Water Temp sender in water pump - 351C

TheDude

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Hey guys, this seems like a dumb question, but I've wasted a bunch of time on this little thing so figured I'd try and waste your time as well.

I'm trying to add a second temp sender on my 351C. The first one in the stock location is currently being used for the electric fan. So I need a 2nd location for the actual gauge. There is an inlet is currently capped on the water pump itself just below the heater connection. Seems like a logical choice but the sender doesn't fit in that spot. Bought a bunch of adapters locally and online and they are all the wrong size. Does someone know what adapter I need to use to get the stock sender in that location? 

Sorry to waste time on such a little thing, but been screwing around with this for a couple weeks now and just want to get this done as it's holding up a bunch of other stuff for me so thought I'd ask. 

Thanks

 

rackerm

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Hey guys, this seems like a dumb question, but I've wasted a bunch of time on this little thing so figured I'd try and waste your time as well.

I'm trying to add a second temp sender on my 351C. The first one in the stock location is currently being used for the electric fan. So I need a 2nd location for the actual gauge. There is an inlet is currently capped on the water pump itself just below the heater connection. Seems like a logical choice but the sender doesn't fit in that spot. Bought a bunch of adapters locally and online and they are all the wrong size. Does someone know what adapter I need to use to get the stock sender in that location? 

Sorry to waste time on such a little thing, but been screwing around with this for a couple weeks now and just want to get this done as it's holding up a bunch of other stuff for me so thought I'd ask. 

Thanks
You might want to conside finding 1974 - 1976 FORD CAR TRUCK 351M 400 THERMOSTAT HOUSING D5AZ-8592-A. It will fit a 351C and has threaded ports for such things as a temp sender or PVS vacum switch. Best to put your temp sensor as close to your thermostat as possible.





 

Don C

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The water pump pulls water out of the radiator and pumps it through the engine, so a temperature sensor at that location will give you the cooled water temperature, not the engine temperature.

Rackerm's solution is best.

 

Don C

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Thermostat housings from some 460s also have 2 threaded holes, but the are angled and may require upper hose modifications.

 
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TheDude

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Thanks for the feedback. I actually just installed a new aluminum housing and would like to keep it if I can. The pick you uploaded looks like it has a sender in the location I am talking about. Having trouble figuring out what thread that is for some reason or at least the couple of sending units I've had so far and all the adapters are different. 



I've seen a lot of people use these adapters to sit on the top radiator hose. Seems like people are generally happy with them, however it seems like it has the same issue of being on the wrong side of the thermostat and I'm nut a huge fan of having more places for things to leak. Thoughts on something like this?



 
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Don C

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You are correct, they're on the wrong side of the thermostat and will only start showing temperature after the thermostat opens. The water pump location at least has the heater bypass to show the temperature of the engine warming up, but, if you have the bypass plate and 351C thermostat it will just show the temperature after the coolant passes through the radiator after the thermostat opens.

I believe the plug on the side of the water pump is 3/8" pipe thread.

 
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SteveO_71

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Dude, I actually went thru this exercise recently since I wanted the factory temp gauge in addition to a "real" gauge. The factory sender was kept installed in its original location and the other npt connection on the water pump was occupied with the DVCV.

I ended up using a heater hose adapter from autometer. It needs a ground wire run to the engine and its placed in the hose going "to" the heater core. The return heater core hose was a few degrees cooler so doublecheck with an IR gun if not sure which hose is hotter.

Seems to work fine with the autometer temp gauge and the numbered reading matches what I was seeing with the factory gauge. Also nice in that it can be hidden under the frame support member so its not as noticeable as being in the radiator hose.

https://www.autometer.com/5-8-heater-hose-adapter.html

View attachment 41731

 
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TheDude

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I like that option, but unfortunately I'm not running a heater at the moment. I'll look into swapping out the housing for the 351M style as that does look to be the cleanest options.

Thanks

 

Don C

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You don't have to have a heater, just loop the heater hose from the outlet on the block to the inlet in the water pump and install the adapter in the looped hose.

 

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You can also tap the heater port with an NPT thread and connect the sender. Once you tap with NPT you will have access to all kind of adapters. I tapped mine and added an adapter with a 5/8 barbs for the heater hose. This is a good idea. I think i could find a way to connect the sender to the adapter.

Sent from my SAMSUNG-SM-G930A using Tapatalk

 

TheDude

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Thanks Don. I do have the bypass hose, it's just very short and mostly curved so not sure this adapter will fit in that spot very cleanly. That and it's $40+.

Tony, interesting idea, I'll think about that.

Going back to my original question, if the heater hose is OK, what about the DVCV port I looking at on the water pump? Not sure about the water flow, but if I'm not mistaken that should get engine temp water all the time regardless of the thermostat or am I mistaken? While not right at the block, it's very close and it seems like it should show pretty close to engine temp. I am hooking this to the stock engine temp gauge which doesn't actually have numbers on it. Seems like if it's close to engine temp and will let me know if I am getting a big increase that it might be fine.

 

Don C

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I looked at brass fittings from Lowe's, and I could build one for less than $25, wouldn't look as slick, but be functional.

Tony's idea is also a good one, and would look better than an adapter hanging on the hose. It's also a good idea to remove the pressed in hose connection and tap it for a screw-in connection, get rid of the thin-walled prone to rust out connector.

 
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tony-muscle

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So I was thinking a little more about this. I couldn't verify, but I think the NPT thread would be 3/8" on the block end. You could add a "street" tee fitting that has a male end and two females (such as https://www.ebay.com/itm/Brass-Pipe-Street-Tee-Fitting-3-8-NPT-Air-Water-Fuel-/271374668060). The male would be threaded into the block. The middle connection would be a female NPT where you would thread the sender. On the other female end, if you are using the heater hoses, you will thread a fitting with a 5/8 hose barb (such as https://www.ebay.com/itm/3-8-NPT-to-5-8-625-Hose-barb-Adapter-Fitting-Bare-Aluminum/223471373682?hash=item3407ee8d72:g:Fo4AAOSwiDpbFsDM). I think i would try this idea sometime down the road so I can relocate my sending unit to read before thermostat temperature. I now have the EFI sensor in the OEM location and the gauge on the after-thermostat location, which always read low.

 
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Don C

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I have a stripped down block hanging on the engine stand, I'll verify the size needed today.

 

rackerm

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In 1973 Ford used an H-pipe spliced into the heater hoses. I had it on my car but I replaced it with the 351M thermostat housing with the ports I mentioned earlier.





 
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Don C

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Tapping the hose connection on the block will require a 3/8" NPT tap.

 

SteveO_71

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What would be the purpose of having the H pipe in the heater hoses? Although it does create an additional npt port. Was this only used on the 73's?

 
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rackerm

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What would be the purpose of having the H pipe in the heater hoses? Although it does create an additional npt port. Was this only used on the 73's?
You got it. That is all it was for. I think is was only on 73 and 74 (ie Torinos, etc) years and I have only seen it on 351Cs, but it may have been used on other engines.

 
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