I was at the local Wal-Mart this past weekend and they had 5qt containers of 15w-50 Mobil 1 for just $18.88, so I bought a few. Although, after reading my manual and the FAQ it seems that this may or may not be useful. The car in question is a '92 745t with 120,000 miles on the clock, just had the warped head stretched and milled and all put back together looking spiffy & new. It overheated when a collant hose burst!
Should I dumnp the dino oil the mechanic used (Castrol) and use this 15w-50?

I also replaced the 3 front oil seals. I was previously using Mobil1 10w-30 but have only owned the car for 12,000 miles - I knew the seals would leak when I switched and that they'd have to be replaced.

Won't this be a good summer oil? with temperatures in the Philly area usually peaking out at 90 - 95 degrees F

What damage could this possibly do?

Ian

I have an '87 740T with 224K miles on it(original turbo); I use 15W50 Mobil 1 'cause, compared to 10W30, the pressure is better and it doesn't burn ANY(0). With 10W30 Mobil 1, which I use in my 245 with only 150K miles, it burned about 1 qt./1500 miles.

The 15W-50 will work fine. It will run a bit hotter and have a bit more internal resistance than would an xW-30 Mobil 1.

A 15W50 should be fine, a lot of oil makers recomend thicker grade oils for higher milage cars, and 15W50 will handle higher temps than an 10W30.

10W30 oils were originaly considered the oil to use to get the best possible fuel economy, many car makers recomend them just for that reason, and there really is nothing wrong with using a thicker grade oil, particulary in an engine that is racking up the miles.

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My 85 760Ti, and her name is Veronica...

I've been using 15W50 Mobil1 in both my Bricks from spring to fall for the past 2 years. 740 & 940 turbos. 221,00Km & 165,000Km. No problems. Mobil1 kept a 7 second turbo drag bike alive for a season, must be good stuff. This was when the throttle was chopped at the end of the strip w/ the turbo at full boost. So the only lube it saw was what was in there at the time. It has to have good film strength.

As for Castrol, I think you will find the general opinion that it is crap.

Do you have data to back-up the Castrol/crap statement? Or do you mean dino v. synthetic? Not being argumentative, just curious. I have used Castol dino for years with good results. Thanks for the info.

I agree about the Castrol and that's why I want to get it out of there. I'll probably switch over to the Mobil 1 this weekend then.

Ian

I started using Castrol 35 yrs. ago in motorcycles and a variety of 4cyl.6cyl.&8cyl.cars. I've worked at several motorcycle dealerships since 1975 and they've all used Castrol GTX in new & used bikes. At one shop we sold Honda,Kawasaki,Yamaha,Suzuki,BMW,Moto Guzzi etc.Factory service reps recommended Castrol. Most motorcycle engines share engine and trans.oil which is damn hot and under extreme pressure[transmission gears],plus they're spinning at 10,000-15,000 rpms[not 3,000-6,000].I find it hard to believe that Castrol is crap,I do agree that you can use either 10w30 or 15w50 Mobil-1 year around.

I read some bad things about Castrol Synth, but I beleive their regular oils are fine, and good value for money, did well in many cars I owned in the past.
But then I've not used castrol in a long time.
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My 85 760Ti, and her name is Veronica...