The Ford Barn

Model51 · 01-08-2026, 06:27 PM

Is there any sealant needed for the threads of the nut that holds the temperature sensor in the water pump? The nut seems like straight threads and not pipe threads and there's a lip on the top of the sensor that the nut appears to press against. I'm assuming the sensor and nut don't require any sealant, but I'd rather do it right the first time. The engine is for a stock 1935 Ford and I've attached an image of the sensor and nut only part way installed in the water pump.

Ernstudet22 · 01-09-2026, 01:31 AM

Since the wire goes through the nut, the probe has to seal on the taper. Make sure the seat is clean and smooth.

Brian · 01-09-2026, 03:24 AM

i always use a generous amount of anti seize compound on the seat of the bulb and the nut, and just 'nip' up the nut sufficient to stop coolant from weeping out. Next time you got to remove the sender unit, you'll be glad you did it that way. So many of the capillary tubes have been wrecked over the years because people have just assembled dry and really cranked down the nut.

petehoovie · 01-09-2026, 11:23 AM

Quote:

Originally Posted by Model51

Is there any sealant needed for the threads of the nut that holds the temperature sensor in the water pump? The nut seems like straight threads and not pipe threads and there's a lip on the top of the sensor that the nut appears to press against. I'm assuming the sensor and nut don't require any sealant, but I'd rather do it right the first time. The engine is for a stock 1935 Ford and I've attached an image of the sensor and nut only part way installed in the water pump.

Kube · 01-09-2026, 11:38 AM

Quote:

Originally Posted by Brian

i always use a generous amount of anti seize compound on the seat of the bulb and the nut, and just 'nip' up the nut sufficient to stop coolant from weeping out. Next time you got to remove the sender unit, you'll be glad you did it that way. So many of the capillary tubes have been wrecked over the years because people have just assembled dry and really cranked down the nut.

You are 100% spot on with your advice!

Model51 · 01-09-2026, 04:22 PM

Sponsored Links (Register now to hide all advertisements)

Thanks for the advise and explanation. I'll definitely put some anti-seize compound between the nut and the sender.

Brian · 01-09-2026, 06:56 PM

And just nip up the nut sufficient to prevent weeping at the nut; don't go gorilla!!

01-09-2026, 01:31 AM	#2
Ernstudet22 Junior Member Join Date: Nov 2018 Posts: 21	Re: Water pump temperature bulb sealant Since the wire goes through the nut, the probe has to seal on the taper. Make sure the seat is clean and smooth.

01-09-2026, 03:24 AM	#3
Brian Senior Member Join Date: May 2010 Location: Masterton, New Zealand Posts: 4,097	Re: Water pump temperature bulb sealant i always use a generous amount of anti seize compound on the seat of the bulb and the nut, and just 'nip' up the nut sufficient to stop coolant from weeping out. Next time you got to remove the sender unit, you'll be glad you did it that way. So many of the capillary tubes have been wrecked over the years because people have just assembled dry and really cranked down the nut. __________________ Unfortunately, two half wits don't make a whole wit!

01-09-2026, 04:22 PM	#6
Model51 Senior Member Join Date: May 2010 Location: Fairfax Station, VA Posts: 934	Re: Water pump temperature bulb sealant Sponsored Links (Register now to hide all advertisements) Thanks for the advise and explanation. I'll definitely put some anti-seize compound between the nut and the sender. __________________ 1935 157" 1 1/2 ton stake truck undergoing full original restoration 1936 131 1/2" panel truck rescue preservation Author of the 1935-1936 Ford Model 51 V8 Truck book published by the Early Ford V8 Club of America

01-09-2026, 06:56 PM	#7
Brian Senior Member Join Date: May 2010 Location: Masterton, New Zealand Posts: 4,097	Re: Water pump temperature bulb sealant And just nip up the nut sufficient to prevent weeping at the nut; don't go gorilla!! __________________ Unfortunately, two half wits don't make a whole wit!