FJ40 1975 2F Aftermarket Coolant Sender Location and Adapter Advice Request (1 Viewer)

[jlasey]

Greetings! I could use some help locating an aftermarket coolant temp sender and choosing an adapter. According to the research I’ve done on this site, I have found the following:

Location 1&2 = 1/2” BSPT(top of head)
-depth = ~14mm
-if you use these locations with an oem sender you probably need a 1/2”bpst to 16mmadapter (Toyota 90404-16160 Union)

Location 3 = 3/8”BSPT(thermostat housing)
-I’ve read this is a good spot to put an aftermarket sender.
Location 4 = 3/8” BSPT (drain plug)
-this is where my current broken sender is located. I hear this is a terrible spot because the engine is cooler at the bottom. I personally don’t like it because it makes changing the coolant awkward and means you end up draining a ton of fluid to change.

So, now for the question part. I have an aftermarket auto gage sender with a 1/2” npt adapter. Would location 1or 3 be better? Has anyone found a descent adapter for either?

Edit: from a 2011 thread I just found “you can use an NPT in a BSPT in 1/2” size or greater”

 

[rkymtnflyfisher]

I run an aftermarket temp gauge at the #2 location in your post, it's an Autometer, and I believe it came with the correct adapter to screw right in.

 

[jlasey]

I run an aftermarket temp gauge at the #2 location in your post, it's an Autometer, and I believe it came with the correct adapter to screw right in.

Wow. From everything I’ve read on here they didn’t sound like an option. Did the adapter screw directly into the block or into the adapter hat the sender screws into?

 

[rkymtnflyfisher]

Wow. From everything I’ve read on here they didn’t sound like an option. Did the adapter screw directly into the block or into the adapter hat the sender screws into?

I just realized that mine is an electric gauge.

 

[jlasey]

I just realized that mine is an electric gauge.

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great picture! How long do you think your temp probe extends into the block?

 

[rkymtnflyfisher]

great picture! How long do you think your temp probe extends into the block?

I don't remember, but I am pretty sure that the coolant galley is pretty deep.

 

[jlasey]

I don't remember, but I am pretty sure that the coolant galley is pretty deep.

I just removed the square plug at location #1. Looks like it’s 14mm deep.

 

[jbee]

@ToyotaMatt is your guy. I think his website is vintageTeQparts.com
He sells the adapters for those coolant sensors.

 

[rkymtnflyfisher]

I just removed the square plug at location #1. Looks like it’s 14mm deep.

Interesting, I thought it was deeper than that, but it does cross right over the top of the 2 intake ports back there, makes sense.


I think with the right adapter it should put the probe at just the right height.

 

[jlasey]

This is where I ended up for now. It’s too tall but I can tell you:
-the 1/2”NPT definitely threads into the BSPT
-a “1/2” NPT close short nipple” Would be better than the nipple I purchased.
-a 40mm tall 1/2”NPT adapter would be ideal

 

[Pighead]

Autometer

 

[jlasey]

Autometer

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rkymtnflyfisher Was also able to install his with a fairly shallow adapter like that. The electric senders from auto meter may be shorter or something. Thanks!​