# 1969 GTO Air cleaner vacuum line and preheater stove shield



## TxGTO69 (Dec 2, 2020)

So I am about 95% sure this pluged vacuum line goes to my dual snorkle air cleaner, please correct me if im wrong. My vehicle is pretty much original when I purchased it, the only thing I found aftermarket were the side view mirrors. When I purchased this car this line was plugged and I believe it was plugged because a vaccum line barbed fitting was broken on the air cleaner. This fitting that is broken would have held a vaccum line that would go to this location on the intake, so I believe the prior owner just plugged it. SOOO I want to reinstall this line and make everything functional again. From my research the photos Ive seen of the dual air cleaner it uses a preheater stove shield which I can see a provision for on my air cleaner, my car did not have this preheater stove shield either it was removed or it was not equiped with one. My question is...if I reconnect this vacuum line will I need to find this preheater stove shield and tube to connect to the air cleaner, or will it function normally without the preheater shield? I am in Texas, so I dont know if this shield is really warranted?


----------



## O52 (Jan 27, 2019)

Thats the intake fitting for the snorkel temperature valve mounted inside the air cleaner. From the temperature valve, the line is then T'd to open both snorkels at the same time.
Default position of the snorkels is closed. As the incoming air is heated by the preheater stove, the temperature valve opens allowing vacuum to the snorkel vacuum cans opening the snorkel flaps.

You can bypass the preheater stove and temperature valve by running a vacuum line directly from the intake to a T then to the vacuum cans.

Preheated air aids in engine warm-up. Not required unless you have smog checks, but it is helpful.


----------



## TxGTO69 (Dec 2, 2020)

O52 said:


> Thats the intake fitting for the snorkel temperature valve mounted inside the air cleaner. From the temperature valve, the line is then T'd to open both snorkels at the same time.
> Default position of the snorkels is closed. As the incoming air is heated by the preheater stove, the temperature valve opens allowing vacuum to the snorkel vacuum cans opening the snorkel flaps.
> 
> You can bypass the preheater stove and temperature valve by running a vacuum line directly from the intake to a T then to the vacuum cans.
> ...


Very helpful. the P/O must have modified the snorkle because both flaps are in the open position. Thank you for the information, very helpful.


----------



## O52 (Jan 27, 2019)

Arggg. I should have looked in the book than shooting from the hip. Mine are open without vacuum. so...

Default position of the snorkels is open. As the incoming air is heated by the preheater stove, the temperature valve closes with increasing temperature (105*) shutting off vacuum to the snorkel vacuum cans and opening the snorkel flaps. 
During WOT operation the flaps completely open regardless of underwood temperature.


----------



## TxGTO69 (Dec 2, 2020)

O52 said:


> Arggg. I should have looked in the book than shooting from the hip. Mine are open without vacuum. so...
> 
> Default position of the snorkels is open. As the incoming air is heated by the preheater stove, the temperature valve closes with increasing temperature (105*) shutting off vacuum to the snorkel vacuum cans and opening the snorkel flaps.
> During WOT operation the flaps completely open regardless of underwood temperature.



Is this information in the service manual? I briefly tried to find it. Without the stove in place I wonder if I should try to make it functional again? Sounds like if I attached the vacuum line without the preheater stove as you stated above to bypass, the flaps would stay closed all the time with the constant vacuum except for WOT? Sounds like I should leave it plugged until I have all the elements to make it functional.


----------



## O52 (Jan 27, 2019)

Its in the diagnosis manual. 

The flaps would close with constant vacuum. I apologize for leading you (and others) astray.


----------



## TxGTO69 (Dec 2, 2020)

O52 said:


> Its in the diagnosis manual.
> 
> The flaps would close with constant vacuum. I apologize for leading you (and others) astray.
> 
> ...


Makes complete sense now. Ive never seen/heard of that manual, I need to find one. No need to apologize, I appreciate the help.


----------

