M30 engine oil leaks

[Rus]

Hey everyone,

Here's a question to the M30 gurus out there. I am experiencing the famous oil leak from the front of the engine. The upper CPS mount bolt is to blame. In the past, I have applied sealant to the shaft of the bolt (not the threads) and the leak subsided. Recently, I disturbed the bolt while changing the CPS and it has begun to leak again. On the web there are two recommendations that are given. 1) Take out the bolt, clean it, apply threadlock and reinstall. 2) Remove the bolt, clean it and seal the threads. I have both threadlocking compound and thread sealant, but can't decide which to go with. Do the threads of the upper mount bolt actually penetrate into the oiled area? Would it be more appropriate to use a thread sealant there instead of plain threadlock? Should I apply any sealant to the shank of the bolt and under the head? I would really appreciate some input from those who've successfully fixed this pesky leak.

Also, I have a little oil coming up around the oil dipstick guide tube. I know there has got to be an o-ring at the base and its probably all cracked now. RealOEM does not show an o-ring on any part diagrams that I can locate. Is there an o-ring there? If so, does anyone have a part number for it?

Thanks in advance!

[Bill R.]

There is no oring seal on the dipstick tube, they use loctite as mentioned above. Use thread sealer not thread locker on the timing cover bolt. Loctite makes one that works well.

Hey everyone,

Here's a question to the M30 gurus out there. I am experiencing the famous oil leak from the front of the engine. The upper CPS mount bolt is to blame. In the past, I have applied sealant to the shaft of the bolt (not the threads) and the leak subsided. Recently, I disturbed the bolt while changing the CPS and it has begun to leak again. On the web there are two recommendations that are given. 1) Take out the bolt, clean it, apply threadlock and reinstall. 2) Remove the bolt, clean it and seal the threads. I have both threadlocking compound and thread sealant, but can't decide which to go with. Do the threads of the upper mount bolt actually penetrate into the oiled area? Would it be more appropriate to use a thread sealant there instead of plain threadlock? Should I apply any sealant to the shank of the bolt and under the head? I would really appreciate some input from those who've successfully fixed this pesky leak.

Also, I have a little oil coming up around the oil dipstick guide tube. I know there has got to be an o-ring at the base and its probably all cracked now. RealOEM does not show an o-ring on any part diagrams that I can locate. Is there an o-ring there? If so, does anyone have a part number for it?

Thanks in advance!

[Rus]

Bill,

Permatex lists four thread sealing compounds here: http://www.permatex.com/products/Aut...d_sealants.htm

I have the high temperature one. I put a little on an index card to see how it cures and almost 6 hours later it is still very liquid. How is thread sealant supposed to behave? From the four listed, which one would you recommend for this application?

And thank you for clarifying the dipstick tube confusion. I guess I'll have to pull it out and reseat it with new locktite.

[gale]

I've had very good luck with Permatex "Ultra Copper" on hot oil gasketed joints. I smeared a liberal amount on the CPS bolt threads, shank, and under the head and no leaks. I cleaned everything with alcohol and then acetone beforehand.

http://www.permatex.com/products/Aut...sket_Maker.htm

[Bill R.]

Bill,

Permatex lists four thread sealing compounds here: http://www.permatex.com/products/Aut...d_sealants.htm

I have the high temperature one. I put a little on an index card to see how it cures and almost 6 hours later it is still very liquid. How is thread sealant supposed to behave? From the four listed, which one would you recommend for this application?

And thank you for clarifying the dipstick tube confusion. I guess I'll have to pull it out and reseat it with new locktite.

Rus, I think that the permatex sealer you have will work fine and i also think its typical of loctite products in that it won't cure except in the absence of air, they list a 4 hour workable time for it after assy.

I like hylomar for threaded joints also and its wierdly enough available at my local harbor freight for a really cheap price.... I used to be able to get it at autozone and then they stopped carrying it. Then the only place i could get it was at the races and it was the original hylomar brand, megabucks not like the permatex brand hylomar which is priced reasonably.

[Rus]

Hey guys,

Update: I tried just tightening up the upper bracket bolt yesterday. It was pretty loose. I cleaned up the oil from the bottom of the engine and drove the car for a bit running errands. After checking it today, there's oil on the pan again, but no oil coming from the upper bracket bolt. In fact, there's really no oily mess above the lower bracket bolt. This site suggests that its possible to get at the lower bolt with a spanner. Is this true? From the looks of it, the A/C compressor will be in the way, but I have some stubby wrenches I could use. Any feedback is appreciated as I try to track down this leak.

Edit:
Update #2 - I jacked the car up and climbed underneath to see if I could reach the lower CPS bolt. Then I remembered Winfred mentioning that M30 engines occasionally need their oil sump bolts tightened up. I checked mine and sure enough, all the front bolts were finger-tight if not more loose. I went around the pan and cinched up all the bolts. Now its a waiting game to see if that will fix the leak.

[93 525 Paul]

...any chance you have similarly insightful info on the M50?
(end hijack.)
Thanks in advance.
Paul

[Rus]

Paul,

My brother recently tackled an oil leaks on his M50. Specifically the oil filter housing oil leaks. Where is your leak originating? Just thought I'd throw this out there.

[russiankid]

...any chance you have similarly insightful info on the M50?
(end hijack.)
Thanks in advance.
Paul

Check out this thread, may be your problem.

http://forums.bimmerforums.com/forum....php?t=1109419

[Rus]

Update #3: The oil leak persists largely unchanged. Next up is going to be the CPS mount bolt since I didn't seal it up when I torqued down the oil pan.

Edit:
Update #4: Removed the upper CPS mount bolt and cleaned it up. The lower mount bolt can be reached with a stubby 10 mm spanner. To do so, the 10 mm nut holding the CPS adjuster in place needs to be removed. The adjuster with the CPS mounted to it slides out and you gain the space necessary to reach the lower bolt. Mine was a bit loose, but didn't take much to tighten up. Will report again once I drive the car and check for leaks.