Flame suit on, its OK.
My 91 318i drips NO oil. It runs like a top and gets good MPGs. Never notice smoke unless I WOT in first gear to around 6000 RPM; WOT in any other gear, even at high RPM doesnt do it.
But it uses around a quart every 500-750 miles, and in cold weather it has a lifter tick at cold start until it pumps up.
I was interested to read about B-12 being used as an oil flush in the past, including some correspondence from someone in their company. http://www.bobistheoilguy.com/forums/ubbthreads.php/topics/2990606/1
In the past Ive tried Kreen, MMO, Ive run HDEOs, synthetics, conventionals, HM oils, etc. Nothing has helped. It seems to be less consumption around town, but I do drive the car at 3500 RPM on the highway at speed quite a bit.
So this was sort of a last-ditch effort. I had done the cleaners mentioned above, and since the last try, have probably gone through 5-10 quarts of oil. Ive tried LM MoS2 as an attempt to plug small gaps (if any existed) to reduce consumption. No dice.
So Im at the point where Ive gone down to an ILSAC GF-5, 5w-30 oil to reduce the ZDDP exposure of the catalyst to protect emissions since I live in a state where there are sniff tests every other year. The lifter I can live with, but wanted to try to see if I needed to risk pulling the cam (always a risk of damage/cracking) and replacing all lifters (at around $16 each for 16 of them), or leaving it, and to see if I wanted to even consider trying to tackle the consumption. Reality is that the car has some rust underneath, and we really need a minivan, so given our fleet of cars, this one is probably the one to sell if we were to sell one... So giving it to a kid who was interested in a project in a year or so was also in the cards.
Anyway, the sump is around 5.25 qt, so I added 8oz of B-12 into the sump, and then sucked around 2oz more down one of the vacuum lines. Idled the car for around 10 minutes until the heat came up.
I then drained the oil (mainly ST 5w-30 ILSAC CF-5), and replaced with some old SL and SM GTX 5w-30 that I had in the basement with no other use. I figured that the 5w-30 is OK in the winter and might help the lifters... it hadnt thus far.
I also figured Id be a bit more risky and tried some of the Restore CSL. Why? Why not. Yes, this is NOT a scientific test, and I dont have any compression numbers or anything else. Again, the car runs like a top, its just the comnsumption. So I added the dose for four cylinder cars.
We drove about 120 miles onver mountainous terrain in the car after the oil change. After that it sat out overnight in about 25 degree weather, which is generally sufficient to cause the lifter tick to occur, and also sometimes a tiny bit of timing chain slap at cold start.
We will know soon enough if there is a chance that consumption is reduced. Im fairly uneasy having that Restore CSL stuff in there, but I figured Id try something different... Lubro Moly motor oil saver and Ceratec were also on my list, but after MoS2 and that ATP-205 seal sweller both failed for me, I figured Id give the old fashioned stuff a try. The worst that can happen is that Im out a few bucks.
Again, this isnt a scientific test. No compression, no bore pics, no spark plugs. It was too cold and I dont have enough time. It was merely to see if I could help the lifter to pump up faster by cleaning it out (after everything else failed), and to see if I could slow consumption.
So thus far ive not heard any indication of a lifter tick, which is a good result. We will see if this stays the case, as it had gotten to the point where it would be notable after a workday at temperatures over freezing. Im OK with changing lifters, but it is about impossible to determine which it is. Engine was/is clean inside but I wanted to give it a try. Im OK with one or both products being snake oil. I was surprised to see a number of good reviews for the CSL on Amazon, which is what peaked my interest. Again, Im not that easy about having it in the engine, but for a short test, its OK. And if it reduces consumption like the claim, then I would be VERY happy. If consumption remains, I dont want those metals on the converter, so Ill be changing out early, but thats why I used the old GTX...
We will see. One test (cold start) is no test, time will tell. Ill report back.