Temp Sensor for 3.5L v8

N

NMEXPAT

Well-known member
I'm feeling super frustrated and really stupid. I'm in the middle of installing an edelbrock intake manifold and carburetor.

From reading the various edelbrock conversation threads on the internet, I just assumed my water temperature sensor would just screw into the edelbrock manifold.

It's doesn't screw in. It's the "right" diameter, but it doesn't want to screw in easily. I'm also hesitant to force it because of the aluminum and the brass and don't want to cross thread. On the original rover manifold it's easy to thread by hand.

another threading problem. I bought a set of Mr gasket Aluminum thread plugs NPT from summit racing when I ordered. None of them thread into either hole, water temp (1/2" hole) or fuel runner hole (3/8").

What am I missing? Am I being a baby with trying to screw these plugs and sender into the hole?

Again feeling super stupid at this point.

Thanks in advance.
 
N

NMEXPAT

Well-known member
Well I'm not a complete idiot. I called Edelbrock tech help line. Turns out both holes are 5/8" diameter with 18 thread count. No wonder non of the plugs I bought won't work. Same for the water temp sensor.

Made a quick trip to home depot. Bought a 5/8" 18 bolt, threads easily!

How come no one has mentioned this in any of the other 4 bbl threads?

hopefully this helps someone in the future.
 
85RED110

85RED110

Well-known member
I installed a FiTech Go-EFI on my 3.9 V8 last year, and when installing the new Edelbrock 2198 manifold, I had trouble threading the water temp sensor into the manifold. The sensor was an off-the-shelf AC Delco unit, 3/8 NPT threaded. The manifold was supposed to be 3/8 NPT as well, and even phone calls to both Edelbrock and FiTech tech support hotlines confirmed both should be 3/8 NPT, I still couldnt thread the sensor in. I ended up having to order a 3/8 NPT tap, and re-tap the manifold to make it work. Didnt take very much, so I think the factory port hadnt been cleaned out well enough (or at all) in the finishing process. Was frustrating, but I got it to work eventually.
 
R

Red90

Well-known member
5/8 UNF is the normal temperature sender. You said 1/2? so I assumed it was something strange.
 
N

NMEXPAT

Well-known member
Red90 said:
5/8 UNF is the normal temperature sender. You said 1/2? so I assumed it was something strange.
Click to expand...

I didn't know 5/8" UNF is the normal temperature sender. The one on my stock manifold isn't that diameter and thread pitch.

I mistakenly wrote 1/2".

I also didn't know the outer diameter of 3/8" NPT is 0.675", which is larger than 5/8" = 0.625.

It also didn't help the existing water neck on my truck has two additional temperature sender / switches, which are even larger diameter. The existing water neck doesn't work with the Edelbrock intake manifold. I'm slowly learning, which is tough when your truck isn't outfitted like others. Thanks for the help.
 
Robert

Robert

Well-known member
NMEXPAT said:
It also didn't help the existing water neck on my truck has two additional temperature sender / switches, which are even larger diameter. The existing water neck doesn't work with the Edelbrock intake manifold. I'm slowly learning, which is tough when your truck isn't outfitted like others. Thanks for the help.
Click to expand...

Those are switches

Top one when hot closes the circuit that turns on the electric fans
Bottom one when hot opens the ground circuit on the ac clutch relay
 
Robert

Robert

Well-known member
Is it this one? It is 5/8-18
 

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N

NMEXPAT

Well-known member
Robert said:
Those are switches

Top one when hot closes the circuit that turns on the electric fans
Bottom one when hot opens the ground circuit on the ac clutch relay
Click to expand...

THANKS Robert! Do you have any more information about these switches like diameter and thread pitch? I'm asking because it would make my life easier on possibly ordering an adapter. My new water neck doesn't have the ability to connect like the old one. Sounds like I need to buy a hot side adapter?

Here are two photos of my old stock water neck with the two elmwood sensors
https://photos.app.goo.gl/OhH2dH5n9YNifCog2
https://photos.app.goo.gl/fYrrkuIF9nUl9hKb2

It might be related, but on the dash there's an aftermarket switch labeled fans. I think this might be wired to the relay, to turn on the fans regardless of temperature. I haven't been able to get them to turn on, but I haven't really tried besides flipping the dash switch. I haven't tried tracing the many after market wires through out the truck.

I realize I'm asking some real basic and dumb questions, but I've been away from home for work and it's been tough to devote the time to chase these details down.

Really appreciate the help.
 
N

NMEXPAT

Well-known member
Robert said:
Is it this one? It is 5/8-18
Click to expand...

That looks just like the one I pulled off.

I tried again to thread it into the edelbock manifold. First I ran the 5/8"-18 bolt to make sure the threads are clean.
Now the old stock temperature sensor threads in easily.

So basically I was being too cautious, in other words a BABY about messing up the threads on the aluminum intake. I've messed up threads before so I'm gun shy as it's cost me in the past.

THANKS!
 
Robert

Robert

Well-known member
NMEXPAT said:
THANKS Robert! Do you have any more information about these switches like diameter and thread pitch? I'm asking because it would make my life easier on possibly ordering an adapter. My new water neck doesn't have the ability to connect like the old one. Sounds like I need to buy a hot side adapter?

Here are two photos of my old stock water neck with the two elmwood sensors
https://photos.app.goo.gl/OhH2dH5n9YNifCog2
https://photos.app.goo.gl/fYrrkuIF9nUl9hKb2

It might be related, but on the dash there's an aftermarket switch labeled fans. I think this might be wired to the relay, to turn on the fans regardless of temperature. I haven't been able to get them to turn on, but I haven't really tried besides flipping the dash switch. I haven't tried tracing the many after market wires through out the truck.

I realize I'm asking some real basic and dumb questions, but I've been away from home for work and it's been tough to devote the time to chase these details down.

Really appreciate the help.
Click to expand...


You could probably get by with shorting the lower wires and ignoring the upper. The fans will still go on when the ac is turned on, you'll just lose overheat fan kick on so make sure the fan clutch is good. Just tape the wires up and move them out of the way until you're ready to ditch the carb and go efi ;)

The fuse for the fan is one of the 2 middle glass fuses on the far left of the interior fuse panel. The relay for the fan and ac clutch is behind the power steering pump. Its a single throw dual pole relay like the fuel pump relays on efi 3.9 trucks so don't try to put a generic parts store relay in its place.
 
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