Checking oil level

[sheep911uk]

I know about checking the level with the engine running however since my last 12k service as soon as i take off the oil filler cap the engine coughs and splutters and eventually dies,apart from that the engine runs strong,it has done 91k any ideas!!!!

 

[Guest]

I think the idle should hunt with the filler cap off as the crank case is vented through the oil tank (or is that the other way around?). It shouldn't stall though.

Does your engine start and idle okay normally, because you might be sucking air through the injector seals and this, when combined with removing the oil cap could cause the engine to stall?

 

[sheep911uk]

Starts and idles fine no problem whatsoever thats what is so confusing!!!

 

[Guest]

This is a common one, which I have seen before, but dont remember the answer too, someone one here must know?

Otherwise try ringing the technical advisor for the register - I am sure he can help.

Let us know too.

 

[bones]

Sounds to me like a vacuum leak is masked at tickover by compensating with a richer idle
setting. When you take the oil filler cap off it becomes to much for the injection to cope with and the car coughs and stalls. It doesn't sound like a major leak as you don't complain of poor running. With all the stuff in there it's hard to spot the culprit, likely suspects are a disconnected vacuum tube out of sight at the rear of the engine. Get a bog powerful torch in there and poke your head aroung till you find the culprit. Could be an injextor o-ring as mentioned or a manifold to airbox boot but it's unlikely on an engine of this age. I just replaced all mine on my '78 SC and although they were not nearly as flexible as they should be non were unserviceable. I did find one or two rubber vacuum pipes in need of serious attention though.

 

[Alan_Armstrong]

Bones,

With info like that, you need to be elevated to a higher spanner rating []

By the way, like the buddies idea, have given myself a single rating, cos i got a large box full of 'em!...More seriously, can be available to help, would like to learn more, as have dabbled with motors from late teens, including various owned rally cars, but am cautious
to meddle with my pride and joy until more confident!

 

[bones]

Great another 'Buddy' joins the cause. We should have a 'Buddy' database searchable by location eventually.

 

[Guest]

I also have this same issue, originally I thought it was worn rings. My topend has been redone (and rings) and this still happens. The mechanic did say that my breather hoses have gone brittle and that this can cause the problem - cheap to replace. I also have a K+N induction kit fitted, I have been told that this can also cause the issue.

 

[bones]

HP I'm interested to know how your car felt after you had new rings , at what mileage did you renew them?

 

[Guest]

Dude,
Another sometimes common leak can occur around the inlet manifolds; where they bolt onto the heads. Those are the loverly aluminium sexy curved pipes on each side of the mtr. Held on with socket screws, most are easy to get at. They should all be tight - check torque required. You can find a leak by spraying carby cleaner around the manifolds whilst the donk is running - try and aim it at each joint at a time - wait - if motor speed increases you found the leak.[]
The oil tank is connected directly to the crankcase via the little hose at the top, next to filler cap.
Apart from this breather hose, the crankcase is air tight.
There are also other vac hoses on the left side front, behind heater fan, and below cruise control actuator - in front of the fuel filter. Its here that the vac for brake servo boost comes off I think (from memory) - these could all be possible leak points? You need to get dirty[8D]
have fun,
it'll give you a better understanding of one of the worlds greatest motors ever built!
And no - its not made of glass.
see ya,

 

[bones]

That's a good point about the manifolds when I recently had my engine out (fired it up today) Ifound two manifold nuts were backed off 3/8" although the opposing nut still seemed to hold the manifold firmly against the gasket, they are a sod to check with the engine in.

 

[ClubSport 911]

nd below cruise control actuator -

What's that ???...softies ([])

 

[Guest]

Yeah Steve -
Its useful for crawling along the motorway at 40 mph! Thats what it was designed for I think? They must have known the roads would be congested in 20 years time - smart wern't they?
Believe that?

 

[911sse]

I would agree on the breather hose theory here!!

I replaced both the top hoses on my car, they were split round the back.

The car would run on very rough after removing the cap prior to replacing the hoses.

Once the hoses were replaced, the car goes rough and dies to stall within 5-10 secs.

Just remember and have the car level, at max temp and never fill more then 10mm
from the 2No dots on the dipstick, no matter what the internal guage says!!

Especially if you are a spirited driver. The smoke that might appear on overfilling tells a story!!!


Cheers............................

 

[Guest]

Bones - After the rebuild the car feels like it had bags more power but it didn't seem to rev as easily as I expected. After doing a few hundred miles it seems to have loosened up nicely and now runs as I assume a 911 should (it's my first one). However, the car now keeps stalling at lights when it is cold and I have a slight mellatic rattle on pull away at low revs - it sounds like a heatshield or something is loose, I assume it's clutch related. When it goes back for the post-runin oil change I'll get it sorted as well as get the hoses replaced.