Vaccum Leaks

[CASEY79WESTFALIA]

I am going over my engine and am searching for vaccum leaks. I still cannot seem to find any but am curious where others have found vaccum leaks before on there engine. I am going to replace the brake servo hose and the charcoal canister lines(are these problem areas?).

[Amskeptic]

I am going over my engine and am searching for vaccum leaks. I still cannot seem to find any but am curious where others have found vaccum leaks before on there engine. I am going to replace the brake servo hose and the charcoal canister lines(are these problem areas?).

Vacuum leaks can occur wherever there is a hose. They can also occur in unlikely places, like the dipstick or oil filler on L-Jet engines. The throttle housing to intake plenum gasket can leak. Breather covers on late engines can crack very subtly at the little round plastic cap on top or at its gasket surface.
People say propane is a good leak detector, but if your mixture is slightly rich to begin with, it might be hard to ascertain exactly where the leak is.
Colin

[satchmo]

Cracked hoses on the fuel vapor recovery system (charcol canister, etc.) should not be a cause of vacuum leaks. Cracks here can cause your bus to smell like gas, however. And the rubber hose connecting two metal fuel vapor lines tucked up under the spare tire well is a known cause of gas leaks when your gas tank is full, so make sure that one is intact.

Tim

[CASEY79WESTFALIA]

Okay looks like I have some more searching to do. I have a slight stumble at idle which is leading me to believe I have a vaccum leak.

[DurocShark]

Anything rubber.
Anything with a rubber hose attached.
Anything on the intakes.

You get the idea.

I had a vacuum leak in my fuel pressure regulator. I thought it would be leak proof. Hahahaha!

[CASEY79WESTFALIA]

Could not having my heater tubes hooked up contribute to higher then accepatable head temps. By heater tubes I mean the ones that hook to the back of the heat exchangers and connect to the heater channel duct. It seems possible that the hot air coming out of there could contribute to my 10-20 degrees of head temp that I would like to get rid of. Is it a possibility!!!

[satchmo]

Short answer: no. The heated cooling air dumps out the flapper box in this location when you don't have it directed up to the passenger compartment, so it shouldn't make much difference with the heat tubes disconnected at the 'front' of the heat exchangers (you meant front, rather than back, right?).

Tim

[Amskeptic]

Missing ducts at the front would not be as serious, but at the rear, particularly if the tubes leading through the tins into the engine compartment are missing, you can easily see hotter temps. Both from the heat blowing up into the engine compartment as well as less air flow through the exchangers to cool the exhaust pipes.
Colin