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That was called a Thermo Vacuum Switch (TVS) in 1969. I don't know the application specifics for 1969, but Olds generally installed them on cars which were in greater danger of overheating -- such as cars with A/C. teh TVS serves as a last-ditch effort to cool an idling engine when the coolant temp gets real high. You generally don't need it; it's more a question of originality.
I assume you realize that two of the ports are broken off your TVS?
That was called a Thermo Vacuum Switch (TVS) in 1969. I don't know the application specifics for 1969, but Olds generally installed them on cars which were in greater danger of overheating -- such as cars with A/C. teh TVS serves as a last-ditch effort to cool an idling engine when the coolant temp gets real high. You generally don't need it; it's more a question of originality.
I assume you realize that two of the ports are broken off your TVS?
Thanks for the info. While cleaning this thing up we stumbled upon it and it wasnt hooked up and wasnt sure the exact routing of it. Do you know where to find a diagram? (And yes we know its broken but havent been able to find one yet. )
Does anyone know where to get a vacuum hose diagram for my car?
In the future, it would be helpful if you told us what your car IS... the mind reading thing STILL isn't working.
ASSuming we're talking about the 69 in your avatar photo, then get a 1969 Chassis Service Manual, which will have the diagrams.
The thermal vacuum switch is used on cars that run the vacuum advance off of ported vacuum. Since ported vacuum is zero at idle, this can cause the car to overheat when idling in traffic. The TVS senses coolant temperature and switches the vacuum advance to full manifold vacuum if the car starts to overheat. This increases vacuum advance at idle and lets the car run cooler. The use of ported vacuum for the vacuum advance is an early emissions control that was intended to reduce NOx emissions. I'm guessing that the reason why your car doesn't have the TVS installed is that the distributor is now being run off of manifold vacuum at all times. This is not a problem. Reinstall the TVS only if you care about being 100% factory correct.
In the future, it would be helpful if you told us what your car IS... the mind reading thing STILL isn't working.
ASSuming we're talking about the 69 in your avatar photo, then get a 1969 Chassis Service Manual, which will have the diagrams.
The thermal vacuum switch is used on cars that run the vacuum advance off of ported vacuum. Since ported vacuum is zero at idle, this can cause the car to overheat when idling in traffic. The TVS senses coolant temperature and switches the vacuum advance to full manifold vacuum if the car starts to overheat. This increases vacuum advance at idle and lets the car run cooler. The use of ported vacuum for the vacuum advance is an early emissions control that was intended to reduce NOx emissions. I'm guessing that the reason why your car doesn't have the TVS installed is that the distributor is now being run off of manifold vacuum at all times. This is not a problem. Reinstall the TVS only if you care about being 100% factory correct.
You ASSumed correct. It is for a 69 H/O and it is all factory. Thanks for the info.
The "DCM" gives you the functional connections, but if you want to know how it was T-ed into other vacuum lines and/or connected to other devices (TCS, OAI vacuum motor, transmission vacuum modulator) you still need the proper vacuum diagram.
You need a 1969 CSM which shows the diagrams. I believe it was referred to as a TVS even in 1969 (not positive but the CSM would be the definitive source). I thought they all had three ports, but again - the 1969 CSM should be definitive. Maybe you don't have the OEM model?
My 1969 442 Ported Vacuum Switch, only has two hose outlets.
Which goes where ???
Thanks, neilm
The original TVS has THREE ports. Yours has been replaced with an incorrect one, apparently. A photo would help us identify it. And Oldsmobile calls it a Thermostatic Vacuum Switch, thus TVS. Pages 6K-9 and 6K-10 in the 1969 Chassis Service Manual have the hose connections.
This is what the correct, factory TVS for a 1969 looks like. You will note if you look closely that the ports are labeled "C", "D", and "M", which is what I told you when you asked this same question on May 6 in THIS thread.
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Dcm dcm dcm
