Author Topic: automatic fluid consumption  (Read 1612 times)

Tomi

  • Classic
  • **
  • Posts: 180
  • Location: Finland
automatic fluid consumption
« on: 18 July 2006, 10:34 AM »
hello fellows,

back from holidays and have been driving the 116 for about 3000 km now. Some issues have come up and the primary one is automatic fluid consumption. My car seems to use 0,8 litres per 1000 km of auto fluid. This is not an economic issue, just something to be aware after long drives and I dont like it.  It does not leave any marks on the ground, so it has to disappear during driving. The torque converter area is a little wet, but nothing special (just like my SL which does not consume at all). Otherwise no signs of leaking.
I cannot figure out where the fluid goes. Is it possible that it goes up thru the gearbox vacuum line towards the engine ?
what is your auto fluid consumption ?

regards, Tomi
« Last Edit: 18 July 2006, 11:40 AM by Tomi »
MB 450 SEL -80 (oldtimer for the class)
MB E220T -95 (daily driver)
MB 230E -82 (a present for my son)

oscar

  • W116 Addict
  • ****
  • Posts: 4,043
  • Location: Riverina, NSW, AUSTRALIA
Re: automatic fluid consumption
« Reply #1 on: 18 July 2006, 03:57 PM »
Hi Tomi,

Did you notice any smoke?  During my holidays I had my car up a hoist and found the line after the vacuum modulator was wet inside with oil.   Like yours, the area around the torque converter is moist but doesn't drop oil.  I'd change the modulator in mine straight away if I could.  The problem is my mechanic is 2 hours away and without a hoist I can't fit my fat head underneath the car.  So I use oil but it's at a slow rate and I don't do enough mileage to get an accurate reading. (My dipstick's also broken at the tip) >:(

Regarding smoke, I get some blue at the moment which has only just reappeared but when I accelerate and force a kick down I think there's a puff of white.  Also, I've read it's recommended to flush that vacuum line to remove traces of oil after the modulator's changed.  Don't know how or what with.  I don't even know where the line goes into the manifold.  Good luck.
1973 350SE, my first & fave

s class

  • W116 Addict
  • ****
  • Posts: 4,171
  • I'll keep the 116's, the rest can go
  • Location: Squeezing 3 W116's into a double garage
Re: automatic fluid consumption
« Reply #2 on: 19 July 2006, 02:01 AM »
I agree with the posts by the others - the seal between the torque converter and engine is a common problem, as is the modulator valve.  I suspect that in your case it may be a bit of both.  In my experience, the modulator valve can be leaking a bit, and yet the shifting isn't too bad. 

Of the 2 possibilities, the modulator valve is the easiest to check and replace, so I'd start there.  There are two types - the earlier metal top ones have a banjo fitting (if I remember correctly).  Open this fitting, if there's ATF inside, your modulator valve is kaput.  On the later plastic top valves, there is a plastic nipple that is attached to standard MB vacuum hose with a rubber joiner piece.  Open this and again look for ATF. 

Big Richard, I think now there is a third possibility.  In addition to the radial oil seal, the front seal around the gearbox oil pump in the bellhousing can also be brittle and leak.  Again, that would only be an issue when driving. 

So Tomi, check the modulator.  If you then decide you must replace the radial oil seal on the gearbox, while you're at it replace both the inner and outer seals on the pump.  They're not expensive. 

Oh, Tomi have you checked the seal at the back of the gearbox where the prop shaft comes out?  I've also seen them leak there.

Ryan

'76 6.9 Euro, '78 6.9 AMG, '80 280SE, '74 350SE, '82 500SEL euro full hydro, '83 500SEL euro full hydro , '81 500SL

Tomi

  • Classic
  • **
  • Posts: 180
  • Location: Finland
Re: automatic fluid consumption
« Reply #3 on: 19 July 2006, 09:45 AM »
thanks for the tips,

I opened the vacuum modulator cap and it was filled with fluid. So I went to the dealer and got a new modulator (69 euros). It did smooth the gearbox, boy that change from 1 to 2 is wonderful now  ;D. I hope this has an effect on fluid consumption as well, but that remains to be seen.
The oil seal may still be the problem but Im not taking the box down for this. The fluid consumption should be much higher for this major task.

Now I have to adjust the parking brake as it doesnt hold in steep slopes, I guess it is thru the hole in the back wheel screw.

regards, Tomi
MB 450 SEL -80 (oldtimer for the class)
MB E220T -95 (daily driver)
MB 230E -82 (a present for my son)