Removing Temp sensor from Head

[groselle]

I've finally gotten to the point where I can do some serious work on my 1936 special. This weekend I pulled the head to have a peak inside the engine. My biggest problem is how do you remove the temperature sensor from the head. There is a square headed bolt that holds the probe into the head. That came off no problem but I can't figure out how to get the sensor out.

Actually this is more of a "lessons learned" post because I already ended up breaking the tube off in my attempts. So hopefully other can benefit from my misfortune. However, even with the tube broken off I'm still unable to get the sensor piece out of the head.

Thanks in advance.

[Buicksplus]

Gregory:

Welcome to the "honey I broke the temperature sensor" support group. This is a common problem. You have done better than most. I soaked mine for weeks in various solvents and penetrating oils before breaking the tube.

The bulb on the end can be easily replaced by several vendors who advertise in Hemmings. I have used one called "The Temperature Gauge Guy" from Vermont or Florida, and he has done fine work for me at reasonable prices. You need to send him your gauge out of the dash, complete with capillary tube and all the pieces you can find.

You can usually dig the remnants out of the head pretty easily with an easy-out through the hole left by the capillary tube you broke off. Use a large easy-out so you don't risk breaking off the tool inside the bulb. Insert and twist, it will destroy the bulb but should get the remains out of there.

Good luck!

Bill S

Albuquerque, NM

[Guest unclefogey]

Oh, oh, I have been trying to remember what the guy who recommended the rebuilder where I dropped my car yesterday had said what the only item was that had gone wrong with his rebuild. This thread brought it back. It was the temperature sensor! <img src="http://forums.aaca.org/images/graemlins/frown.gif" alt="" /> He was looking for a sensor complete with guage for his '38.

I am going to start a folder to keep everything involved with this rebuild and the first contribution will be the copy of your posting about the "Temperature Guage Guy". Hopefully, I won't need it. After taking the speedometer out for repair, I have acquired a dislike for working on my back with legs over the back of the front seat.

John

[groselle]

Just for everyone's knowledge, I managed to get the temperature sensor out of the head. It should have just pulled straight out once the nut holding it in was removed. However, I guess 70 years on sitting in the cooling jacket got it crusted in. It just took a little wiggling with some needle nose pliers and out it came. Here's a picture of what came out:

36 Temp Sensor

[Guest Captain57]

I have had the same problem back in Jan. when we took our engine apart. The temp. bulb came out of the head about like yours did, but we got it all out in one piece. That is it was still attached to the capillary tube. But in putting it back together and removing it once after that it has come disconnected from the tube. Do you think soldering the two back together would fix it? Probably not as it would affect how the bulb sends the temperature of the engine to the gauge. What do you think? Are there any other solutions for this repair without taking the whole system out of the car and sending it off to be fixed? I need suggestions.

[Guest edalfa]

Unfortunately, this is not a home repair. The bulb and tube are filled with an inert gas that expands and contracts in reaction to heat. To repair this, you must send it to someone who can "refill" it and seal the unit up.

Ed Sheehy

[Fred Rawling]

There was an article in Skinned Knuckels Magazine a few years ago where the author use the bulb from a new theperature sender to repair the old gauge.

He made a copper tube with the same inside diameter as the capilary tube on the temperature gauge, cut the old bulb off the old temp. gauge and soldered the copper tube to the temperature gauge end of the old gauge. Then he put the bulb of the new gauge in dry ice to suck all the gas down into the bulb, cut the new bulb off the new gauge leaving some of the capilary tube on it. He then soldered the new bulb to the tube which was soldered onto the old gauge capilary tube.

The last time I checked, new gauges were around $30.00. I was thinking of buying a used gauge that still worked at the swap meet and trying it out.

[Guest simonmeridew]

I could lay my bulb right on top of your picture: it looks identical to the pic, even broke off at the same place. I think it's filled with ether or other volatile liquid because just after I broke it, a quickly evaporating liquid escaped from the still imbedded bulb and it smelled like ether.

After it broke, I was able to pull the bulb out by grabbing the thin end with a needle nosed pliers and pulling. I think that if I had to do it over again, I could get the thing out without breaking it by reaching in with a needle nose and pulling out straight. While the capillary tube is fragile, the part inside the head is not and that's what you're pulling on. Like everyone else I pulled and wiggled on the capillary tube and broke it. Live and learn.

simonmeridew

[Guest GP Gleason]

Tell me where I can find these new mechanical temp gauges for $30!! I'll buy them all!

You could probably find a "universal" temp gauge for that but an original NOS mechanical temperature gauge would cost between $50-$200 depending on what make it was for.

I would like to find someone to repair all my broken ones. It cost me $80 each to have them repaired at wholesale!

All cases are different but I have used Marvel Mystery Oil soak for 3 days and propane torch to heat the head (or block a little around the sensor has produced great results. I've had only one broken in 40 years!

More later!

[Jamdadbay]

I know this is an old thread, but it was invaluable to me when I've been trying to get my temp sensor out of my 1947 buick straight 8. Was getting very frustrated until I came across this thread. I couldn't move it. Thought I was going to break it, couldn't grab the back end of the bulb. Then I sprayed it and sprayed it with inox and went and brought a cheapy tiny locking pliers. Came back 2 days after spraying and still couldn't move it. I locked the small pliers onto the back of the bulb connection and trapped it with a hammer and rotated until it started to move. Finally came out all in one piece. Awesome. Thanks for the tips guys. 

[Ben Bruce aka First Born]

1 hour ago, Jamdadbay said:

I know this is an old thread, but it was invaluable to me when I've been trying to get my temp sensor out of my 1947 buick straight 8. Was getting very frustrated until I came across this thread. I couldn't move it. Thought I was going to break it, couldn't grab the back end of the bulb. Then I sprayed it and sprayed it with inox and went and brought a cheapy tiny locking pliers. Came back 2 days after spraying and still couldn't move it. I locked the small pliers onto the back of the bulb connection and trapped it with a hammer and rotated until it started to move. Finally came out all in one piece. Awesome. Thanks for the tips guys. 

 

 

  Thank you.

  As Jamdadbay said an old thread. 

 

  Listen up!

 

  THE BOLT HOLES FOR THE DISTRIBUTOR SIDE OF THE ROCKER ARM STANDS ARE THROUGH HOLES.  REASON FOR OIL ON THE PLUGS.  THE ONE FOR THE LAST STAND IS ABOVE THE COOLANT TEMP SENSOR.  OFTEN, SOMEONE HAS INSTALLED A BOLT/STUD THAT IS TOO LONG AND THIS ONE CONTACTS THE SENSOR. REMOVE THAT BOLT IF HAVING TROUBLE REMOVING THE SENSOR.

 

 Having this bolt removed allows penetrate to be applied directly on the sensor.

 

  Try it, you will like it.

 

  Ben

[Fr. Buick]

Would that bolt hole give a little access to the back of the sensor to wiggle it loose from behind?

[Kenneth Carr]

I struggled with that sensor on my ‘41. It took me days to remove after I broke the cable off (unintentionally). The full story along with a few other challenges is here: http://idlenot.com/ 

I eventually bought an NOS unit from a friend. It works great!