Purging air from cooling system on 99 Quest?

[pcella]

I have replaced the thermostat in my 1999 Quest and now I am trying to get the air out of the engine block. My Haynes manual says that there is an air vent cap on the top of the intake manifold and another behind the throttle body, but I can't find either. The heater is nice and hot and the temperature gauge remains normal and stable until air starts bubbling into the overflow tank. Then the temperature starts climbing above normal. If anyone can offer help on how to get the air out, I would be very appreciative.

[IH8SPM]

I am not sure right now of the location but if you want you can just leave the cap loose on the radiator till it bubbles then close it. I will look for the location and get back to you.

[pcella]

Thanks for your help. I may just have to break down and get one of those vacuum purge and fill devices.

[molhannah]

Check around the themostat housing for a bolt with a gasket under it. Not sure about your year and model, but a lot of the Nissans have this. It will be a socket head bolt, take a 10mm socket or wrench and loosen to bleed of trapped air.

[pcella]

Thanks to everyone for their help and advice. I finally paid to see the technical service bulletins for the Quest at alldatadiy.com. The correct purge procedure for this vehicle is to pull a vacuum on the cooling system and then backfill with coolant while it is still under vacuum. I borrowed a vacuum pump and some fittings from work to do this and now the cooling system has never worked better. For those that do not have access to a vacuum pump, uview and others make tools for doing this (that use shop air to pull a vacuum) for under $100.