I used Castrol 20W-50 GTX for 30 years in cars and motorcycles. No problems. Three cars went over 250k miles each. Then I got a a couple of 5 qt jugs that looked like 90W. I tried it in one BMW and the Volvo and they both sounded awful on cold start. I sent a sample in to BP (owner of Castrol) and they tested it and reported that it was "within blending specifications". I asked if their specification is simply "will pour out of the jug".

Switched to Mobile 1. Problem - I cannot keep it in the engines. I have changed valve cover gaskets in both '97 328 BMWs. Changed valve cover gasket twice in the '91 245. All three still leak. One of the '97s leaks badly. Tonight the wife came in complaining that her 2004 BMW smokes and stinks. You guessed it - leaking valve cover gasket.

This is ridiculous. I have to switch to a different oil. The '97s and the '91 can go back to dino oil, bu the 2004 has to be synthetic.

What do you folks use?

I usually buy the oil at walmart , I pick whatever top brand synthetic is cheap, in last couple of changes I have used , Castrol syntec 10W40 (current), Shell Rotella 10W40 (last used) , Mobil 10W40, Lets see which way they lure me next time otherwise I want to try regualr GTX. I change oil twice a year with around 12K miles per year. I do have a minor leak at rear main seal.

Regards,
--
DD-1990 240 DL SW M47II FI 3.1 234 K miles

IMHO, and practice, I would never change from long term use of dino oil to a full synthentic. 160K in '88 200, 10w30w Castrol from Walmart, change every three months with filter, it's right in the owners manual. Even at 15 below this winter, with 10/30 it cranked and started almost immediately, however, well tuned.

If an oil viscosity of 20/50 is used, in my opinion, the thicker viscosity will lubricate less than required at the most clearance critical parts of the engine.

I would stick with one brand once started. If in the future I detect some oil consumption I'll change up one weight to 10/40. That's my two cents.

I have been using dino oil for most of my car's 25 years. Last fall I finally went full synthetic (Mobil 1). No leaks that I can detect. Now I only have to change it once a year.
--
Mike F - 1984 244 DL - 285,000 miles
Original engine, transmission, drive train, starter
Undergoing reconstructive surgery with POR-15

Hi LordVolva:

I can agree with you for a once a year oil/filter change with full synthetic if and only if your total miles driven is less than 5K and in normal conditions. No towing, no extreme heat, etc. Even with sythetic the carbon, acids, and metals ejected during operation will degrade the lube and cause wear.

I think you are pushing your luck otherwise.

What do you other guys think?

walmarts supertech full synthetic 10/30....5 quarts for 17.50.

it is made by pennzoil and is the same product as pennzoil platinum full synthetic.

walmarts supertech oil filters are actually made by champion

If you have incurable leaks, sounds like it's time to check the PCV systems. Synthetic oil should work just fine with good seals.

I use 10W-30 Mobil 1 in all of our Volvo's. For me, longevity is moot. I just like not having to change the oil so frequently. :-)

-Ryan
--

Athens, Ohio
1987 245 DL 324k, Dog-mobile, E-codes
1990 245 DL 137k M47, E-codes, GT Sway Bars, GT Braces, Dracos
1990 744GLE 189K 16-valve project
1991 745 GL 304k, Regina, 23/21mm Turbo Sway Bars

I just took out that flame trap couple of weeks ago and replaced that S tube with 8" long 15 mm ID fuel hose. I hope no back fires occur.
Regards,
--
DD-1990 240 DL SW M47II FI 3.1 234 K miles

A new valve cover gasket will not leak when properly installed regardless of the brand of oil. You going in the wrong direction I think and besides I can predict you will get at least 25 answers each with story and a different oil brand, type, viscosity, whatever.
--
David Hunter

I got 400,000 miles out of a Chevy S-10 on a steady diet of Valvoline 10W40 and Fram filters. No leaks, never burnt much, body fell off the frame. Now I'm using Rotella 15W40 in my '87 245 and NAPA synthetic in Mary's '04 V70 2.5T. No leaks, never down between changes.

