Treading Comet

iTrader: (1)

Hey guys I got an 87 gxl that wen I got it I never even noticed the the thermo vacuum valve wax pellet until one day I hear a hissing sound coming from the throttle. When I found the hiss it was the wax pellet leaking air out but not from the two vac hoses nor where it threads in the throttle, it comes from the end. I'm curious, is this normal or is it going bad?

sp0ngebob

iTrader: (1)

theres a known metered vacuum leak at the thermowax pellet. im assuming you mean the one that controls the fast idle vs hot idle.

its all metered by a little passage way that looks like a tiny trench machined into the housing. the gasket is also cut to accommodate it. however, the gasket is no longer made. i had to replace mine so i just cut one from some gasket paper and effectively sealed the leak. The car seems to almost idle smoother with it closed up.

Treading Comet

iTrader: (1)

No its not leaking from there were I can use a gasket. Its leaking from here...

sp0ngebob

iTrader: (1)

oh. that changes things

Treading Comet

iTrader: (1)

Does anyone know if this is ok or bad? Like I said it wasn't doing it b4 so I'm guessing its bad and I want to change it if its bad

jjwalker

That looks like the thermostat for the double butterfly valve. If that is the case, you can take the vacuum lines off of that and cap them off. It's really a useless system to keep idiots from going WOT when the engine is cold.

Treading Comet

iTrader: (1)

I seen something on Atkins with the same terminology of thermo pellet n it was a kind of block spring loaded inside with a bolt threaded behind so it won't come out. I asked them if it's for this part, still no answer but if it is I see what u mean to take it off

jjwalker

You don't have to take it off if you do not want to deal with plugging the coolant passage. You can just leave it there and cap off the vacuum line on the block.

Treading Comet

iTrader: (1)

I understand but like I said its leaking from that area I boxed in the picture. So I may block it off completely and besides I'm taking the intake manifold off soon so might as well do it all at once. Thanks for the help tho

pfsantos

iTrader: (1)

Not exactly certain, but that looks like the thermo valve that controls vacuum to the first secondary plates as you go towards the engine.

It should not hiss. It should either allow vacuum or close it off to the actuator on the plates depending on temp. When cold, the first plates should stay closed at idle then open gradually when the second secondary plates open. When warm, the first secondary plates should stay open, even at idle. Or at least that's how I remember...so check the FSM, Chapter 4A I believe.

The air filter part (end of the valve) is to allow the actuator to go from vacuum to atmospheric pressure when the thermo valve closes/opens.

Treading Comet

iTrader: (1)

Ok so I just saw that the Atkins pellet is not the same as the wax pellet I'm talking about on here.

Atkins thermal pellet is for the eccentric shaft not the thermo vacuum valve wax pellet smh lol

Treading Comet

iTrader: (1)

Ok got u. And yea when I first start her up she idles at almost 2k. So I'll just replace it I guess because I am adding the Atkins actuators in it n if that controls the actuators then I guess its useful.