3/8s NPT thermostat connection points - fan relay & water temp gauge

[cudajames]

At this point of my motor installation, I am working on water temperature gauge (part of a external gauge cluster) and electric fan relay

1991 LA360 Stroked to 408
Eddy 7576 RPM Air Gap - existing 3/8s using for heater hose
Eddy Heads - 60775s

The electric fan relay - thermoswitch is 3/8 npt ( I can use 1/8 npt) - if I want to connect to the intake manifold
Water Temp gauge - capillary is also 3/8 npt with a fixed fitting

I am sure this is common - where and how is everybody connecting these switches/relays?

I did find a water neck spacer that has two 3/8s ports. Anyone using one of these?

thanks for the help/education

 

[sireland67]

That water neck will work fine.

 

[cudajames]

How is everyone else connecting fan relays and water temp gauges on their cars?

 

[sireland67]

Well I have just drilled and tapped the intake on my LD340 on my duster, I found that thermostat spacer after I already drilled and tapped the intake.
I used the spacer on a LD4B on my old truck and it worked fine.
I also drilled and opened up a port on a mag M1 duel plane I had.
The spacer is easier.

 

[TrailBeast]

How is everyone else connecting fan relays and water temp gauges on their cars?

I run an aftermarket temp gauge and sender for a gauge in the factory spot in the cluster, but those thermostat spacers are great for adding a place for the sender.
One thing is you want to use as little extra fittings as possible.
Even one adapter on your fitting will throw your temp reading off quite a bit.
One thing I would be sure of is that the threaded holes in that neck adapter has the correct seat for the aftermarket sender or you will have to run the adapter fitting and it may not let the sensor part of your sender get all the way into coolant.

For fan relays I connect direct to battery positive and a fan ground wire as short as possible.
Then your fan switch can switch the relay.
I like to use a separate relay even though the fan controller I run is capable of handling the load, I would rather blow a 10 dollar relay than a 60 dollar fan controller.
This way the 60 dollar fan controller is only used as a switch and takes a lot less abuse.

 

[mopowers]

How is everyone else connecting fan relays and water temp gauges on their cars?

I ran my water temp gauge to the 3/8 npt fitting on the drivers side of the thermostat and I opened up the 1/4 npt hole to 3/8 npt for the heater hose.

They make plenty of adapters to use the existing holes also.

 

[cudajames]

The thermostat spacer states 3/8-npt which is the same size of the two senders I need to use. And the spacer is about the same cost as buying 1/8-npt fan relay

I am starting to mock up the fan wiring and keep what Trailbeast says in mind. I am getting close

 

[sireland67]

One thing on the spacer I found out, just use a regular gasket on each side and ditch the o-rings, I could not get the o-rings to seal.