MGB Stuck water temperature sensor

[Aussie Chris]

I have a 1974 Mgb and trying to remove dual water temp and oil pressure gauge. I removed the nut holding the sensor just under the thermostat housing but the unit will not come out and I don’t want to force in case breaking the tubing going to the gauge. So far have move it a bit sprayed with wd40 but no go would still having the system full of fluid create suction to stop it coming out no water has come past the sensor .
Also would taking out the thermostat give me access to the sensor ? The engine it self has just been rebuilt and working fine initially I had issues with blowing welsh plugs but this was due to wrong pressure radiator cap it took three plugs to find this out .
If anybody could give me some idea how to tackle this issue it would be much appreciated

Regards
Aussie Chris

 

[DrEntropy]

Welcome, Chris!

It sticks into the well the thermostat sits in and can be ~coaxed~ out with aid of a flat screwdriver, but use caution. And the steel collar on the outside around the coil/tube is not connected to the ether bulb, so twisting that doesn't do much of anything to loosen the bulb. It can aid in pulling it out once it moves after some fussing through the t-stat housing, though.

 

[DrEntropy]

And a moderator or the Boss will likely move your post to the MG section where it will get more marque specific eyeballs.

 

[Aussie Chris]

Welcome, Chris!

It sticks into the well the thermostat sits in and can be ~coaxed~ out with aid of a flat screwdriver, but use caution. And the steel collar on the outside around the coil/tube is not connected to the ether bulb, so twisting that doesn't do much of anything to loosen the bulb. It can aid in pulling it out once it moves after some fussing through the t-stat housing, though.

 

[Aussie Chris]

Thanks a lot much appreciated
Aussie Chris

 

[Aussie Chris]

And a moderator or the Boss will likely move your post to the MG section where it will get more marque specific eyeballs.

Welcome, Chris!

It sticks into the well the thermostat sits in and can be ~coaxed~ out with aid of a flat screwdriver, but use caution. And the steel collar on the outside around the coil/tube is not connected to the ether bulb, so twisting that doesn't do much of anything to loosen the bulb. It can aid in pulling it out once it moves after some fussing through the t-stat housing, though.

DrEntropy,
Thanks for your info two questions.
1. can you actually get to the sensor from the thermostat housing?

2. Do I need to lower water in the system to below the sensor?

Regards
Aussie Chris

 

[DrEntropy]

Thanks for your info two questions.
1. can you actually get to the sensor from the thermostat housing?

2. Do I need to lower water in the system to below the sensor?

Yes to both questions. You can easily see the sensor protruding into the chamber underneath the thermostat once it is removed. At least half of the coolant should be drained to easily see and push on the sensor. Use a flat piece of wood between any metal prying tool and sensor so you do not damage that bulb.

 

[Aussie Chris]

Yes to both questions. You can easily see the sensor protruding into the chamber underneath the thermostat once it is removed. At least half of the coolant should be drained to easily see and push on the sensor. Use a flat piece of wood between any metal prying tool and sensor so you do not damage that bulb.

DrEntropy,
Yet again thank you so much for the great advice,I am in Melbourne Australia at the moment but will be heading home on the weekend .
Home is a little place called Indented Head on Port Phillip Bay population about 1000. I will try getting it out then.
The price for a new unit is $210 Australian but spares are scarce at the moment. The reason for taking it out is I want to remove dash to respray, everything else is out except this gauge . It was all started with replacing floor coverings which led to repair of the floor, insulation installed, interior led light conversion and so it goes on. This is my first venture into restoring not looking for concourse but something that is reliable .

King Regards
Chris

 

[DrEntropy]

DrEntropy,
Yet again thank you so much for the great advice,I am in Melbourne Australia at the moment but will be heading home on the weekend .
Home is a little place called Indented Head on Port Phillip Bay population about 1000. I will try getting it out then.
The price for a new unit is $210 Australian but spares are scarce at the moment. The reason for taking it out is I want to remove dash to respray, everything else is out except this gauge . It was all started with replacing floor coverings which led to repair of the floor, insulation installed, interior led light conversion and so it goes on. This is my first venture into restoring not looking for concourse but something that is reliable .

King Regards
Chris

Persistence is key with these things. You're experiencing the snowball effect of wanting to do a "small task" and ending up with much bigger involvement. An MGB can be a stout, reliable and fun car if you approach it with the right attitude. It seems you're doing just that. Patience and a doctor's "do no harm" philosophy are what's needed.

Good luck with the B and keep us posted. And photos are always of interest around here.

 

[drooartz]

I know that feeling -- I once decided to pull the radiator on a Bugeye to get it recored, and while I was in there... full mechanical rebuild of engine, suspension, brakes, transmission.

Good luck with your project, and do keep us informed!

 

[YakkoWarner]

I might not be understanding everything clearly - but removing the instruments from the dash shouldn't involve pulling the sensors off the engine. Unless I am missing something really important which is always a possibility...

