Vac problems

cruising down the road i lose vacuum and heater blows in dash not defrost i let off of gas and heat comes out then 4 sec. it goes back to dash ? any ideals

Find the vacuum leak and repair it.

where to look

First, look to the vacuum line that runs from the engine to the firewall. There should be a check valve to prevent loss of vacuum to the dash controls when the engine vacuum drops. I’ll be the vacuum lines are cracked or degraded. With a 13 year old van, bad vacuum lines are very common.

the vacuum lines look good i am tiring to find a check valve my local dealer had no ideal what i was talking about i have another guy looking for one

Try the ‘HELP’ section at the local auto parts store. It has a bunch of small stuff like this. These parts are made by Dorman. Here is a page at The first valve is what youor looking for.,extras,1,subgroup,Valve,parttype,318