bmw -homebrew oil fill

[Russell]

4 quarts 5w50 Castrol Syntec and 2 quarts of 10w 40 Castrol Syntec in my 95 bmw 525i with 138,000 miles. brew should raise the lower viscosity a bit while the upper will be plenty high enough.

I think I am through with the 0-whatever in older cars. They have enough wear that lower viscosity oil is just not good.

I am going to send my 0w30 Castrol Syntec (aka GC-German Castrol) off for a Used Oil Analyis. I bet it has higher metals that desired.

 

[Thatwouldbegreat]

I'd like to see that UOA.

 

[Russell]

When I get the UOA back, which I will send in a few day, I will post a results summary in the oil analysis section.

 

[Craig in Canada]

Quote:

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I think I am through with the 0-whatever in older cars. They have enough wear that lower viscosity oil is just not good.

I am going to send my 0w30 Castrol Syntec (aka GC-German Castrol) off for a Used Oil Analyis. I bet it has higher metals that desired.

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That seems like a silly statement. GC is practically a 40, yet you lump it in with 0W-"whatever" and summarize that they're all too thin for anything "old". There could very easily be 10W40s that are just as "thin".

I believe most of the reasons people want to go thick in older cars is noise, poor compression, and oil consumption. I'm not so sure that any of those things would translate to higher metals unless fuel dilution due to poor compression caused wear that had nothing to do with the viscosity of the oil itself.

 

[Russell]

I had several poor uaos with mobil 1 0w40. Had high lead and fuel dilution issues. Keep in mind, the BMW M50 engine is known as a fuel diluter on the best of days. BTW, the 0w30 I took out did not smell of gasoline. Even so, it was very dark drown.

last year I ran two Auto-RX treatments to clean ring pack etc.. Never had a oil consumption issue. BTW, factory compression is about 10 to 1 with knock sensors. Had a cold start up lifter noise issue with 10 weight and above in cold weather, not warm weather. Can runs fine (summer/winter) on 5w40 and 5w50. Yes I want a quieter running car. This is one reason i did not like Mobil 1 0w40.

I tried thinner and think it is damaging my engine. At best it appears to be of no benefit. Dealer and Indy all recommend 10 weight and higher in older BMWs. Someone please tell me why?

 

[Craig in Canada]

A couple points in response:

You likely had a poor UOA on M1 0W40 because of fuel dilution. The oil didn't cause the fuel dilution but the fuel dilution caused the high lead. Do you have any sticky injectors? Do your engine temperature sensors work perfectly (the one(s) that control mixture not run the temperature gauge)? O2 sensors changed within an appropriate amount of time? If you can fix your fuel dilution and you'll go further towards lower wear than tinkering with oil. If you can't fix it, you simply need to change it very often. Maybe a 5W30 dino is more your speed?

Second, M1 is known in many engines to make them noisy regardless of the viscosity. My 1998 M52 was FAR noisier on M1 0W40 than anything else. My UOA on M1 0W40 was excellent despite this (it's in the UOA forum) although it sheared down to a 30. My other vehicles also had the same kind of noise ramp up over the years as M1 changed their formula - they were running 5W30 and 15W50 varieties. On the other hand, lots of people seem to notice no difference in engine noise with M1. I don't think anyone has figured it out yet. I'm running GC now and I'm extremely happy.

I responded to rebut your assertion that the "0W" part of the oil rating was contributing to higher wear. In your case you need to adjust the cold rating to get the startup noise performance you'd like (for which thinner seems to be better) and the full temperature grade for the protection, noise and fuel economy that you desire. I feel that your poor UOAs are strictly fuel dilution related. Nothing but fixing the car or frequent OCIs will ever help that. M1 0W40 has oodles of excellent UOAs posted - don't blame the oil or it's 0W rating. If you have excellent compression (measured, not the factory rating) and the engine is generally in great shape I don't think 50 weights are necessarily your answer. At least it doesn't get very cold where you are....

 

[Russell]

I sort of agree re the fuel dilution. I have the original injectors and the OX sensor has 80,000 miles (sensor may be getting lazy). Have no idea re the temp sensors (great idea to check). Perhaps fuel dilution is my problem. I get excellent mileage on the highway 29-31. city is lower than I would like, 14 to 17 mix.Even Lower in very heavy stop and go. Even so I DO NOT WANT TO GO TO 5W30 DINO!! Why would I want to do that?

