help my friend - his 911sc engine dies when checking oil

[groovzilla1959]

all,
my friend has a 1980 911sc and his engine dies when he removes the oil cap to check the oil. dies within a few seconds of removing the cap.

heard something about a vacuum funnel that can be missing on the rennlist website but can't find anything of help.

any help appreciated!

[Oh Haha]

This should explain things>Engine wants to die upon removal of oil filler cap?

Check for the restrictor in the breather line. If it's in place, look for other sources of a vacuum leak.

[tazzieman]

He has a vacuum leak. Many threads here on testing for these; some are easy to find and others , a mystery train!

[groovzilla1959]

thanks for the feedback - i checked the oil breather hose that comes off the oil filler neck leading to the rear engine compartment behind the fuel distributor connected to the intake.

there is no plastic restrictor located anywhere along this rubber hose. i assume this is the issue and will do a test using some vise grips and carefully clamp the hose down and see if this helps the car idle when the oil cap is removed.

[vash]

Originally Posted by groovzilla1959

thanks for the feedback - i checked the oil breather hose that comes off the oil filler neck leading to the rear engine compartment behind the fuel distributor connected to the intake.

there is no plastic restrictor located anywhere along this rubber hose. i assume this is the issue and will do a test using some vise grips and carefully clamp the hose down and see if this helps the car idle when the oil cap is removed.

it's brass or something. pay attention, it goes in with the narrow end facing..up i think.

[pharlap71]

on an'84 the two big hoses (crankcase breather/ vapor hose to intake elbow) at the oil filler will interchange and cause this problem, not sure on a SC.

[midnight911]

how the restrictor looks like... 84 carrera example.

Breather Hose Restrictor

[diy83sc]

Here's a thought. I recently had the engine out to replace my cracked airbox. After getting the engine back in the car and started, the warm idle was much lower without the extra air spaces of the old airbox. When I checked the oil, same problem - engine stalled. Maybe the idle is too low (less than 900), enough to be on the cusp of stalling when the cap is removed?

[boyt911sc]

Originally Posted by Oh Haha

This should explain things>Engine wants to die upon removal of oil filler cap?

Check for the restrictor in the breather line. If it's in place, look for other sources of a vacuum leak.

Wayne,

The in-line restrictor (cowbell) is not used in SC's. They are installed in 3.2 engines.

Tony

[Jdub]

I agree r.e. the SC (at least my '78, anyways) not being set up with the cowbell.

Having just taken that hose out along with the rubber plenum it attaches to I can point to the barrel-shaped, brass item that slides into the hose where it attaches to the plenum. This is a two-part piece, filled with a brass mesh (Brillo) type material, with a series of holes across its face that looks most like an old shower head. It appears to restrict via holes and catch oil by interference (i.e. Brillo mesh).



Purged this of the old oil, removed same from plenum and throttle body. My original query was to question how 1/2 on the dipstick could cause this amount of oil within the hose > "shower head" > plenum > throttle body.

[MMiller]

Originally Posted by pharlap71

on an'84 the two big hoses (crankcase breather/ vapor hose to intake elbow) at the oil filler will interchange and cause this problem, not sure on a SC.

+1.... this is what caused the same problem on my 88. Someone had misplace the hoses according to my mechanic

[Oh Haha]

Engine died while checking oil and other Q's