Cool/Heat: Stuck temp sender

[3rdGenStude]

Last night I tried to remove the temp sender from my '62 289. After driving only three miles it's registering 240 degrees on the gauge but showing no signs of boiling or steam. I'm guessing it's about a 50/50 chance of being either the sender or the gauge. I thought the sender would be the easier of the two to work with. (GT Hawk dash doesn't look welcoming to take apart.)

I got a good solid grip on the sender with an open end 5/8" wrench, but couldn't turn the sender out of the block. I even tried tightening it a bit more to budge it loose, but no go.

How much torquing can that little piece of brass take without snapping apart or rounding? I don't want to make things even worse. Is there an easier way to get the sender out? Is it more accessible from underneath?

Paul

[1954khardtop]

Try again with a box end wrench, longest one you have, and don't be shy about it. It's a tapered pipe thread, and will loosen quickly as it starts to turn. It's in a plate that's only 1/4" thick or so, and probably has a buildup of corrosion on the back side. Worst thing that can happen is the sender breaks. If that happens just unbolt the plate (2 bolts) from the head and work on it on the bench.

[JoeHall]

To test the sender, simply unplug it, and tape the wire's connector so it does not accidentally go to ground. If your gauge then stops pegging, its likely the sender. If not, most likely wiring or the gauge. On a GT, the wire slips right off the, "tit" on the end of the sender. Do not even need a wrench, but best done when the motor is cool.

[Daytona]

Like he said a long box end wrench then I take my hammer and hit the wrench it seems to loosen a nut .

[3rdGenStude]

Thanks all for the info. I didn't know it was on a plate. Sounds similar to the block off plate I have on the right side head since taking the heater hoses off for now. (originally an air-conditioned car) I'll try to be a little more "persuasive" next time I get in there.

Paul

[3rdGenStude]

I looked in the shop manual and found that the recommended procedure is to take the whole plate off.

BTW, did Studebaker dealers hire children with small hands to get into some of these places to work?

I got the two bolts out but had to "persuade" the plate to come off. (don't even ask how long it took to fish it out from between the engine and firewall. Finally got it by getting the car up on jack stands and getting it from below, answering my own question about whether or not it is easier to get at this from underneath. It isn't.)

Finally got the plate and sending unit in the vise. It took some long hard swings with a small sledge against the wrench to break the sending unit free from the plate. The steel mounting plate is actually gauged out by the base of the sending unit, it was in so tight. My sender from SI should be here today or tomorrow.

Anybody want to loan me a skilled child to put it back in?

Paul

[karterfred88]

A six point box wrench, or deep 6 point socket, is best, tap it with a hammer a few times, in the direction to loosen, then reverse tapping to tighten, then whack it hard in the loosen direction. Should break the rust/goo loose. Once it starts it will come out easy. Put pipe sealant on the new one, its an NPD thread and may leak without it. Have fun, and as said, worst case you can remove the block off plate it's installed in if necessary, but you loose the leverage you get while attached to the head.

[63 R2 Hawk]

I use anti-seize copper bearing compound on the sending unit and clean the threads really good. The sender requires a good ground to get an accurate reading and I've had problems with pipe dope and Teflon tape causing poor grounds.

[3rdGenStude]

I use anti-seize copper bearing compound on the sending unit and clean the threads really good. The sender requires a good ground to get an accurate reading and I've had problems with pipe dope and Teflon tape causing poor grounds.

I wondered about that. Is this available at a GOOD auto parts store or hardwdare store?

Paul

[karterfred88]

A quick tip to help install, remove the nuts under the transmission mounts at the cross member, floor jack under the tail shaft, and raise it slightly. It will give your fingers some room between the head and firewall. Don't forget to put them back on!!!

[JoeHall]

I looked in the shop manual and found that the recommended procedure is to take the whole plate off.

BTW, did Studebaker dealers hire children with small hands to get into some of these places to work?

I got the two bolts out but had to "persuade" the plate to come off. (don't even ask how long it took to fish it out from between the engine and firewall. Finally got it by getting the car up on jack stands and getting it from below, answering my own question about whether or not it is easier to get at this from underneath. It isn't.)

Finally got the plate and sending unit in the vise. It took some long hard swings with a small sledge against the wrench to break the sending unit free from the plate. The steel mounting plate is actually gauged out by the base of the sending unit, it was in so tight. My sender from SI should be here today or tomorrow.

