GC in BMW M42

Messages
177
Location
Salem,Oregon
Just dropped out the Auto RX rinse cycle from my BMW 318iS and put in Castrol 0w-30. I know the BMW purists will balk at the use of 30 weight in this engine, but from a purely subjective view the engine noise has lessened noticeably at startup. BITOG has had it's way with me: GC in the 318 and Pentosynth 5w-40 in the E30 325.
 
Messages
144
Location
Ohio
I too have a 318is and I am quite familiar with the M42 (and BMWs in general). The only issue I see is that the M42 is a sieve and leaks more than any motor I know of due to one of the more convoluted headgasket/profile gasket/timing gasket/timing cover gaskets/etc. designs I am aware of. For that matter, these motors were known to leak in as little as two years (aside from the profile gasket) after being produced as BMW dealers can attest to. I recently freshened up an M42 in my car (all new gaskets) and its very first fill was sacrificial BMW Castrol Synthetic and quickly followed with a fill of GC Green. Here are some pics of it (I did some powdercoating of the valve cover/oil pan/timing cover/intake/etc.: www.rdgarage.com/m42motor1s.jpg www.rdgarage.com/m42motor2s.jpg www.rdgarage.com/m42motor3s.jpg Guess what? It leaked, a lot. I have to figure out where and why? I really don't want to be leaving oil spots everywhere I park and I really do want to run GC in this vehicle as it is my daily driver and sees a lot of miles. After replacing the brake lines recently, it appears the oil pan(s) bolts were a bit loose and may have been contributing to the leaking, we will see, that would be too simple of an answer. Otherwise, it is a very fun motor, likes to rev and pulls very well in this car. It really was a great motor for its time, just a very convoluted design. It should run fine using the GC in my opinion. Good luck. Regards, Rich '95 M3 '90 325is '91 318is
 

Ken E.

Thread starter
Messages
177
Location
Salem,Oregon
Nice pics Rich. Mine leaks also but since it leaks with dino I figured what the heck, it might as well drip fancy German synthetic on my driveway instead. More class. I wll crawl under it and check the pan bolts however, thanks. Ken
 
Messages
6,336
Location
KY
I guess I must be living right. My 101K M42 is still pretty tight-no drips, just a very slight seepage around the lower timing chain cover. I tried BMW's 5W-40 and 5W-30 synthetic but the rest of the time I've run M1 15W-50 and changed it according to the SI lights. That said, I am considering a switch to M1 0W-40.
 

JHZR2

Staff member
Messages
46,143
Location
New Jersey
my 103k m42 loves rotella syn 5w-40, but ive always been tempted to use gc or a similar heavy 30wt. jmh
 

jaj

Messages
1,060
Location
Vancouver, Canada
I used to have a 1992 318is with the M42 1.8 liter engine. The miracle of the 4-valve M42 is that the HP per liter is essentially the same as the 400HP MY2000 to 2003 M5 S62 engine - 80HP per litre. I have to say that the extra 3.2 liters in the S62 really transforms the driving experience... Cheers JJ
 
Messages
144
Location
Ohio
They all leak. MCompact is living right if he only has seepage, I would be happy with just seepage. My oil pan bolts were loose as I had only tightened them to BMW spec when I reassembled the motor. Once the 318is was run for 5,000 miles after reinstalling the motor, it was clear to me that the oil pan bolts weren't snug and so I snugged them up some. I wasn't implying that yours would also leak from the same area. Actually, they most frequently leak from the timing covers (top or bottom) either from the gaskets between the cover and the block or between the covers. They leak elsewhere too. I need to put it back on my lift again and clean the underside some and again start looking for where any leaks may be coming from to see if they are easily addressed. Most of the exercise in pulling the motor and freshening up the spare motor I had with all new gaskets from top to bottom was to stop oil leakage... :-( Regards, Rich
 
Messages
846
Location
Under the hood
My 13-year old 101k M42 has never put a drop of oil on the ground. I guess I must be living right, too. It got 20-50 GTX early in its life, then M1 15-50 up until the switch to M1 EP; since then I've been using M1 0-40. The profile gasket went at 65k. I've replaced the VC gaskets for the typical oil in plug tube problem that M50/52s also have. The only fluid that's ever tainted my garage floor came from a bad differential input seal, and that was minor enough for the mechanic to recommend I hold off, but I didn't like the idea of any drips whatsover.
 
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