Installing an aftermarket temperature gauge

[6R9Runner]

Well I opened up a can of worms today. The lower rad hose was very old, so I drained the rad and set about to trim the replacement, only to realize it did not have a support spring inside. I managed to fish one in and that went smoothly. With the rad drained it made sense to fix the seepage around the top neck gasket. That's when I discovered there was no thermostat. Since the dash temp gauge is not working, I figured it was also time to install an aftermarket gauge.

Getting to the point, HOW DO I GET THE PLUG OUT OF THE TOP OF THE WATER PUMP? That looks like the obvious place to install the sender tip. It has a 3/8" square recesss which accepts a 3/8 extension, but its in there good! What's the safest way to remove that plug? Is there a danger of cracking the housing if I crank the plug too hard?

 

[droptop]

I would like to hear some other ideas also. I have one in the 300 that I have tried to get out and only managed to break tools.

 

[John69RR]

Since the housing is cast you need to be careful. Soak the plug with something like PB Blaster. Then try using an impact driver. This is a hand held tool that you hit with a hammer to loosen frozen fasteners, plugs, etc... The jarring of the hit will often break loose the rust. Here is a link to Sears but I'm sure harbor Freight or Northern Tool sell them also.
http://www.sears.com/shc/s/p_10153_12605_00947641000P

 

[6R9Runner]

Since the housing is cast you need to be careful. Soak the plug with something like PB Blaster. Then try using an impact driver. This is a hand held tool that you hit with a hammer to loosen frozen fasteners, plugs, etc... The jarring of the hit will often break loose the rust. Here is a link to Sears but I'm sure harbor Freight or Northern Tool sell them also.
http://www.sears.com/shc/s/p_10153_12605_00947641000P

Thanks for the lead- I'll track one down and give it a try.

 

[ACME A12]

I know you'd have to bust out the engine enamel after you were done, but what about the mild application of the red wrench on the housing around the plug? Just a thought...

 

[69hemibeep]

And remember a 50-50 mix of acetone and ATF works twice as good as PB blaster so the study showed

 

[6R9Runner]

Thanks for the great ideas- between impact, heat, acetone and ATF something should budge.

 

[SomeCarGuy]

Might try the old candle wax trick on it. Wax works into the threads and forces out the corrosion and gunk. Then it turns easily.

 

[a6t9vette]

Not related to getting the old plug out, but thought Id post this to show how/where I ran the "wire" for my aftermarket temp sensor. Ironically, after I put a new sensor in for the guage in the dash Just to plug the hole and have a place to terminate the wire running to it, it started working again, so now I have 2 temp guages.

 

[Big John]

This is just a thought, but without a thermostat, the engine will run pretty cold. Possibly too cold to show on the temp gage. Again... just a thought.

I'd break out teh old blue tip wrench and sneak up on it a little, not getting it too hot. They do make square sockets too. Its probably worth picking one up for this. Its a pipe thread, so its tapered and once its loose itshould back right out.

 

[6R9Runner]

The edges of the plug are soaking in 50:50 acetone/ATF right now so tonight will be the test. If it doesn't budge then I'll hit it with some heat. Thanks again for the ideas- at least I don't feel stuck anymore.

 

[6R9Runner]

Not related to getting the old plug out, but thought Id post this to show how/where I ran the "wire" for my aftermarket temp sensor. Ironically, after I put a new sensor in for the guage in the dash Just to plug the hole and have a place to terminate the wire running to it, it started working again, so now I have 2 temp guages.

THAT is a NICE JOB! The passenger side of my engine is getting a little busy- I like it. :worship:

 

[6R9Runner]

This is just a thought, but without a thermostat, the engine will run pretty cold. Possibly too cold to show on the temp gage. Again... just a thought.

I'd break out teh old blue tip wrench and sneak up on it a little, not getting it too hot. They do make square sockets too. Its probably worth picking one up for this. Its a pipe thread, so its tapered and once its loose itshould back right out.

Hmmmm. Now I want to trace that purple wire under the dash and see if its even plugged in... :loco:

8/03 I shorted the purple wire to ground and the gauge does not budge. That method worked on the fuel gauge so I guess either the wire is disconnected behind the instrument panel or the gauge is crap. But now I have a temp gauge so no worries...

 

[6R9Runner]

The plug is finally out- here's what worked:

DAY 1
1) 24" ratchet with 3/8 extension (this felt wrong- too much torque for this tool)

DAY 2
2) wire-wheel to remove paint
3) nail to scrape into edges around plug
4) 50:50 mix of ATF:acetone applied several times morning and night

DAY 3
5) impact driver (great tool)

DAY 4
6) 24" Proto breaker bar with adapter and 3/8 extension

4 and 5 likely loosened it up enough for the bar to crack it free. Drain plug sockets would have been the 100% correct thing to use as the plug head was distorting, and heat was next on the list but i got lucky. Great advice, thanks again.

 

[69hemibeep]

good to hear :yesnod:

 

[6R9Runner]

The temp gauge is in and functioning, now all I have to contend with is a leaking water pump neck. I was careful to scuff off any corrosion on the mating surfaces, clean with acetone, then apply black RTV according to directions. It started weeping front and back at the midpoint after it cooled down, but not near the bolt holes. My guess is the neck is warped and I sure wish I had noticed before buttoning it all up...

update 8/02 ...guess again. It turns out the darned blue paper gasket was weeping. Maybe by using black high-temp RTV on either side that affected the gasket compression? Anyhow I cleaned it all off, flat-filed the neck and pump flanges to ensure flatness, wire-wheeled off any pits or surface corrosion, cleaned with acetone and then used the gray RTV silicone designed for water pumps. 24 hrs should tell if it worked. :brickwall:

 

[John69RR]

Thats good news. Glad to hear nothing broke.

 

[Basketcase]

good to hear. the only housing I ever had leak was the chrome one that was one the car when I got it. chucked it and put a stocker on.

 

[6R9Runner]

good to hear. the only housing I ever had leak was the chrome one that was one the car when I got it. chucked it and put a stocker on.

I wonder if anyone has been successful with the chrome necks- and what they did to make them work? Maybe its a big secret and they're all having a good laugh. When they fail, either the flange warps from over-tightening or the chrome peels off? Anyhow my setup with the water pump RTV and no gasket passed the test with the engine up to temperature. I appreciate the input and ideas once again.

 

[george68hemirr]

i found out that when using atv you only apply it to one side of the gasket if using a gasket.....glad to hear you got through your problem