does a leaky plenum gasket cause vacumn trouble?i have a vacumn problem therefore my heater selector does not always work properly.i have seached for a leak in all the lines,changed the selector control and the check valve.everything is fine for a while then back to same problem.it is a hard thing to figure out because it is an intermitant problem.just wondering if leaky plenum gasket could be the root of my trouble.i have all the symtoms of a leaky gasket 1 litre oil lost bettween changes,loss of mileage,pinging no matter what grade of fuel used. i have 202,000 km on truck so i am likely do.
thanks

 

am i right or wrong?
thanks a bunch

 

first what is your heater doing. the plenum gaskets dont cause a noticable vac loss. to check the plenum, remove the pcv and breather from the valve covers so the only thing on the valve covers is the oil fill cap. place your hands over the open holes for a min, if is is blowing air out, gasket is ok, if sucking in, blown gasket.

 

thanks for the reply,heater is a totaly messed up deal.sometimes delivers air to selected areas othertimes it wont.blower blows like heck with very little air coming out,have checked vacumn lines and all look good.have posted this vacumn trouble before with many responces but still cant figure it out this is why i wondered if leaky plenum gasket would cause a vacumn problem.i am totaly stumped.

 

yes it can depending on how server the leak is. whenmine went out you could feel it in the brakes.

 

thanks tani 1500,what did it do to your brakes?stiff pedal?have to jump on pedal with both feet for fast stops?
i hope the plenum gasket is the problem because i have played with this thing way to long.[:@]