View Full Version : urgent question

04-07-2004, 03:31 PM
I've been having a problem for years with losing oil from the gearbox
(transmission) on my e30 track car. I replaced one seal after another and
eventually came to the conclusion that it must be one of the seals in the
front that you can't get to without opening the box up. So last January I
bought a used gearbox from another club racer and it loses oil too, maybe
worse than my original box. Since the replacement doesn't hold oil either
I took the original box into a shop and asked them to replace the front
seals that are only accessible from inside. They called a little while
ago and said there is nothing wrong with those seals. They suggested that
maybe I am losing the oil out of the breather vent. Does this sound
plausable to anyone else? I can't tell exactly where the oil comes from
does it does seem to be primarily all down the drivers side of the car,
and sometimes I notice it dripping off of the slave cylinder too.



04-07-2004, 04:08 PM
I raced an e-30 from '90 'till '95 and it would blow oil out of the breather. What i did was to remove the stock breather and carefully tap out the hole to a pipe thread, sorry I dont remember what size. Then I screwed in a 45 degree Aeroquip type fitting that had a pipe thread on one end and a regular fitting that I could slip a hose about two feet long on to the other end. I just ty strapped that hose straight up to the firewall. And that took care of the problem.
You can call me at 310-962-0607 if you want.

04-07-2004, 04:32 PM
BMW RACER is correct. You don't need to go to the extreme of tapping the hole, etc... All you need to do is pry the plastic cap off of the breather. Then take an old coolant hose (one of the hoses that connect to the throttle body works great) and connect it to the breather. The throttle body hose is perfect because it has a 180 degree bend that allows the hose to hang down the side of the tranny.

04-08-2004, 10:41 AM
Thanks guys. I'll try to rig something up to keep the oil off the track before my next race.

I shoulda asked about this YEARS ago. I've been fighting this problem for a long time.


04-08-2004, 12:39 PM
doh! i should have thought of that while i was mopping up the oil on the bottom of your car and refilling the tranny!

my yellow e30 had some clear vinyl tubing stuck on the breather tube. it ran up into the engine compt and into a modified plastic welches grape jelly jar. car never dripped tranny oil. actually, the hose was long enough and rie tall enough that the oil never reached the catch bottle, just drained back into the tranny.

technically you can't (and shouldn't) just use a 180 hose and "redirect" the overflow. that dumps oil on the track, not cool. you have to route it to a catch bottle.


04-08-2004, 04:33 PM

not one drop of oil comes out of mine. The hose goes 2" straight up and then the 180 down the side of the tranny. It's not like there is pressure inside the tranny squirting oil thru the breather. The extra high revs of racing just throws the oil around more and it hits the top of the breather and drips out. The end of my hose is right above the slave cylinder, and if any oil came out of the hose there would be oil on the slave cylinder.

04-11-2004, 01:28 PM
i said you shouldn't because if oil DOES come out it ends up on the track. i also though this was an scca rule, but the catch tank rule only applies to engine breathers.

if yours doesn't drip oil that you know of, good for you. yes, it should be low volume/low probability, but i just prefer to eliminate the potential that i may be leaving something on the track that i or a fellow racer may slip in. cheap, easy prevention of on track incidents.


04-12-2004, 08:02 AM
No dump tank for tranny vents???

Please Read 17.26 and 11.2.1.T of the GCR.

Do not think that all our rules are in the ITCS.


04-12-2004, 04:31 PM
I just came in from the garage after re-routing my hose into the engine oil catch tank. I took all of 3 minutes to do.

04-20-2004, 11:05 AM
Thanks to all who replied!

I rigged up a vent hose and catch-tank (1/2" heater hose and 20oz plastic pepsi bottle) and it didn't blow a bit of oil over a 3 day race weekend.

I did have a bit of a scare after the first practice session when I looked under the car and saw something dripping off the bottom. Turned out that I left the radiator cap a little loose and I blew a little coolant out. Now I have a catch tank for my radiator overflow too -- another 20oz pepsi bottle http://Forum.ImprovedTouring.com/it/smile.gif


04-21-2004, 01:43 PM
thanks for the rule quote joel. i didn't look hard enough.

glad your car is "clean" now!