I need some advice...

[Ickaber]

My temperature gauge hasn't worked since I bought my '63. So, between my shop manual and the numerous threads on here regarding the gauges, I determined that I needed a new temperature sender. I found that my local Napa had them for cheap ($7.50) so bought one on Saturday.

To keep a long story short, upon installation of the new one, I snapped it off. So I then essentially had a plug. I tried to use one of those tools for removing stripped screws, but it wouldn't turn out. All it did was chip/flake away what was left of the sender. I believe I could keep doing that and clear the threads, but the problem, of course, is that if I keep doing that, at some point I'm going to lose those chips and the bottom of the sender down into the coolant below. I believe the sender is made of brass, which is 1) why it breaks out so easily, and 2) I can't use a magnet to pull those chips out as I go.

So I need some advice from all of your collective experience. How do I finish getting the bottom of the sender out?

As an FYI, when I bought the sender, it came wrapped in what I think is plumber's tape, which I left on, and I think it was too much which caused it to go in too tightly. Consequently, the threads don't turn to come back out. The old one didn't have any when I took it out, and if I ever get this one out, the new one I put in won't have any either.

Thanks as always.

Scott

[simplyconnected]

Here's one suggestion: Take your Thermostat off. If you can see the bottom of the old Temp Sender, stick some rags passed it and let the chips fall with the rag in there. When done, gently pull the rag out. After you're done and the Thermostat is still out, run a garden hose down that Temp Sending hole and let the water flow carry any chips out the Thermostat hole. To keep water flowing in one direction, simply put your hand over the Surge Tank hole while doing the garden hose thing.

IMPORTANT*** The Temp Sending Unit requires a good ground. Keep all Teflon tape away from the threads so it can conduct six volts back to ground. Your cooling system operates below ten psi. There is no need for a lot of 'help' on pipe threads to seal. - Dave

[Ickaber]

Thanks Dave! I'll give that a shot and let you know how it goes.

After pondering this for the last 2 days, I've come to the conclusion that the tape was probably on there more to protect the soft brass threads than anything else, and your comments seem to support that.

[Ickaber]

Dave, thanks for the suggestion. By going in the thermostat hole I was able to put a rag there and catch all of the shavings as you suggested. I learned during this process that if you use part of a microfiber towel as your rag, that stuff catches and holds on to everything.

Now I have a new question on this. The new temp sender was also wrapped in teflon tape, although not as thickly. I removed it all. But, when putting the new temp sender in, it's still going in pretty hard. I've threaded it in and out a bunch of times, thinking maybe there was something left in the threads from the last one. This is taking the sharp edges off the threads of the temp sender.

I've gotten it down as far as having all of the threads in, but it's gotten really hard to turn, so I stopped since continuing on is how I broke the last one.

So my question is, do these need to be seated all the way down, or are they supposed to be up a little bit? What makes me wonder is that the threads don't run all the way up.

Below is a pic of where I stopped turning, and you can see that the hex part of the temp sender is above the intake manifold by about 1/2", but that there are no more threads directly under the hex part. Am I okay to stop here and leave it as is, or does it need to be seated down further?

[Yadkin]

As far as I know those are standard NPT threads, which are tapered. The female in the iron is tapered, and the male fitting is tapered, so the more you tighten it down, the tighter the assembly gets.

There is no standard torque values for these type of threads. You just have to go by feel. Keep in mind that you're only holding back 15psi, so you don't need to crank down on this. Usually finger tight plus one full turn is all you need.

No matter how much you tighten, the assembly still needs a sealant to prevent a leak. The leak occurs between the crest of the male thread and the valley of the female.

You are better off using a thicker layer of teflon than over-tightening. Plumbers like to use brush-on teflon because it squeezes out between the teeth and flows into the valley. Car guys like to use tape because it's neater, but it requires more pressure to make the tape "flow" to where it's needed.

Nice color blue on the manifold. It looks like powder coat.

[Ickaber]

As far as I know those are standard NPT threads, which are tapered. The female in the iron is tapered, and the male fitting is tapered, so the more you tighten it down, the tighter the assembly gets.

Well that explains a lot.

No matter how much you tighten, the assembly still needs a sealant to prevent a leak. The leak occurs between the crest of the male thread and the valley of the female.

You are better off using a thicker layer of teflon than over-tightening. Plumbers like to use brush-on teflon because it squeezes out between the teeth and flows into the valley. Car guys like to use tape because it's neater, but it requires more pressure to make the tape "flow" to where it's needed.

The old one I took out didn't have any tape (or anything else that I could see), and per Dave there shouldn't be teflon on these as they need to ground to the engine.

Nice color blue on the manifold. It looks like powder coat.

Thanks. It was like that when I bought it. I think it's just paint, though.

Well, I did some more looking and I can see the bottom of the sender is down in there, so I think I'm going to put it all back together and see how it does. If I get a leak there, maybe I'll throw a little teflon at it, but I'm going to try without it first.

Thanks for the help, and I'll let you know how it goes.

Scott

[simplyconnected]

...No matter how much you tighten, the assembly still needs a sealant to prevent a leak...

...I think I'm going to put it all back together and see how it does. If I get a leak there, maybe I'll throw a little teflon at it, but I'm going to try without it first...

Ok, so now we have a balancing act. The threads need to be sealed but only a small amount of insulation will hold back six volts.

I would (as instructed by the book) screw the dry sender in the tapered hole and tighten it. Since these are tapered threads, there is no set rotation. Tighten it passed 'snug'. It should take a fair amount of wrench pressure to loosen it then see if it leaks. If you are looking to lubricate the threads, use oil. Anti-seize works well and it is made from conductive aluminum.

The same holds true for your 6 volt oil pressure sending unit. It too is a tapered thread that requires no Teflon. I'm not opposed to using Teflon but it has its place. Tape holds together well but excess paste will wash off. Plumbers use Teflon paste on gas lines to prevent those little strings from clogging the gas valve (and holding it open). If an inspector sees Teflon tape on a gas pipe he will knock it down, for sure. For normal water pipe threads, Plumbers use either tape or paste, which ever they pull from the tool box first.

I use Teflon tape and rubber caps on my bleeder screws. I use Teflon tape on steel brake line, just under the flare fitting. Both keep moisture out. Teflon is a non-stick lubricant that ensures your threads will come apart easily because it keeps the metals apart.

It's ok if your sending unit sticks up. It should NOT go down to the hex. - Dave

[Yadkin]

My mistake, not thinking about the electrical connection, the threads of the fitting using the manifold as a ground.

Since that is the case, I'd suggest using a small amount of paste sealant on the treads. It will squeeze out, allowing metal-to-metal contact.