Good day / not so good day

[rover3l]

Well I finally got my remaining 5 active suspension accumulators fitted today. The result is astounding. The level of ride and stability improvement far exceeded my expectations. I have now done all suspension rubber plus 9 accumulators. The ride is pillow soft and the handling razor sharp plus the stability over crests and undulations is unreal. I truely can't imagine a better riding / handling combo

The not so good news is as following

1. After fitting the accumulators there is a noise which sounds like a pump whiring. The pitch of the noise rises and falls with engine revs. It could be air in the system I hope or some other cause that will need fixing. I telephone Keith Bowers (Texasoil) and we discussed possible causes. Could be something unrelated like an idler pulley or a bearing, could be air in the active pump or could be a worn pump

2. I had a CEL and the autoshop diagnosed it to be a leaking injector and a KS. However, as he had replaced a couple of weeks ago a vacuum hose that was split we decided that a first strategy would be to reset the codes and to carry out a fuel rail flush and decarb. He used some computerized device made by Snap On and a fluid suposedly known in the trade as "soap". He did it twice over and apparaently got a ton of carbon out and no pressure loss from the injectors. The result so far is no codes, no CEL and the acceleration from rest is amazing, much stronger and smoother. We will see how it goes over the next week or so

3. Following mention a couple of weeks ago of an oil leak he diagnosed the cause to be the valve cover seal on one side of the engine by tracing it with a UV sensitive additive put into the oil. The leak shows up yellow under a UV light. You guys who predicted this were right. So far it is a very small leak but I am worried that it could cause a fire as it is dripping onto the exhaust manifold? I guess the only solution is to bite the bullet and remove the plenum and get in there. I am not sure whether I want to do this myself or get the mechanic to do it. How many hours do you estimate it would take?

[szh]

I had it done at the dealer. It took them over 6 to 8 hours as I recall on my 1995 Q45 to replace both valve gaskets. Basically, $45 in parts and many $hundreds in labor! I asked them to clean the plenum while they were at it. Which they did for no extra charge, and the engine compartment looked awesome after they were done.

Z

[DAEDALUS]

Plenum's not coming off to do the valve cover. The passenger-side cover is easier to do than the driver-side. Less harness and no EGR or intake in the way.

#2 is not good news?

[rover3l]

Sounds dumb but I don't know for sure which side is leaking but he did say it was the one which was the more difficult and that the leak is dripping on the exhaust manifold. Does this confirm it is the driver side and if so is it possible to do this without removing the plenum?

[DAEDALUS]

The plenum has to come off if you can't get the bypass hose out without breaking it. Most manage. On my car it wasn't possible. The hose was so old it shattered. That was a sign!

[szh]

Plenum's not coming off to do the valve cover. The passenger-side cover is easier to do than the driver-side. Less harness and no EGR or intake in the way.

#2 is not good news?

Hmmm ... did I misread the original post? Is replacing the "valve cover seal" different from what was done to replace both "valve head gaskets" on my Q45? Mine, apparently, required removing the plenum to get to it done(?)

Z

[rover3l]

I am talking about the valve head gasket

[911/Q45]

90-93 have an RTV seal between the cam cover(valve cover) and the head. 94-96 have a gasket in the same place. Very unlikely that the leaking oil would catch fire, but pretty stinky for a classy car like the Q.

[DAEDALUS]

Hmmm ... did I misread the original post? Is replacing the "valve cover seal" different from what was done to replace both "valve head gaskets" on my Q45? Mine, apparently, required removing the plenum to get to it done(?)

Z

Usually referred to as the valve cover gasket, so as not to confuse it with the head gasket. However, it does seal the valve covers to the head.A shop can insist on replacing the hoses that run from the covers to tubes under the plenum in order to warranty their work--the only reason to remove the plenum I believe. Otherwise there could be a vacuum leak and they'd have a comeback, unless they'd accept a waiver of liability from the owner. Can't hold it against them. However, a DIYer can often remove the hose fitting from the cover and not have to remove the plenum. It's worth the risk for a DIYer I think, cause there's virtually no labor overlap if the plenum has to come off later after doing the valve covers.