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Leaking turbo oil inlet

 
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3forall  



Joined: 29 May 2015
Posts: 17
Location: Canada

PostPosted: Fri May 29, 2015 11:06 pm    Post subject: Leaking turbo oil inlet Reply with quote

The gasket between the oil inlet flange and the turbo is leaking quite badly and sending oil onto all the hot parts downwind from there making one heck of a smoke show. Although I like that it has taken care of tailgaters, I really should get it fixed.

The question is how to get to the gasket. The whole area is quite tight. As it is I see two potential ways. Either remove the charge tube and try to manage in the now slightly less tight space. The other way would be to remove the turbo.

Any opinions/suggestions would be welcome.
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1981 924 Weissach edition
1982 931 - Megasquirt and liquid intercooler
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Fasteddie313  



Joined: 29 Sep 2013
Posts: 2062
Location: MI

PostPosted: Sat May 30, 2015 4:24 am    Post subject: Reply with quote

If its a leak where the hard line connects to the mount you can snug it up, I think I cut a 19mm open end short for this.. (check size before you cut)

If its a leak between the mount and the turbo you can try tightening the 2 allen nuts with a bunch of extension, universal, and an allen driver. If you dont have an allen driver you could cut about an inch off of the correct size allen wrench and use it between a socket and the nut..

If that doesn't make it stop leaking and the leak is between the mount and the turbo it may be possible to unbolt the mount from the block, take off the hardline, remove the 2 allen nuts, and shimmy the mount up enough to get a new seal in there, or maybe you can even get it completely out, but I don't know if its possible without completely removing the turbo..
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3forall  



Joined: 29 May 2015
Posts: 17
Location: Canada

PostPosted: Sat May 30, 2015 2:07 pm    Post subject: Reply with quote

Fasteddie313 wrote:
If its a leak where the hard line connects to the mount you can snug it up, I think I cut a 19mm open end short for this.. (check size before you cut)

If its a leak between the mount and the turbo you can try tightening the 2 allen nuts with a bunch of extension, universal, and an allen driver. If you dont have an allen driver you could cut about an inch off of the correct size allen wrench and use it between a socket and the nut..

If that doesn't make it stop leaking and the leak is between the mount and the turbo it may be possible to unbolt the mount from the block, take off the hardline, remove the 2 allen nuts, and shimmy the mount up enough to get a new seal in there, or maybe you can even get it completely out, but I don't know if its possible without completely removing the turbo..



The leak is between the inlet flange and the turbo, not where the oil line connects. I did try to tighten it but only one of the two allen bolts are accessible. The one that I managed to get to wasn't going to get any tighter. Getting to the other one is my main objective since I would rather not have to take off the turbo. I guess pictures would explain the best, I just need to figure out how to post them on this site.
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1982 931 - Megasquirt and liquid intercooler
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ideola  



Joined: 01 Oct 2004
Posts: 15506
Location: Woodstock IL

PostPosted: Sat Jun 06, 2015 1:35 am    Post subject: Reply with quote

There is a round profile green rubber o-ring that fits into a groove on the underside of the turbo mounting bracket, and seals against the upper mounting surface of the bearing housing. What usually happens is that the o-ring loses its elasticity, gets compressed, takes on a square profile, which results in the oil leak you describe. No amount of tightening will fix this, the o-ring must be replaced. I believe the OEM part is still available, but it's been quite some time since I last checked.

There is also a copper crush washer for the upper oil feed line. These will leak too, so I wouldn't assume that it's not coming from there.

The drain line also has a larger brown o-ring that suffers from the same failure mode as described above. The OEM version of these are NLA, but you can get the specs out of PET and order a suitable replacement from McMaster Carr.

While you're at it, you should replace the four alu crush washers for the oil cooler lines, and the large alu crush washer for the main banjo bolt that secures the oil filter console to the block. These are quite troublesome to seal, although I've had some success by coating the crush washers with blue loctite and tightening to OEM specs (H/T to Rasta Monsta). I can't recall whether these are still available as OEM parts, but I believe the specs are listed in PET, so you should be able to find suitable replacements inexpensively, again from McMaster Carr.
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GeneT95  



Joined: 07 Nov 2019
Posts: 5
Location: Chesapeake, Virginia

PostPosted: Wed Dec 04, 2019 9:21 am    Post subject: Reply with quote

I'm just bumping this to say thanks to everyone who contributes. Really. I've had a 931 for about 5 months. It's a great running car with a fresh rebuilt engine/turbo/wastegate etc, but I've had to do a couple things (new water pump, cracked ignition switch, chase small turbo oil leak) and having some place to hunt for answers not contained in the manuals is beyond fantastic.

My small oil leak at the turbo inlet was likely due to a loose rear allen bolt. Using 2 locking extensions and a swivel adapter, I taped a allen socket to the swivel (so it wouldn't be left behind) and found the hard to reach allen had 1/2 - 3/4 turn until it was even snug before tightening. Here's to hoping that was the problem.
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924RACR  



Joined: 29 Jul 2001
Posts: 8346
Location: Royal Oak, MI, USA

PostPosted: Wed Dec 04, 2019 11:38 pm    Post subject: Reply with quote

Hope it works for you; to date, every time I've removed the turbo I've found that o-ring (that Dan referenced in his post) to be cooked hard as a rock, no pliability to seal, and needing replacement.

No doubt the heat from the turbo kills it.

I do wonder if Porsche under-specced the original part with respect to temp, and if perhaps the newer green ones hold up better thanks to modern materials science and engineering...

Certainly haven't had any leaks after replacing those, but it's taken turbo removal to make it happen.
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GeneT95  



Joined: 07 Nov 2019
Posts: 5
Location: Chesapeake, Virginia

PostPosted: Thu Dec 05, 2019 10:48 am    Post subject: Reply with quote

Yeah. I'm hoping not. The turbo is newly rebuilt (not by me) in the last 2000 miles. I wouldn't expect a hard o ring but a poorly seated one or something else.

Can the orings of that section be replaced without taking the whole things out? Or can I unbolt just the upper portion and reseat if I need to??

I'm at work, so I don't have a manual with me (shame) so the question may indicate my newness.
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Carrera RSR  



Joined: 08 Jan 2010
Posts: 2022
Location: Somerset, UK

PostPosted: Thu Dec 05, 2019 7:33 pm    Post subject: Reply with quote

Need to drop the turbo to replace the top O ring and all the extra parts to remove do so. Its a painful process. This may mean new gaskets for manifold to turbo and turbo to exhaust unions. Same potentially with waste gate and J pipes. In addition its probably wise to replace all fixings if they are looking crusty.

So to replace a leaky 50cent O ring, it will potentially cost 1-2days labour and several hundred bucks of consumables if you do the job right.......hence PO maintenance may me lacking on a cheap craigslist turbo...

When reinstalling the turbo I use a smear of Loctite very high temp exhaust sealant on all gas and oil joints to try to help the seal. So far so good.....


PS just had an issue with oil pee'ing all over the turbo area. I thought it was the oil joints or turbo. On closer inspection the straight 15mm oil breather hose joining the head breather hard pipe to the oil drain hard line had loosened. I probably failed to tighten early this year when installing new turbo. This was the cause of the oil and thankfully an easy fix and clean up.

You can see the hose above the turbo in this pic
Untitled by stevenmcooper, on Flickr
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1980 931 - forged pistons, Piper cam, K27/26 3257 6.10 hybrid turbo, 951 FMIC, custom intake, Mittelmotor dizzy & cam pulley, H&S exhaust, GAZ Gold, Fuch'ed, Quaife
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