• Welcome to the Pontiac Trans Am Community, the Official Home of the PTA! Sign up for a (FREE) account today!

'79 Olds 403 Parts

darrenbenjamin73

New member
Joined
Jul 27, 2019
Messages
2
Reaction score
4
Points
3
Location
Virginia
I'm having a helluva time replacing two parts that attach to the intake manifold. Can anyone help? The first is called a temperature sensor, according to the diagram below. This is not to be confused with the temperature sending unit, which is installed toward the front of the manifold.

Vacuum Diagram.jpg


To complicate matters, the temperature sensors I'm seeing online have an electrical hookup. My original--if it is in fact the original and if it is actually a temperature sensor, looks like this:

IMG_05812.jpg


Notice that it isn't an electrical hookup but a hose hookup. To this novice, this doesn't look like a temperature sensor at all but instead a simple 1-port manifold vacuum fitting. What do you think?

The second part I'm looking for is a 2-port manifold vacuum fitting, as circled in yellow in the diagram above. The manifold opening measures 1/2-20 but the fittings I'm finding online are all 3/8. I'm pretty sure the second port connects to the brake system. Here's the pic of the original:

front manifold vacuum fitting _3_.jpg


Thanks for taking the time to read this far and for any insights you can provide to point me in the right direction.
 
Last edited by a moderator:

Aus78Formula

Well-known member
Joined
Feb 4, 2025
Messages
76
Reaction score
139
Points
33
Location
Australia
A super old post that anyone could have corrected.

Don't confuse intake fittings with those on air cleaner.

Vacuum diagram vs emissions.

And no, the rear vacuum port services the dash heater control unit, and the brake vacuum comes from the rear of carb.

Neither are shown on the diagram.
 

darrenbenjamin73

New member
Joined
Jul 27, 2019
Messages
2
Reaction score
4
Points
3
Location
Virginia
A super old post that anyone could have corrected.

Don't confuse intake fittings with those on air cleaner.

Vacuum diagram vs emissions.

And no, the rear vacuum port services the dash heater control unit, and the brake vacuum comes from the rear of carb.

Neither are shown on the diagram.
Thank you for the reply.

Yes, it's an old post and I've come a long way since then.

I cringed when I re-read my original post!

Hopefully your corrections help the next guy!
 

Aus78Formula

Well-known member
Joined
Feb 4, 2025
Messages
76
Reaction score
139
Points
33
Location
Australia
Totally fine, was more that no one had replied to correct or even attempt to answer, and the details are fairly standard GM.