what's this thingey do??

[78Suburban]

my old '66 didn't have this fitting on top of the t-stat housing.. whats it for? 1)there's a line running into the carb, 2) a line running into the vaccume advance on the distributor, and 3) line just laying there with some sort of broken plastic fitting and piece of rubber hose...

 

[dremu]

my old '66 didn't have this fitting on top of the t-stat housing.. whats it for? 1)there's a line running into the carb, 2) a line running into the vaccume advance on the distributor, and 3) line just laying there with some sort of broken plastic fitting and piece of rubber hose...

Well, it switches vacuum, liek a solenoid, based on water temperature. I'd guess it advances the dizzie more or less based on whether the engine is warm?

-- A

 

[big83chevy4x4]

its a temperature operated vacuum switch. ive only seen it on the 81 and newer trucks, but not all of them either.

 

[RaisedK5]

Its some sort of thermostatic switch. If its attached to the spark advance its probably like my 69 buick. At normal temp it supplies ported vacuum to the dist. at high temps it supplies full manifold vacuum to the dist at idle. the theory is (at least on my 69) at idle, full manifold vacuum will pull higher advance and raise the rpm of the motor thus spinning the fan faster to cool off the engine.

 

[78Suburban]

what about the 3rd little line with the plastic fitting and piece of broken rubber hose, what's that?

should I just take that pos of there and get a regular t stat housing? I've been seriously considering putting on my old edelbrok manifold and carb on there anyway.. might could kill 2 birds with 1 stone

 

[1979jimmy350]

it might also feed your EGR valve so it will only open up after the engine has warmed up

 

[az-k5]

I have that on my 79. only it has 6 little vacume hoses on it. (I counted)

 

[4X4HIGH]

my old '66 didn't have this fitting on top of the t-stat housing.. whats it for? 1)there's a line running into the carb, 2) a line running into the vaccume advance on the distributor, and 3) line just laying there with some sort of broken plastic fitting and piece of rubber hose...

The proper name of that is a thermal vacuum switch. Those are used for various different things such as distributor vacuum delay, egr vacuum delay EFE valve and other things like that. Get a book that covers your year vehicle and look under emissions items and you might find a schematic on it, also usually under the hood or on the radiator support there will be a vacuum diagram if nobody has already removed it or it hasn't deteriorated.

 

[pauly383]

Your upper radiator hose is starting to split . Don't overtighten the next one .

 

[78Suburban]

what if I take it off and just run a hose from the carb to the distributor.. would this be ok? I am by no means trying to be emmisions compliant.

 

[CyberSniper]

Trace them down. If you have a 700R4 it can also be used to keep the torque converter locked up until the motor reaches operating temperature.