frankvan

Is it possible to remove the oil return tubes with the engine intact through the exhaust valve head?
I think my major oil leak is the return tube seal at the head end. I removed the valve cover (did valve adjustment while in there!) and snap ring on the crankcase side but the tube still don't move

TIA

Frank

dfinnegan

Generally speaking the oil return tube is installed with the engine apart.

However, Expandable Oil Return Tubes are available to allow for replacement without breaking down the engine.

frankvan

http://www.pelicanparts.com/techarti...eturn_tube.htm

Looks like i have to twist and turn and push in from the head to remove?. Definitely do-able with engine intact but might have to remove H/E to get at it.

What's interesting is that my circlip groove is about 2 mm from the crankcase end, whereas the two piece units on Pelican look like the circlip is in the middle of the tube.

dfinnegan

My understanding is that the return tubes are supposed to be solid one piece units, but that replacing the one piece units requires removing the heads. To get around that problem the two piece units were made available. These can be installed without removing the heads and have the circlip to keep them fully extended once in place.

If you have circlips now, I expect you have after market two piece units.

bb964

When my car was under warranty I had one of these two piece units installed by the dealer, therefore I believe it is a Porsche approved solution

Duck

I have replaced all mine with the expandable type. The hardest part for me was taking off the heat exchangers. The replacement of the tubes was fairly easy. I just crushed them with vice grips and was able to twist them out. They are not very strong.

Putting in the expandable ones is tricky to spread them, but I put a hose clamp on the smaller end to give something to press against. There should be several writes on how to do this.

frankvan

I don't don't know what type mine are - they don't look like any of the tubes on Pelican (one or two piece). When I get one of them out I'll take a picture of it. It almost looks like a three piece unit from what I can see so far. I can get them off without removing heads but do need to remove exhaust. Just need to source a deep offset 12mm wrench locally....

dfinnegan

I think the exhaust bolts are a combination of 13mm and allen; (8) and (4) iirc

A thin walled, 6-point, swivel head 13mm is recommended.

frankvan

Got the manifold off. Nuts: 10x 12mm and 2x 13mm. I think the 13mm nuts were from when the engine had it's "factory" rebuild back in the early 90's for the head "gasket" issue and the mechanic probably lost two of the 12mm's!? (they're the same thread as the 12's).

The oil return tubes appear to be 3 piece aluminium. I'll post a pic to show what I mean! (just gotta get the camera from the wife). They come out without removing heads. The outer (head end) red seal is definitely knackered.

FWIW, I ordered a seal kit from autopartsway for $5 that comes with 2 red seals, 3 thin black O-rings, and a new circlip. Local dealer wanted $5 for each red seal and would have to special order them.

frankvan
89 C4

dfinnegan

Interesting. I have several (I think 4) barrel nuts that are allen keyed and then, I think, the rest are all 13mm.

I wonder why there is a variance?

frankvan

Pretty sure the 4 nuts you access through the holes in the heat exchangers have to be 12 - my 12mm socket barely fit through the holes (i actually dremelled the lip on one of them so that it would fit). Can't see how you could get a 13mm socket up through the hole. (unless we're talking about something different).

Seals should be arriving via UPS today.

dfinnegan

That's just where my four allen nuts are. Up through the heat exchanger.

Checkout Jason's Post #6.

crg53

When I took off my HE's there were 4 allen nuts and 8 hex nuts. 3 of those hex nuts were 13m/m regular nuts and 5 were 12m/m copperized flange nuts. Now all 8 hex nuts are 13m/m copperized flange nuts. Sometimes it just depends on the skill & attitude of the last mechanic who was in there.

frankvan

Pictures!
I think the "third" piece (red seal piece on right) of my oil return tube is not supposed to come off as there is no rubber o-ring to seal underneath it. The same piece on the other side (with two o-rings) is actually a slightly different diameter and won't fit on the other end of the oil tube.
I think a little gasket sealer for the non-sealed flange may be in order when re-installing.

as to the nut question, mine is an 89, maybe they changed to the allen style and 13mm later on? none of my nuts are flanged, but there are washers for each one (it'll be fun trying to balance those back onto the studs)

John D.

Ummm... Wow??? I have never seen that design? I just installed two-piece returns - one in my 993 engine, and have used them previously in Jen's 964 (but went with one-piece as I finished up her engine this week)... Anyway... Here are three potential issues I see straight away on that design:

On a two piece tube - the smaller OD pipe *always* goes into the head - as oil flows from from the head into the case (from a smaller OD into a larger OD). On this design, you are totally dependent on the inner seals to block against seepage..?? Hmmm....

Installation... The circlip position will demand you remove the header/exchanger, as the inner seals will have to be on the head side (see my point above)?

Movement.. With one circlip only - what's to prevent the main tube moving into the case (and there are no seals/circlips at that end?)...

Anyway - just my opinion - but I'd go with a two-piece design...

On installation - LUBE THE large O-Rings!!!

As well - the washers will stay on the nuts - just put a dab of grease on the washer before placing them on top of the nuts and running them up through the exchangers...

John