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So I’m smoke evap testing my vacuum system. I inserted the hose in the system and I got a leak from the small nipple below the intake manifold ( circled item ) at the back. What is this and does that little hole need to be capped with that orange piece or is it supposed to be open to the atmosphere?
Ok I found that it is called a Thermo valve. Evidently once the car heats up a valve opens allowing gases to go to a charcoal canister. However nothing I read explained the little orange cap over that little nipple next to it. I have a turbo and I noticed the naturally aspirated engines don’t have the little orange cap and nipple. Can someone explain what this does?
Also I’m not sure if my vacuum leak is caused by this little open nipple. I added smoke to the vacuum system through the vacuum line that went to the heater control that feeds this particular thermal valve. What is the best place to test for leaks with a smoke system if this location is not sufficient
Rule #1 when you post a problem - State the year and model of your car.
But yes, it is a thermo valve and no it shouldn't blow smoke during your test. Get a new one. They are 30 years old, brittle, and break. And connect the small rubber hoses to it in accordance with the vacuum diagram sticker in your engine compartment.
It’s an 86 951. Just to be clear its blowing smoke out the nipple the orange cap is covering Not the other two hose connectors. In my case the orange cap has is not seated and exposed the nipple (see first image above) which is just a small hole. That is where the smoke is coming out from. Would smoke coming out this nipple constitute a vacuum leak?
06-08-2019, 04:19 PM
Vacuum leak?
