Blowing oil out of the dipstick tube seal

[fspGTD]

I have a problem recently when I race (when I take the engine up to high RPMs wide open) I get oil leaked out from where the dipstick housing tube installs into the block.  This is on a 1.6lTD engine code CY, from an '84 Jetta.  Now I can't remember exactly what I've got in there sealing it, but it looks like it might just be some sort of felt doughnut/washer.  IE: not a very positive seal.  The first time I was most hard on it that it leaked, it lifted the felt seal up out of the recess in the block and left it hanging about a inch up on the dipstick tube housing.  Some oil came out.  Not enough to cause any engine troubles (oil level on the dipstick is fine) but it got all over the bottom of the oil pan and on some of the front suspension parts.  Then it dripped down onto the racetrack (which other racers don't appreciate  :oops: )

Now recently I was checking out another '84 Jetta TD and noticed it had a thick rubber o-ring, and on top of that a metal washer that would jam the o-ring down into the recess when the dipstick housing tube was installed in the block.  Is the rubber o-ring and metal washer the parts that the TD setup should have?

Another thought was since I am revving this engine up so high, maybe I should add the crankcase vent at the gas-engine-fuel-lift-pump block off plate.  Apparently the 1.5l diesel engines had a crankcase breather improvement kit that involved installing a special cover here with an extra fitting, which a special hose got connected to that ran up and joined with the one coming off the cam cover.  This kit was to prevent engine runaway (too much oil in crankcase vent).  I noticed a 1.9lTD had some sort of plastic looking vent tube as well.  What do you think would be the easiest way for me to improve the crankcase ventilation on my 1.6lTD?  I was thinking maybe get an 1/2" or 5/8" hose barbed to NPT 90 degree fitting and then just drilling and tapping the stock cover maybe...  then running some rubber hose up to cam cover area, tee'ing into the hose I've got coming off the crankcase vent up there (I think that hose is 5/8"ID.)

Here you can see my existing crankcase vent system (the hose just leads to atmosphere down below the engine compartment by the way)

[type53b_gtd]

Jake, it sounds like your crankcase vent mod is not allowing sufficient venting at high rpms for sure.  The small green o-ring and retaining washer are ifactory parts on the TD's - in fact, all later disels. However, if crankcase pressure is sufficient, it will spit oil out the top of the tube instead of the bottom (ask me how I know...)

I would reccommend a larger diameter hose off the head (if you've added length without increasing diameter this will increase pressure in the hose)  and a vent on the block.  For a while I ran one from an early 1.6 NA that had the old style vaccum pump that actually teed into the blockoff plate on the side of the block (the part number is 068 193 111, and it allows for about a half inch hose connection, so don't take it too far unless you increase the diameter.)  You should find the old style vaccum pump on 1.5's and early 1.6's I think.

However, I now run a 1.9 AAZ crankcase vent pipe up to a 1.9 pressure valve on the head - this works much better.  The 1.9 adapter plate bolts right on where the blockoff plate is on the 1.6.  I installed some stainless scouring pad material in the 1.9 vent pipe (which is molded plastic) to help catch oil vapour.

I got my parts from a spare block, but what you need is shown in this screenshot:

http://scirocco.cs.uoguelph.ca/gtd/misc/aaz_ccv.jpg

HTH- Drew

[DieselsRcool]

Jake
I have a few spare block off plates with either 1 or 2 hose barbs. I think you need the 1barb plate as I think you are running the newer vac pump without vent hose. Email me your address and I'll drop one in the mail for ya.
Larry

[fspGTD]

Thanks Larry!  IM sent.  

Also thanks for the info on the dipstick tube seals Drew - it looks like I've got the wrong felt-type seal in there.  I just ordered what I hope to be the rubber o-ring the slim metal washer seal setup from the dealer, price was under $5 (part number were N 015 401 3, and 076 115 643)  Hopefully I won't just get another crappy felt washer when the parts come in though.  :?  Thanks again guys!