Anyway, thanks for your advice. It actually mirrors Terry Dyson's advice.

Been trying to work on any of the dilution issues as I think appropiate and cost effective. I am just about due for the Ox sensor replacement and just do not want/afford to put in new injectors. Instead I run Techron injector cleaner and use 93 octane gas. The car is E.A.T. performance chipped.

 

[Craig in Canada]

My 5W30 dino response was part of a 'change very often' recommendation. If you're unable to cure the dilution and frequent OCIs are your only choice, a strong dino 5W30 would be much more cost effective. (ie. GTX) I confused why you think a dino 5W30 would result in lower fuel economy than the xW40 and xW50 synthetics that you originally stated you wanted to run. At any rate, I wouldn't fear any API SM group III dino oil if you were changing frequently. That's all I meant. There's an UOA in the forum from Castrol GTX in a 90s 740 that was not a short OCI and the results were still excellent.

You wouldn't need to replace your injectors. There are shops that rebuild them for quite reasonable rates. I've done it on previous vehicles, even where I regularly used cleaners like Techron or Redline, and it still made quite a difference. If you have a failed O-ring or something like that Techron isn't going to fix it. The rebuilder will generally send you back a sheet with flow rate and spray pattern results before and after. I can't remember the cost per injector but it was a no-brainer if you have a second vehicle to use to drop them off and can afford a day of downtime. They will replace all of the O-rings, clean with solvent, and replace the on-injector filter which clogs up over time. You'd also find out if you had one leaking down after engine shutdown and putting fuel into your oil.

My 1998 M52 is Dinan stage 3 chipped. I'm running RL MTL in the transmission, RL 75W90 in the rear end, GC in the engine, FP60 in the fuel. I'm used to obsessing over my cars but as it ages "cost effective" is becoming a personal struggle to start to let things go

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I'd look into the temp sensors, actually. You might find something there. If you have access to service information it might contain a test (voltage/resistance reading of X for temperature Y) that you could use to test it. Make sure you're not using the gauge, or the cooling fan sensor, but the ECU mixture one. Not sure if you're OBD2 or OBD1 in 1995 but a scantool might be able to read the sensor input and fuel trims as well. I haven't wrenched on an M50TU (yet)

Cheers.

 

[Ken E.]

Your attempt at fine-tuning your motor oil seems...well, kinda pointless. You have no idea what you really end up with, just what you suppose should happen. Why would you not just use one of the synthetic 15w-40 motor oils out there and be done with it? Or better yet, Rotella 5w-40? The BMW engine will still go 250k miles without obsessive/compulsive oil mixing.

 

[Russell]

Ken, IMO, wrong. This engine, perhaps all older M50 engines has a cold start rattle with 10 weight and above in cold weather. I can run any sort of heavier oil in the summer. In fact I have used 15w40 oils with sucess. However, they rattle like mad for the first minute upon a cold start in the winter. My experience with German Castrol 0w30 and Mobil 1 0w40 seem to indicate that lighter weight oils impact a warm idle clicking which is solved by perhap at least a 5 weight oil. Perhaps it is obsesive to "fine tune" oil. But so what?

Look what forum we are on!

Craig, I am going to recheck my options for cleaning/rebuilding my injectors. My indy told me they sent them out and it would take a few days to get them returned. Perhaps there is someone locally that can do it quicker. I need the car every day and My wife needs her car every day. Another good idea thanks.

 

[Stanley Rockafeller]

Stick with a 5w oil. I have done so in my m20, and it's much better than the 15e that was in there when I bought the car.

I also find that the Esso XDW 0w40 is too thin, and there was too much valvetrain noise when the engine and oil was cold.

IMHO, with today's advanced oils, there's no need for an oil that's any thicker than a 10w for the older BMW's

 

[Ken E.]

[q
IMHO, with today's advanced oils, there's no need for an oil that's any thicker than a 10w for the older BMW's

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My point. Why not just use 5w-40 or 5w-50 year around rather than try to re-invent the wheel? I have 5w/40 Pentosin in my 1981 M90B35 Euro engine. I'm confident it'll be just fine.

 

[Russell]

OK Ok!5w40 or 5w50 on my next fill. This was my conclusion anyway as it has worked well in the past. Now for the best OTC 5wxx oil.