Leaking valve cover gaskets allow oil into heat exchangers. High temperatures under acceleration vaporize the oil which then comes forward. Very common 911 behavior.
Other common behavior is to rectify this by torquing the valve covers-- the correct thing to do is to take everything apart, surface the vale covers, use good gaskets and new crush washers with DIN 985 nylocks (except for concours. . .concours cars have smoke coming from the vents like mine)
1966 911 #304065 Irischgruen
I am struggling with how the oil gets into the heaterboxes. They are in very good condition
Do you have one of those rarities,,,,a completely dry engine? Shine a very powerful flashlight through the fan blades, are the cylinder tops oily or dry?
Early S Registry member #90
R Gruppe member #138
Fort Worth Tx.
i had engine out not long ago. 1000 miles or so. installed new P&C's, cleaned everything up too. of course things could have changed.
and of course the engine still has leaks...geez
In order for oil smoke to get into the heater ducts it almost certainly has to travel thru the heating system,,,,somehow!
Early S Registry member #90
R Gruppe member #138
Fort Worth Tx.
i know it! that is why im looking for some advise or past similar experiences. what do you think about the blowby idea?
Originally Posted by thilmes
I am assuming you adjusted your valves since you are about 1000 miles in? Did you change the oil at like 300 miles and then do a valve adjustment around 1000 or what did you do exactly? Did you reuse any valve cover gaskets or locknuts? Have you actually inspected anything yet? You really need to just crawl under there and look and figure out what the deal is. It's probably pretty obvious.
-Kris Clewell
Professional photojournalist
red decklid club member #1
If you have enough blowby coming out that open oil tank vent to fill up the engine bay at speed, then yes, the engine fan would draw it into the blower housing, from there the air pressure would take it down the heater tubes into the heat exchangers and then to the defroster ducts. Put the stock aircleaner back on and correctly plumb the oil tank breather into the aircleaner and see if the problem goes away. Of course if you just installed new pistons and cylinders why would there be all that blow-by?
Early S Registry member #90
R Gruppe member #138
Fort Worth Tx.
yup. valves adjusted. new gaskets. actually had to do it twice because had a failure of one of the cylinder crush gaskets...
I am with you edmayo. i do not think that the blow-by is there, just looking for possible sources so i can explore them. I'm on the same track. Install factory aircleaner and see what happens. pulled it out last night and started cleaning it up.
Thanks all
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