Your mileage may differ.

Greg

I've been an Amsoil user for 30 years now. Their 5w-40 European spec formula (Product code AFL) is a good product, and on my higher mileage (340k+ vehicles) I use 15w-40 Diesel and Marine oil, (Product code AME) which is quite a bit less expensive, especially when purchased in 2.5 gallon containers. They also have a full line of other synthetic and semi-synthetic lubes that I've had good results with. (ATF and gear lube, to name a couple more) With regards to your valve cover issues, the only thoughts I have are to start with a new gasket from a reputable supplier, and torque the cover down very evenly in small increments until you are at the manufacturer's torque spec. You might use a thin film of black RTV on both surfaces and let it skin over a bit as well before assembly. Due to the high detergent properties of synthetic oil and its uniformly small molecular size, it does want to find its way out of places that mineral based oils cannot go.

Castrol 10-40 GTX in everything.

Motorcycle, lawn mowers, snow throwers, all my cars.

I have 300K on 3 of my cars. Original owner of two out of the three.
The motorcycle has 60K miles on it, bought it with 4000 miles. All Castrol, all the time.

I have always been reluctant to switch from fossil to synthetic in an "older" car due to the possibility of leaks. 2004 isn't older for a BMW and in fact I think synthetic was recommended by BMW. BUT in my 88 245 with 200k miles I stick to a name brand fossil with good results. For a long time I used Valvoline. Recently I started buying my oil at Walmart. I switched to Castrol GTX 10w-30 last summer and 5w-30 in winter even along the SoCal coast with mild weather. No leaks.

As an aside, BMW recommends the LL, synthetic "long life" designation for the 2006 530i. VERY expensive and not stocked in most stores, only specialty performance and dealer$.

--
1988 245A. Past: 1979 245A; 1987 244 M47; 1971 164E

I got a response on a BMW forum from a fellow who calls himself CoolBear. He had a similar experience to mine - used GTX for 30 yrs, then tried Mobil 1. He said that it was as though he had put blood thinner in his cars - they all started leaking oil. He went back to GTX.

That was my experience as well. I put Mobil 1 in my Toyota 4-banger and it started leaking oil. Went back to dino. Not saying Mobil 1 caused the leaks, don't want to upset anyone. Just saying it didn't leak with dino and it did with Mobil 1.
--
1986 Volvo 245

here in alabama i use rotella 15w40 year round. no problems in my '94 940 and '90 740. have considered going synthetic, but i'm kinda old school. maybe somebody can talk me into it.

Hi Russell,

Your initial comment about how dark the oil was had me remember a past oil issue. Typically I purchase my oil at Walmart. Sometimes Pennzoil, Mobil 1 if on sale or the Walmart brand Lubritech, all 10/30 synthetic.

About a year ago, when I took the cap off a jug of oil, I didn't notice how dark it was until I got to the bottom of the jug when it became apparent from the debris that it was a used jug of oil.

I complained to Walmart and they were very good about compensating me for my loss as I had changed the oil in two cars from that jug and had to replace oil and filter again.

Although this may not apply to your situation, the lesson I learned is make sure the safety seal is securely on the top of the jug before you start pouring.

Apparently, some dogs take their used oil and bring it back to Walmart for returns.

Glad the BB is back up and running.

Marty Wolfson

whatever cheap synthetic 10-30 or 5-30 i can get my hands on.

Castrol GTX. 10W-30 normally. 5W-30 in the winter in snow country. 15W-40 in the summer in Arizona and Nevada.
--
1986 Volvo 245

castrol gtx 10-30 or thicker in summer/long trips, feel free to blame synthetic for leaks made my 98 civic toyota 22r and one of my 245s leak. high mileage oil can tend to gunk oil ports in the long run but they do help with smoking/leaking
as far as the filter i try to stick to oem but i prefer purolator for the money

After changing the seals and gaskets on my 75K engine, I changed to Mobil 1 5w30 with no leaks or problems.