Not sure what to think at this point... leaning towards a heavier oil at the next change after reading this thread.

Maleficio

I'm very reluctant to install 20W50 oil because of bad experiences in the past. I was running Amsoil 20W50 racing oil in my 87 VW Golf with an Amsoil oil filter. The car ran absolutely great on the thick oil, but on three separate occasions I fired up the car cold, and the oil managed to squeeze past the oil filter gasket and pour onto the ground, nearly the entire sump would dump out before the oil pressure light would come on and me shut off the car. Was this an Amsoil oil filter problem? Too resistant media in the filter can? Bypass mechanism not opening for cold flow? Three different Amsoil filters, three different occasions, and yes, the filters were all screwed down tight.

This was fifteen years ago, and I was running Amsoil oil and Amsoil filter. I've been very leery of using 20W50 since that time simply because I'm tired of carrying an entire sump's worth of oil everywhere I go just in case I dump the crankcase again because the filter refused to flow the cold oil.

86'928S MeteorGrey

Wow. That's extreme. I'd imagine it was a filter problem, or some other mechanical defect. You can rest assured that 20W50 is not going to do that in your 928.

GregBBRD

Happens all the time...very common. All of us that use or sell 20/50 always send an extra 9 quarts with every car we work on...just for this reason. Interestingly enough, always seems to happen in Walmart and K-Mart parking lots...which is why those places always have huge oil slicks in the middle of every stinking parking spot.

This thread just gets better and better. God, I love Rennlist.

Maleficio

Thanks for the mockery. I'm really enjoying your contributions to my thread.

robot808

Well, I don't know Greg. I do know that some of his posts upset people. I also know that he does incredible work with these cars and knows more than most on this board about them. I am not saying you have to like him, but if he ever suggested something to me about my car, I would definitely take his suggestion very, very seriously.

Dan87951

I use Shell Rotella 5w-40 in the colder climate and have had no problems. Runs great. Makes wonder if we have a lot of tired engines on this forum with such big variances in how they run with a simple oil change. In the summer I do run the 15w-40. Porsche recommends 0-40w anyways..

robot808

For 82's:

GregBBRD

Yes, sorry for being a butt. Should not be that way.

Here's some legitimate thoughts about your oil/experiences:

1. There probably isn't anyone on the planet that is sensitive enough to tell the power differences between different grades/types of oil. The horsepower differences are so small that they are well with-in the "error" percentage of all but the very best dynos. Ignore the oil commercials. They are marketing using anything they can use. That being said, some oils do "wipe" better off of the cylinders than others. This can effect combustion (less oil in the combustion chamber) and it is possible that an engine might run smoother.

2. Your oil filter issue was probably just that (most likely). However there might be another explaination. I have seen some older racing engines that would "blow" the oil filter off when the oil was thick and very cold. 427 Ford engines were famous for this. The reason this happened was that these engines required a lot of oil pressure, when hot (100 psi). This required a very stiff spring for the oil relief valve. When cold, there was way too much oil pressure and the filters would simply blow off, if the engine was not properly warmed up. This might be what happened when you had problems running 20/50. You could have had a pressure relief valve that did not work properly and this caused the seal to blow out of the filter.

3. These 928 engines are older designed engines. They do not like the newer, thinner oils, because they were designed with different clearances/pieces. Your current selection of oil will probably/should work fine through the cooler winter months, but you should seriously change it to something thicker before the weather turns warm, again. Try a 15/50 or a 20/50, in your favorite brand of oil. Makes sure that that brand has elevated (at least 1200 ppm) levels of zinc and phosphorus, to protect your camshafts.

4. Walmart parking lots always do seem to be a huge oil slick. Why is that and why can't they clean that mess up?

Again, sorry for being an ***.

Maleficio

No problem, Greg. Thanks for the superb advice.

Maleficio

Haha.

robot808

Gary,
Perhaps re-read my comment. I think you have misunderstood it.

EspritS4s

Well, I guess I'm confused. Wouldn't be the first time.

robot808

The post was all about Greg.


Edit: Yeah, I've got no idea why Maleficio is doing some of the stuff he is doing to his car, but it's his car and in this great country of ours, he can do whatever the hell he wants.

Maleficio

Installing factory plugs fixed an idle rumble.

Wrapping the intake tubes fixed a hot air intake problem during stop and go traffic.


I didn't change oil weights in this oil change, just brands and purpose. I had a 50/50 mix of RP 10w30 and 10w40.

Now it's a non-mixed weight.

I like how the car's running with this collective implement.