[fspGTD]

Looking at where my car was dripping the oil, right after the couse traveling slowly back to grid, I think it could have been the heavy braking after going through the finish lights (probably > 1G braking force on my race rubber) that could make the oil level inside the oil pan climb up the front side of it and leak out through the bad dipstick tube to block seal.  After it leaks out of that location, it gets all over the block and then drips down onto the track afterwards.  In this case, the problem might not have much to do with positive crankcase pressure even.  But I'm going to tackle this problem aggressively - crankcase vent system improvements as well as install the o-ring seal where the dipstick tube goes into the engine block.  I want a good crankcase vent system as I may be revving my engine out even higher once I get that timing advance mod done.  :twisted:

[type53b_gtd]

Looking at where my car was dripping the oil, right after the couse traveling slowly back to grid, I think it could have been the heavy braking after going through the finish lights (probably > 1G braking force on my race rubber) that could make the oil level inside the oil pan climb up the front side of it and leak out through the bad dipstick tube to block seal.  After it leaks out of that location, it gets all over the block and then drips down onto the track afterwards.

The dipstick tube seal will leak easily if the crankcase is overfilled, so you may have something there Jake.  However, I thought you were running a baffled oil pan gasket (ie. windage tray?)  This would certainly reduce the likeliehood of the oil all piling up at the front of the engine.

Short bursts of high crankcase pressure will spit oil right out of the top of the dipstick though, so don't rule that one out yet...

Drew

[fspGTD]

I always keep my oil level near min (as running it at max seems to noticeably sap some power, I've found).  Although since starting to have the oil loss problem I've been running it more towards halfway between min and max, to add a little safety cushion.  True I do have the windage tray.

[fspGTD]

OK well, I pulled my dipstick tube out of the block today, and I think I found why the dipstick tube seal was leaking - green o-ring was there but had a crack in it, and also the dipstick tube where the o-ring had to seal against was severely chafed.  It must have been vibrating against something for the metal to chafe so severely like that (maybe the washer?)  So anyway, I installed a new green o-ring and an extra washer I bought (in addition to the old washer, which looked good) to space the o-ring down a little bit into a smoother area on the dipstick tube (less chafed.)  Hopefully that will work.  If it doesn't I think I'll need a new dipstick tube.

I'm also planning on installing a lower crankcase vent (thanks to LarryB for sending me the OEM lower crankcase vent pieces!  At this point I'm just trying to track down the other bits and pieces necessary to install it, hopefully will get those figured out soon!)

[fspGTD]

With DieselsRcool's help providing lower crankcase blockoff plate with vent nipple (thanks Larry!! ), I was able to piece together and install an extra crankcase breather coming off the block:



The ID of the hose coming off the block breather is 1/2".  The hose coming off the head is 5/8".  Hopefully this should do the trick to keep the oil in the crankcase where it belongs, combined with the new dipstick tube o-ring.  I can't wait to try it out at the autocross tomorrow.  

I may soon be running out of excuses of why not to experiment with increasing the revv-limiter beyond 6000 RPM.  

[Dr. Diesel]

my tach goes off the clock on auto-x straights where there isn't quite enough room for 3rd gear, but too much room for 2nd. (can't wait for the peloquin'd long ratio coming up... damned close ratio!) I've been loosing a little engine blood in the dipstick tube area too. I think I'll goober a bead of silicon around it's base on my new engine. A vw mechanic said bend the brace bracket such that when installed, it jams the tube harder against the block.

[fspGTD]

It seemed to work OK at the autocross today.  No more puking out out of the dipstick tube to engine block seal.  There is however a drip of oil out of the blowby outlet every so often, seemed like a little more than before.  I'm wondering if the vapors coming out of the crank might be more full of oil droplets, since they don't go through a baffle or anything.  I think I might try next what Drew did and stick some steel wool in the tube.  I could also add a catch-can but would rather not if I don't need to.  Drew, is there a specific grade of steel wool I should use?  I'm thinking maybe the course stuff?

[type53b_gtd]

I used stainless scouring pads from a local department store - 5 for a buck or something like that.  They're like stainless spirals, and do not fall apart like steel wool does (I was worried about steel wool falling back into the crankcase.)

I was able to jam one or two into the 1.9 vent tube, with some effort.

Drew

[DieselsRcool]

I have always used "Chore Boy" soft 100% copper scrub pads for this reason. Seems like a little piece of stainless or steel could do a lot of damage.

[fspGTD]

Larry - as recommended, I just picked up some "chore boy" copper pads for the Rabbit crankcase vent system.    Found them at Safeway!  So do you recommend I try stuffing a whole pad up into my crankcase vent tube?

[DieselsRcool]

I would think that might be a bit much. I wouldn't want to plug the tube and cause pressure build up. I'm not sure how you should do it without some sort of oil seperator.

On my old NA I just stuffed it into the breather baffle underside of the valve cover where there is room under the breather hose connection.

Sorry I'm not much real help.