Intake manifold leak
#2
Doubt it, the coolant system doesn't have anything to do with the vacuum system.
That being said, the manifold may be leaking elsewhere & the vacuum does come from the port behind the throttle body.
Get some brake cleaner, let the engine idle & spray the vacuum lines. When the idle changes - you've found a leak. Also check the line to the vacuum canister ball thing (if equipped) or the canister in the DS fender well. Then the line to the cab & in the cab to the HVAC controls.
That being said, the manifold may be leaking elsewhere & the vacuum does come from the port behind the throttle body.
Get some brake cleaner, let the engine idle & spray the vacuum lines. When the idle changes - you've found a leak. Also check the line to the vacuum canister ball thing (if equipped) or the canister in the DS fender well. Then the line to the cab & in the cab to the HVAC controls.
#4
it won't cause it, but may another symptom of the same problem. the plastic reinforced intake gaskets are quite brittle when they get older. make sure it isn't allowing coolant into the intake valley and contaminating your oil. it could have other cracks that are causing a vacuum leak.
#5
In another amazing coincidence I bought my 1998 Jimmy from a guy who thought the head gasket was bad. I told him it was most likely the intake manifold gaskets but he didn't believe me. I got it for $1200.
#7
thanks guys. I think i have isolated my vacuum leak to my HVAC system, i thought for a minute that it might be related to my 4wd issue. I did a number of tests after replacing most of the vacuum lines. Off to the shop to see if they can figure out this noise coming from my 4wd system. damn
my intake gasket doesnt leak too bad. i tightened the bolts a little about 2 years ago and it has been pretty good *knocks on wood*
my intake gasket doesnt leak too bad. i tightened the bolts a little about 2 years ago and it has been pretty good *knocks on wood*
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blazerdan
2nd Generation S-series (1995-2005) Tech
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07-14-2005 12:51 AM