Turbo oil line seals

[Toni Lindroos]

I have the exhaust manifold of my white Turbo off and checked it for straightness with a straight ruler and feeler gauges => about 0,5 mm gap. I also checked another exhaust manifold from my Turbo #2 and just today took it to a machine shop to even out the surface (I measured at least 0,7 mm gap, they shaved off 0,8 mm).

I would like to renew those oil line seals, they are probably over 20 years old and a bit flattened already. The first ring type seal (not an O-ring but a flat one, like a washer) can be replaced with an O-ring. The second one is in the return line junction flange.

I spend several hours calling and visiting different shops today and had no real success for finding suitable replacements... :-( I could try to order from Peugeot but it would take about 3-4 weeks (they order them from factory). I checked many hydraulics shops but I could only find (and bought) some O-rings that were made from nitrile rubber (NBR) but I'm not sure that those are suitable for such a high temperature as the turbo has? Their heat endurance is about -22 to 210 F or -30 to 100 C which sounds too low for me?

I also found (and bought) something better, viton o-rings: -4 to 392 F or -20 to 200 C. The cold resistance of viton worries me greatly. If there's -13 F or -25 C outside and I start the engine, will it leak?-(

Maybe the best material would be silicone: -75 to 392 F or -60 to 200 C. But I couldn't find those locally today without leaving an order.

I would like to put the engine back together tomorrow... So, my options are:

1) Use the old and flattened seals (I don't think they leak yet, however).

2) Use the viton o-rings and hope they will work in winter too.

3) Use the nitrile ones.

I couldn't find answers to these questions:

1) What material are original seals? Silicone? Something even better (what)?

2) How much those seals have to endure heat?

This is really frustrating because I would like to do it right and not just hope for the best and wait for possibly fatal leaks...

[Trevor]

Hi Toni, wondering what you ended up doing? I might have tried to reuse the old ones if i was in the same position and couldn't find replacements. The Silicone sounds like the best option long term.

[Bean]

Aren't the good valve stem seals Viton?

I'd personally use the best fit of the new seals you got - the Viton. The temp is a concern - but it would only stay that temp for only a few seconds after start up. It should still have plenty of sealing capacity - and if they are rated like many other engineered items - they HAVE to have a factor of safety built into them to assure that they don't fail on anything just outside they're operating range.

With that in mind - I'd have no concerns with using the Viton seals...

[Toni Lindroos]

Yes, I think some good valve guide seals are viton.

Well, I decided to put the old original seals back and try to order new from Peugeot... If they are N/A, then I'll try to source some silicon or PTFE (Teflon) O-rings. BTW, the Peugeot part numbers should be (found them from George Nunez's web site):

Oil inlet O-ring: 1166.13

Oil outlet O-ring: 0380.08

The upper one is very easy to replace afterwards but the lower is not so easy because removing and installing the oil flange without removing the turbo is a bit tricky but can be done.

So, now the car is back on the road again and I haven't spotted any exhaust gas or (new) oil leaks yet. ;-) The whole operation was easier than I thought. I took quite many pictures and I'll do an article about it later. It's a simple operation but it may not be so clear for beginners like me. ;-)

Boost gauge shows now about 0,7 bar (10,2 psi). I think it showed about 0,6 bar (8,7 psi) when the exhaust manifold was leaking. When accelerating with WOT, changing gears and then accelerating again it peaked at 0,8-0,9 bar (11,6-13,1 psi)? I really didn't test it much yet.

I'm going to clean the intercooler later just to make sure there aren't any dirt blocking it.