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jim73vw
26-05-2009, 09:08 PM
Hi all,

Have been trying to trace a small oil leak on the engine for a while now. initially I thought it was rocker covers, and then seeping around the block.

Now I am not so sure.

I typically see 1 -2 drops after a long run, dropping from the lowest point at the rear under the pulley.

I dropped the engine today to get access to run ducting to the fan, and make my tinware extension to seal the engine bay.

I suspected the oil cooler seals, but in my experience if they go you know about it.

Here is the oil cooler exposed

http://farm4.static.flickr.com/3624/3567957112_66f770f52e_b.jpg

A bit of grime, but I don't beleive an oil leak if that clean ?

I did have a leak from the oil filler and the below shows what I beleive to be the residue from that

http://farm4.static.flickr.com/3350/3567956826_70361689f4_b.jpg

This is what I see behind the pulley and around the fuel pump etc

http://farm4.static.flickr.com/3319/3567956492_1fc779f16c_b.jpg

Even the pulley etc has a fine film on it. I am not losing a lot at all - not discernable on the dipstick, and what does drop appears clean.

Could it be seeping/spray behind the pulley under pressure?

Should I remove the oil cooler to be sure?

Any ideas ??

letterman7
26-05-2009, 10:29 PM
Well, Jim...either pulley has a seal to the engine block. Even a fine mist is telling you that one of the seals is compromised. If it's the front (crank) pulley, that seal is rather easy to replace. If it's the flywheel side, it's a little more involved, but still nothing too difficult. If it is the flywheel side, you do want to address that pretty soon, as the oil will soak the clutch pad and render it useless!

jimcub
26-05-2009, 11:02 PM
If that is the pulley side you may have a slight pressure in your case, that seal is a spiral that when spinning is suposed to drain any oil back to the engine. This is a principal that you find on steam glands normally, as a spriral spinning in the right direction is suposed to cause an inward pressure seal. if there is too much crank case pressure it will blow out through the least resistance, where do you vent your crank oil breather too ( is it blocked or too fine ) mine goes into the top of one air filter.

Spacenut
27-05-2009, 01:08 PM
That's a good point Jim - if it is an oil-thrower than a little bit of crankcase pressure can easily defeat the "seal". I did a job on a Morris Ital many moons ago that was losing 5 litres of oil a week due to this problem! The solution was to reconnect the crankcase breather pipe to the inlet manifold (it had been disconnected for some reason).

More recently the Barracuda was blowing a load of oil out of the dipstick tube for the same reason (collapsed breather hose).

Nena's got a new engine, so excess crankcase pressure is probably not the issue, but a check of the venting arrangements (PCV valves, breather pipes etc.) might help.

Good luck!

Lauren

jim73vw
27-05-2009, 01:55 PM
Cheers all,

I don't beleive it is the flywheel seal, as when they go they are more obvious, and having dropped the engine out last night that end seems clean.

The crankcase pressure seems the likely solution to me. Incidentally it seems to have been more of an issue since the deep sump was added - could that have changed the pressure?

I had been thinking about adding a breather box anyway, but shouldn't be necessary. Hoever I am not using the stock oil filler, which has a vent/weep pipe, so perhaps that is adding to the issue !?

Peter
27-05-2009, 03:18 PM
There isn't an oil seal on the pulley end of the crank just an oil thrower as stated but you can get an oil seal kit which fits behind the pulley as sold for sand rails to keep the sand out of the area rather than the oil in but it does both.

hildi25
27-05-2009, 06:47 PM
Usually if a VW motor isn't leaking oil that means to check it!

I would check the casing/oil pump bolts to make sure they are properly torqued. First then go from there.

Rob

Peter
28-05-2009, 01:50 PM
It's all in the quality and time taken in the re-build. mine doesn't leak, as you can see, and before anyone jumps in, yes it has been run. 80psi at about 85c,(60% on bar guage, that's the temp sender on the right) high pressure relief valve kit, every joint clean, flat and new gaskets and/or sealent and oil seals, a lot of AN fittings too. BUT, I am expecting a leak or three eventualy, as stated, if a VW engine doesn't show a bit of oil it probably doesn't have any!
http://img.photobucket.com/albums/v219/Ukhozi/rear/sumpheader.jpg

jim73vw
09-06-2009, 12:30 PM
Hi all,

I had a chat to Nigel at VW Heritage, the Remtec specialist re the engine and he also pointed to crankcase pressure.

As the engine is a mildly tuned 1641 it will need slighlty more breathing than stock, though a standard VW breather/oil filler should be sufficient.

However I don't have a standard system. I am using an aftermarket oil filler which has a smaller diameter breather pipe, which whilst to the Weber air filter, is a restricted flow. The right angle plastic connector to the air cleaner also constricts further, and reduces passage.

Rather than change the oil filler I added a breather box like Peter's, taking pipes from the oil filler and rocker covers. So far, so good, with it all looking clean and tidy :crossfinger:

Peter
09-06-2009, 06:50 PM
Well, sometimes I'm right and sometime people are wronge, just the way it is. :wink:
I hope to add the breather pipes from the box to the air filters this week too, so down the the hardware shope for some 1/2" braided water pipes.

Spacenut
10-06-2009, 12:34 PM
Any kind of performance camshaft will make more power by increasing valve lift and probably the overlap. The latter is the amount of time the inlet and exhaust valves are open simultaneously at the end of the exhaust stroke. The lumpier the cam, the less inlet manifold depression is created, which the PCV breather pipes are normally connected to. This in turn reduces the scavanging effect, particularly at small throttle openings.

In addition, higher compression pressure in the cylinders will cause more blow-by from the piston rings (they cannot provide a 100% seal), which has to be vented from the crankcase.

So its a double whammy. If your breather pipes merely attach to the air filter there may not be enough scavanging effect. Most PCV systems also connect a breather hose from the inlet manifold (at the base of the carburettor) to increase the positive venting, often with a PCV valve which is pressure sensitive, only responding when there is enough manifold depression present.

Things were even more loopy in the US as the emission laws started to bite - Exhaust Gas Recirculation (EGR) for starters :oops2:

Looking at your pictures I can't see that you have any cause for concern - I've got more fluid leaking from my throttle master cylinder (capacity 3cc) than you have from your engine!

Lauren

jim73vw
23-06-2009, 07:25 PM
Round trip to Newark and still clean and tidy, lovely :D