Can I use GC in older BMWs

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Dec 4, 2004
Lexington, KY
I generally see mostly 40 weight oils specified for older BMWs. My 1995 BMW 525i with 2.5 litre M50-TU engine owner's manual (and Bently manual) only indicates 30 weight oil when the temerature stays below 40 degrees. The car has 119,000 miles. I assume age/wear affects oil viscosity needs as clearance increases with wear? For example, my mechanic likes 15w50 Mobil 1 in my car Just a bit confused. Cn I saely use CG in my car winter and summer? TIA
Have used 30 weight GC (a thicker 30 weight), Amsoil's thicker SAE 0W, 5W, and 10W-30's and now their 5W-40 (better). Amsoil has held up well when run the full distance of the service indicator in these engines. A lot would depend on the condition/maintenance history of your engine and mileage. Does it consume much if any oil? I would be inclined to run 0W-30 GC year round if no consumption issues or Amsoil 5W-40 year round. Amsoil has thinned some of their 30 weights recently, so I am moving away from them, especially in higher mileage engines. Mobil 1 has been on the thin side of a 30 weight oil. I like their 5W-40 T&SUV oil in these engines however. The 15W-50 will work fine also, but I would not use in winter. May also lose some mpg with a thicker 15W-50 oil. Redline is a very robust oil for these engines, but costs more.
BMWtechguy, Thanks for your comments No use of oil between changes up to 4,500 miles on any oil used in this car. I am onmy second Auto-rx treatments. UOA from Blackstone/Dyson prior ro arx treatments shows up 23 ppm lead and fuel dilution. Changed air filter/plugs, check for vacumn leaks etc. trying to reduce dilution and lead. Car seems to run well, excellent fuel mileage and seems strong. Just want to go to an excellent oil for use here in central KY
I want to add that the Schaeffers #9000 synthetic 5W-40 looks like an excellent oil that beats all the other synthetics on price and possibly wear protection. Decent fuel economy too. Read around here on BITOG about it. "Hammer" and many others have used it with good results and someone recently ordered a case of 6 gallons for $90, which works out to $15/gal shipped to your door in a couple of days. That's the next oil on my list to try in BMW's. I will be contacting the site sponsor, of course.
I am using GC in my BMWs: '95 M3 '91 318is '90 325is None of them leak (well, the 318is did before using GC but I have recently freshened all the gaskets so no more leaks and am now using GC as the first fill after freshening that motor). Then again, the M42 motor leaks like a sieve with it's bizzarro design and it had 200k miles on it when I pulled to freshen the gaskets (compression was still over 200 psi on each cylinder with all original motor so I left the bottom end alone other than oil pan gaskets, etc.). I used to use primarily Red Line and some Royal Purple previously. I will use up my stash of GC now. Regards, Rich
Russell, My experience for over 20 years with the same car is you can use 30wt. oils, if you take it easy. What fun is that? GC is OK, 15w40 is fine, almost ideal but, 5w40 is best. Mobil 1 15w50 is a bit thick in cold weather but, great for high speed and the track, Overkill maybe.
GC is a A3 rated oil that is approved for use in place of BMW's own LongLife -01. I wouldn't hesitate to use it! Next oil change my '02 330ci is going to get it (it has had only M1 0w/40).
I have used it successfully in my 1894 BMW problems...well, except for the spider's nest in the glove box...
5w-40 oil is optimal Im using rotella 5w-40 in my 91 318i M42 engine, and UOAs come out perfect. JMH
I'm not using GC, but switched from M1 15w-50 to M1 0w-40 about 2 years ago in my Wife's 1994 525i. I noted quicker startups, no lifter noise anymore, and lowered oil consumption. 15w-50 is to thick for the newer hydro lifter motor BMW's for almost all use. I say try the GC, you will probably like it.
Quattro Pete, The dealers use BMW High Performance Sythetic 5w-30. It is a castrol group III "synth". It has showed some decent UOA's on this site, even run to 15k miles.
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