Hi Guys,
Just got my username registered here this evening on BITOG. Am a member over on Bimmerforums, as I have a 1993 BMW 320i.
Basically, I've joined here since I've spent so many, many, many hours reading hour I felt it might be time to give something back. I'm also curious about posting UOA's when I start getting them done.
In this post, I wanted to evaluate the potential pros and cons of extended drain intervals. My car has nearly 120K miles (193,000km) on it, and until I got it 12.5k miles (20K km) ago, it was serviced only according to the service lights, which time out at a maximum of 10K miles (16k km) on this vehicle.
The actual run it would have had on that change, with mostly highway driving was 7.5k miles (12k km), however I chickened out and changed the oil at 5k (7.5k km) to be safe with M1 0w40.
That oil did run 7.5k miles, during which the service indicator 'tripped,' and I recently switched over to Rotella until I can get the car in for some work, which substantially quietened the valvetrain, but the engine still ticks constantly when warm (thinking the chain tensioner is the root cause).
{I have a short video of this I can post if necessary}
Anyway, with the work that will proceed, that car will have another oil change. I tried a lot of searching, but haven't found a lot of UOA's on this age of BMW where people have bothered to stretch out the interval to around 10K. Those that have look promising, however, I'm concerned about sludge buildup over the long run. There was one post with an engine on the 15K interval for many years that looked pristine. But I'd prefer more than the odd anecdote for my own "comfort."
Looking under the oil cap, I've just managed to catch glimpses of the head, and it looks only slightly varnished. Since the VCG is leaking*, I'm hoping my shop will take some pictures for me during the process, so I can evaluate whats been going on over 21 years of 10K intervals...
*The VCG started leaking after the switch to M1, am thinking the P.O's mechanic used dino oils. The lower chain tensioner also appears to have leaked since then...
The best thing I can do, I guess, is to start off with the oil, and take a sample halfway through the interval, and see what Blackstone have to say, and go from that. But the OCD inside of me wants confirmation first, LOL.
Have also noticed, while researching BMW Special Oils, in particular (the old, old specification), that many -50 hot weighted oils were approved for use back then. This then seemingly slipped to a 0/5w-40 (thick 40, like Rotella), before settling into the Thick-30/thin-40 ratings of today. Based on this, it seems as though almost any modern oil would meet the necessary certification needed for our older M50 engines!
Personally, I was planning either German Castrol for my DIY changes or just M1 0w40, as both (particularly the latter) seem to have very good extended drain capabilities. Even though M1 makes my poor engine tick like a watch factory... Suggestions are welcomed here!
Apologies for the long post, in no sense am I the sort of person who does stuff "briefly." I like to have all the answers to my questions, to feel comfortable that I'm making a sensible and right choice. Thanks to everyone who has suggestions to my problems. And thanks to everyone who posted in the past, all the information here has been quite useful.
Information on Extended Drain
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A UOA will tell you how a particular oil is fairing and possibly if there are excessive contaminants which could be from a variety of sources. For example, unfiltered air, cleaning sludge, a bearing that is really wearing, head or other gasket leak.
In general a UOA is not cost effective, better off running a quality synthetic oil to 7K or 8K miles.
Good luck and welcome.
Hi and 
What oil brand and grade were you using before the change to M1 0w-40 ?
What oil brand and grade were you using before the change to M1 0w-40 ?
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I would run the Castrol 0w30 over the M1 0w40. for some reason M1 seems to transmit more mechanical noise. Other than that both are excellent choices. Have you considered Rotella 5w40 or Mobil1 5w40?
Originally Posted By: virginoil
Hi and
What oil brand and grade were you using before the change to M1 0w-40 ?
What oil brand and grade were you using before the change to M1 0w-40 ?Originally Posted By: doog
I would run the Castrol 0w30 over the M1 0w40. for some reason M1 seems to transmit more mechanical noise. Other than that both are excellent choices. Have you considered Rotella 5w40 or Mobil1 5w40?
If you are looking for cheap transportation, a 93 BMW isn't the first place to go. I'd say "extended drain" is penny wise.....
How long of an extended drain do you want to go?
12-16k km (7.5-10k mi) will be perfectly safe with synthetic. Especially in a warm climate like Australia with highway driving.
On a 20+ year old car and with unknown maintnance I wouldn't stretch it out to 20k or 25k km though.
Originally Posted By: HerrStig
If you are looking for cheap transportation, a 93 BMW isn't the first place to go. I'd say "extended drain" is penny wise.....
Originally Posted By: camrydriver111
How long of an extended drain do you want to go?
12-16k km (7.5-10k mi) will be perfectly safe with synthetic. Especially in a warm climate like Australia with highway driving.
On a 20+ year old car and with unknown maintnance I wouldn't stretch it out to 20k or 25k km though.
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