I took apart my intake manifold on my 1998 monte carlo and I am missing one vacuum hose that comes out the top intake on the passenger side. Can not find where it goes. Any answers will help. Also where I can purchase this hose not sure if they sell them at auto zone or checkers. PLEASE HELP ME!!!!!

I don't know if top or bottom, but the heater core inlet will be the hose coming from either the intake manifold or a fitting on a cylinder head. The outlet from the heater core goes to the front of the engine, it goes into the water pump. I think all GM engines are like this, and almost all engine designs likewise. On a 1992 3.8L, for example, the heater core inlet hose comes from the intake manifold on the passenger side. The heater core outlet goes into a fitting on the water pump (lower front of engine).

nipples on intake manifolds are used for vacuum access ports so check for a vacuum hose broken off, missing vacuum gauge hose ,PCV valve hose ,anything that requires vacuum to operate-gear box operation.

The age of your vehicle also guarantee's a vacuum leak. It may sound silly but the truth is rubber grommets, and hose's shrink and dry out over time and the harsh environment under the hood makes it worse. Check all vacuum lines and fittings attached to the intake manifold, valve covers (pcv valve), and be sure to check for a vacuum fitting on top of the intake just behind the throttle body. Does it fit tight in the hole? You can seal loose fittings with a high-temp RTV (Red) silicone sealant/adhesive. Several small leaks add up and your engine, heat/AC, and transmission will be all to glad to tell you about it.

What kinda shape are the fuel filter and pump in?

check all vacuum hoses for leak, if there good check for vacuum leak around intake manifold or at manifold gaskets.

Top of the waterkneck on the intake manifold. Pop the hood and trace the top radiator hose to the top of the engine, where it is clamped on is the waterkneck just under that is the thermostat. I think 2 bolts hold it on.


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POSSIBLE CAUSES OF MISSING AT LOW SPEEDS. WEAK SPARK AT IGNITION SYSTEM, BAD SPARK PLUGS + WIRES.STOPPED UP FUEL FILTER. DIRTY FUEL INJECTORS,VACUUM LEAKS AT HOSES OR AT THE INTAKE MANIFOLD, LOW CYLINDER COMPRESSION.

Try replacing the radiator cap. when they get old they let coolant out before it gets hot, a new one should fix the problem.

Cheers, Timo.

Probably a vacuum line. Most heater controls are ran by vacuum and their is one vacuum line that goes from the troddle body to the firewall on the passenger side of the car. Check for a broken hose.

it is most likely coming out of the weep hole at the water pump or the plastic fittings on the water pump to upper intake manifold they are black in color ands are L shaped with O-rings

Check for vacuum leaks at the intake. Check the vacuum hose from the air intake tube to the valve cover.