Engine temp sensor

[ForceFed70]

If you had to install a 2nd temperature sensor in your car how would you do it?

 

[ttoney]

rectal thermometer in tailpipe? Cruel I know.

 

[shotsy]

you could tap and thread your upper raidiator hose neck or weld a bung into it?

 

[ForceFed70]

you could tap and thread your upper raidiator hose neck or weld a bung into it?

I've been thinking about that, but since it's on the "cold" side of the thermostat I'm worried it won't give the most accurate reading. It won't read true engine temp until the thermostat opens. I guess drilling a small hole in the thermostat might help...

 

[65ShelbyClone]

What I did was put the more accurate Autometer sender in the intake manifold and the stock sender in the thermostat housing. The only way you'll get an inaccurate reading is if you put the t-stat in backward and it never opens.

 

[ForceFed70]

What I did was put the more accurate Autometer sender in the intake manifold and the stock sender in the thermostat housing. The only way you'll get an inaccurate reading is if you put the t-stat in backward and it never opens.

But won't the guage stay pointing at "cold" until the engine has reached operating temp and the thermostat opens...at which point the guage suddenly moves over to "normal"?

 

[65ShelbyClone]

Yeah, but I dont think that would be a problem. I know I wouldnt be real worried if the engine was running cool enough to see the t-stat open and close. If its running too hot, it wont matter since the 'stat will be wide open. The exception would be if it stuck shut and the gage read cold while you were boiling over. If thats a concern, then the thermostat housing wouldnt be the best place for the only gage being used.

 

[ForceFed70]

Yeah, but I dont think that would be a problem. I know I wouldnt be real worried if the engine was running cool enough to see the t-stat open and close. If its running too hot, it wont matter since the 'stat will be wide open. The exception would be if it stuck shut and the gage read cold while you were boiling over. If thats a concern, then the thermostat housing wouldnt be the best place for the only gage being used.

That makes sence. Problem is that I want to use this temp sensor for my EFI conversion so I need to know the engine temp as acurately as possible.

I suppose I could always use the new sensor for the guage and the old one for the EFI computer.

 

[red65]

If you're using the stock 5.0L heater hose outlets: One of the heater hoses connects to a steel tube and 90-deg fitting that screws in near the front passenger-side of the intake manifold. I drilled and tapped the top of that 90-deg fitting to accept a sender for my temp guage (1/8" NPT in my case, but there's room for a bigger fitting if need be). So - the sender screws in vertically into the top of that fitting - take a look - you'll see where I mean. The heater hose is, of course, pre-thermostat, so the temp reading isn't dependent on whether or not it's open. It works well - might be a good place for you if you're using a similar setup...

 

[jbuening]

Some run an extra temp sender in the vacuum port on the thermostat housing. Some of the mustangs had dual vacuum diaphragms and had a fitting on the top of the thermostat housing. Get one of those and you'll be golden, or get an aftermarket aluminum intake. The Typhoon intake i have has three temp sender ports.

 

[D.Hearne]

I always place the second one in the T-stat housing, that way you know when and if the T-stat is functioning.

 

[ForceFed70]

If you're using the stock 5.0L heater hose outlets: One of the heater hoses connects to a steel tube and 90-deg fitting that screws in near the front passenger-side of the intake manifold. I drilled and tapped the top of that 90-deg fitting to accept a sender for my temp guage (1/8" NPT in my case, but there's room for a bigger fitting if need be). So - the sender screws in vertically into the top of that fitting - take a look - you'll see where I mean. The heater hose is, of course, pre-thermostat, so the temp reading isn't dependent on whether or not it's open. It works well - might be a good place for you if you're using a similar setup...

Actually I'm converting my 351W to EFI, but the heater hoses are the same.

I've been considering this... Except instead of drilling and tapping the 90* fitting, I may just swap out the fitting for a "T" style fitting and screw the temp sensor into one end.

Do you happen to know the direction of coolant flow? Some heat will be lost through the heater core so I'd like to be on the "hot side" of the heater core.

 

[ForceFed70]

Some run an extra temp sender in the vacuum port on the thermostat housing. Some of the mustangs had dual vacuum diaphragms and had a fitting on the top of the thermostat housing. Get one of those and you'll be golden, or get an aftermarket aluminum intake. The Typhoon intake i have has three temp sender ports.

Sorry I'm a little confused. Some 5.0's had vacum ports on the thermostat housing? What for?

And if it's a vacum port, why would I put a coolant temp sensor in there?

 

[D.Hearne]

Coolant flows from the intake to the heater, back to the waterpump. Just replace the 90 degree elbow with a Tee fitting.

 

[D.Hearne]

Sorry I'm a little confused. Some 5.0's had vacum ports on the thermostat housing? What for?

And if it's a vacum port, why would I put a coolant temp sensor in there?

That was a vacuum switch on the T-stat housing. The earliest ones switched the vacuum for the distributor ( advance to retard) depending on the engine temp.

 

[ForceFed70]

Coolant flows from the intake to the heater, back to the waterpump. Just replace the 90 degree elbow with a Tee fitting.

Sounds like this is going to be my best route...

 

[65ShelbyClone]

Ok, I didnt know you were doing this for an EFI temp sensor. Thats makes it alot easier.

The EFI cars dont have a water valve going to the heater core, so it gets water circulation all the time. EFI cars have metal heater lines that sit behind the passenger side valve cover. The line feeding the heater core from the intake has a bung in it which it where the stock EFI sensor went! The actual sender for the gage just went in the port on the driver's side rear port of the (EFI)intake.

 

[jbuening]

Sorry I'm a little confused. Some 5.0's had vacum ports on the thermostat housing? What for?

And if it's a vacum port, why would I put a coolant temp sensor in there?

Sorry guess i could have clarified. Some 69/70 (and maybe earlier/later years)302 and 351w motors had the port there. This i guess doesn't help much cause it won't be accurate until the thermostat opens. Just a thought though, as i know some people run the temp guage sender for their factory guage to this port. It still will read coolant temps, but was used i think for advancing/retarding the igntion when the motor was hot. I am not too sure how the port works as far as vacuum goes but i just know people use that port for temp senders.