Anybody want to loan me a skilled child to put it back in?

Paul

If clearance for the sender is that close on your GT, you have some seriously sagging mounts or something. Even on 56Js (same location) they are not as close as yours sound to be.

[3rdGenStude]

Update:
I got the new temperature sender mounted, remounted the leaking block off plate on the right hand head, and put a new thermostat in right away too, as long as I had to refill the coolant anyway. The good news is:
No more leaks, including no oil leaks from the rocker covers (refinished and re-gasket-ed)
I have reassurance that it's not overheating.
The bad news:
The gauge still reads 240+ at operating temp. I let it run up to "240" with the radiator cap off and stuck a cooking thermometer into the radiator. The cooking thermometer showed about 170 degrees F while the gauge said 240. For added peace of mind I think I'll take the thermostat out altogether.

Thanks again for all the hints.

Paul

[karterfred88]

s

Update:
I got the new temperature sender mounted, remounted the leaking block off plate on the right hand head, and put a new thermostat in right away too, as long as I had to refill the coolant anyway. The good news is:
No more leaks, including no oil leaks from the rocker covers (refinished and re-gasket-ed)
I have reassurance that it's not overheating.
The bad news:
The gauge still reads 240+ at operating temp. I let it run up to "240" with the radiator cap off and stuck a cooking thermometer into the radiator. The cooking thermometer showed about 170 degrees F while the gauge said 240. For added peace of mind I think I'll take the thermostat out altogether.

Thanks again for all the hints.

Paul

Leave the thermostat in. It acts as a flow restrictor to control flow-too fast and it may run HOTTER. If you show 170 in the radiator tank you are way safe. Did you get the sender from a Stude vendor or elsewhere? What does the gauge do with key in ACC position, cold after sitting for 5-10 minutes? If it still reads 240 engine not running-and cold you have a short to ground in the sender wire. If it stays low until engine warms up and slowly goes to 240 and stays there, wrong sender. S-W temp gauges have multiple sender ranges, need to be gauge matched. No generics or "all-purpose" here. You can use a multi-meter to find the voltage necessary to read 170. The gauge "sweep" is designed to match the senders resistance range. If you get one for a 90 degree sweep and your gauge only sweeps 60 it will peg while still cool. Since the original gauge is an "antigue" not currently produced getting a matching sender can be a pain.

[3rdGenStude]

s
Leave the thermostat in. It acts as a flow restrictor to control flow-too fast and it may run HOTTER. If you show 170 in the radiator tank you are way safe. Did you get the sender from a Stude vendor or elsewhere? What does the gauge do with key in ACC position, cold after sitting for 5-10 minutes? If it still reads 240 engine not running-and cold you have a short to ground in the sender wire. If it stays low until engine warms up and slowly goes to 240 and stays there, wrong sender. S-W temp gauges have multiple sender ranges, need to be gauge matched. No generics or "all-purpose" here. You can use a multi-meter to find the voltage necessary to read 170. The gauge "sweep" is designed to match the senders resistance range. If you get one for a 90 degree sweep and your gauge only sweeps 60 it will peg while still cool. Since the original gauge is an "antigue" not currently produced getting a matching sender can be a pain.

OK on the thermostat. Saves me some time then anyway.

I got the new sender from SI. Physically, it was a little longer than the old one, but I figure SI would supply the right one. Rock Auto listed a Standard and an Airtex for less than half of what SI charges for the sender, but I thought I'd play it safe.

If I put the ign. switch in ACC position, the temp gauge doesn't move if the engine is cool. When I took it out for a drive yesterday it warmed up gradually, hung around 180 for a little while, and then moved up to 240+. This is the same behavior I had with the old sender, too.

Paul

[rstrasser]

If the water temperature is 170 degrees and the gauge with its sender in the back of the cylinder head reads 240 degrees ; there are only two possibilities. The gauge is wrong or the water is not circulating to the back of the cylinder hear.
You could go to a auto parts store and purchase another temperature gauge and sender and install it in the location of the present sender. Or you could go to Home Depot and purchase a 60 dollar Klein Infrared Scanner and scan the sender location and the radiator etc. Easy enough to test the accuracy of the scanner. Scan metal in ice water and scan metal in boiling water. You could also test your present gauge and sender by placing the sender in boiling water.
Ron