Autometer mechanical water temp gauge sending unit

Last question on this. I promise. I'm as tired of asking you as you are of being asked but a big thanks for your help and patience.

Car is a 2004 Mustang GT. Bone stock.

I know where the water coolant drain plug is in the driver's side of the block. Looks like 3/8 inch NPT.

First is a picture of the sending unit. From what I've read on Stangnet and depending on who to listen to, this will either bottom out when installed in this spot or will be a perfect fit.



So, before I get into this again, will this sending unit fit properly into the specified location? Will it fit using just the blue connector? It seems like it won't because the tapered part of the sending unit won't have anything to snug up against in the water jacket.

The gauge also came with the red 5/8 inch adapter. When it's threaded on to the blue part, the sending unit is nice and snug. But, 5/8 is too big to fit into the block. I do have a 5/8 inch to 3/8 inch reducer but when all are connected the tip of the sending unit does not extend past the end of the final fitting. This doesn't seem like it should matter to me. But who knows anymore. Here's what all three look like together:

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I'm sure I'm making it much more complicated than it really is but I'm struggling with conflicting absolute answers. It's just a simple fitting into a simple threaded hole. Should be simple but man! I ain't giving up my day job anytime soon.

After tomorrow, who gives a @#$ anymore.

Thanks again.

Rick

Time to answer my own questions:

The Autometer mechanical water temp sending unit DOES bottom out in the aforementioned hole if you try to just use the blue collar. Not even close. In addition, the shoulder does not tighten up properly.

The red 5/8 inch adapter provided with the gauge does NOT fit the block hole. This hole is indeed 3/ inch NPT.

The 5/8 inch to 3/8 inch reducer I showed does fit the block hole just fine. However, when installed like this the temperature gauge never gets above about 170 degrees on a hot engine. I attribute this to the fact the tip of the sending unit does not extent past the end of the adapter. It is recessed by about 1/2 inch. Plus, this set of adapters puts the wire too close to the exhaust manifold for comfort.

So for those of you who told me it is a slam dunk fit in a 2004 4.6L block, either Autometer changed what adapters they provide with their mechanical water temp gauge, the sending unit itself has been changed, you're not installing it in this location, or???

You can't install the sending unit in place of the factory sending unit since the factory sending unit does more than just work the temp gauge in the cluster. A T fitting is not recommended since the factory sending unit is supposed to have coolant flow, not just the presence of coolant, to function properly. I could not get proper gauge readings using a T in this location. The cooling system was purged several times to no avail.

Hopefully Autometer will be able to help from here on out. If anyone is interested, I'll pass along whatever answers I get. MAybe they have a 3/8 inch adapter with 45 degree should to use for the block hole. I certainly can't be the only one who has had this issue, but it sure sounds like it on Stangnet.

Thanks again for your ideas and suggestions.

Rick