 

[BobHaskell]

The temperature gauge/sensor isn't electric. The sensor is a bulb filled with ether that's connected to the gauge via a capillary tube. To completely remove the gauge, you have to remove it all.

 

[Aussie Chris]

Thanks to all that have responded to my questions it has been of great help. I will keep you informed of progress.
Yet another question has anybody ever used Duplicolor wrinkle paint going use it on the dash. first take it back to bare
metal using brass wire wheel , then etch prime , then 3 coats of wrinkle paint , then after about 20 min of last coat use
heat gun low temp start in one corner and move forward across the dash as the paint wrinkles. Some people don’t use
primer just the 3 coats others use primer first .
Hoping somebody may have experience at this and can tell me the best way to do it
Regards
Aussie Chris

 

[YakkoWarner]

The temperature gauge/sensor isn't electric. The sensor is a bulb filled with ether that's connected to the gauge via a capillary tube. To completely remove the gauge, you have to remove it all.

And that clarifies things - on mine the instruments are all electrical and I had never encountered that style of temp. guage before. Learn new stuff everyday....

 

[DrEntropy]

Thanks to all that have responded to my questions it has been of great help. I will keep you informed of progress.
Yet another question has anybody ever used Duplicolor wrinkle paint going use it on the dash. first take it back to bare
metal using brass wire wheel , then etch prime , then 3 coats of wrinkle paint , then after about 20 min of last coat use
heat gun low temp start in one corner and move forward across the dash as the paint wrinkles. Some people don’t use
primer just the 3 coats others use primer first .
Hoping somebody may have experience at this and can tell me the best way to do it
Regards
Aussie Chris

I've had good results with Plasti-kote wrinkle paint. Shouldn't be much difference in the two, the process is what's important. Down to bare metal, primer (etching primer preferred), then spray the piece per instructions. We live in Florida, so I just set the pieces in direct sunlight. Did restoration work for years.

Our personal '64 MGB dash done in '06 and the lower instrument panel a couple years ago. Very acceptable results, as in: factory finish. Hard to see in the photo though. Did the valve cover as well.

 

[Aussie Chris]

I've had good results with Plasti-kote wrinkle paint. Shouldn't be much difference in the two, the process is what's important. Down to bare metal, primer (etching primer preferred), then spray the piece per instructions. We live in Florida, so I just set the pieces in direct sunlight. Did restoration work for years.

Our personal '64 MGB dash done in '06 and the lower instrument panel a couple years ago. Very acceptable results, as in: factory finish. Hard to see in the photo though. Did the valve cover as well.

View attachment 77854

Yes to both questions. You can easily see the sensor protruding into the chamber underneath the thermostat once it is removed. At least half of the coolant should be drained to easily see and push on the sensor. Use a flat piece of wood between any metal prying tool and sensor so you do not damage that bulb.

Back home and followed your instructions and success after removing gauge and sensor from car tested it in the old kettle and thermometer and it still works fine. Below are the sensor out and the dash out ready for stripping and painting but it is a cold and miserable day as per the photo about 14 deg C so will tackle next week as my grandkids have come to stay and I have to play monopoly bid card game .
Thanks for your help
Regards
Chris
ps isn’t great when something goes to plan

 

[DrEntropy]

Good to see you got the temp gauge out undamaged. I've seen some where the tube had been cut, with the mistaken impression that tube was a wire. A repair is possible BUT(!) too fiddly and dangerous for most folks.

I'm guessing that's Port Phillip Bay in the last photo. You guys are heading into your winter, the heat gun would be the only way to get the paint to a temp where it will wrinkle well... unless you have an oven large enough to fit it into (and a spouse who wouldn't mind the kitchen smelling like an auto-body shop for weeks!).

Heating the whole panel uniformly would give more consistent curing of the paint than end-to-end heating it. The last coat will be giving off the carrier, evaporating at the end you finish up with and wrinkle differently than the end you start at. Do some testing on something other than the dash first. You could save yourself a lot of time and work having to strip it down to do it over.

 

[Mickey Richaud]

Yup - heat gun. Or when I did mine (used VHT brand wrinkle paint), I hung it in front of our fireplace quite close to the fire. Came out perfectly.

 

[Aussie Chris]

Good to see you got the temp gauge out undamaged. I've seen some where the tube had been cut, with the mistaken impression that tube was a wire. A repair is possible BUT(!) too fiddly and dangerous for most folks.

I'm guessing that's Port Phillip Bay in the last photo. You guys are heading into your winter, the heat gun would be the only way to get the paint to a temp where it will wrinkle well... unless you have an oven large enough to fit it into (and a spouse who wouldn't mind the kitchen smelling like an auto-body shop for weeks!).

Heating the whole panel uniformly would give more consistent curing of the paint than end-to-end heating it. The last coat will be giving off the carrier, evaporating at the end you finish up with and wrinkle differently than the end you start at. Do some testing on something other than the dash first. You could save yourself a lot of time and work having to strip it down to do it over.

I started on the dash to day we had good weather 20 deg C so I stripped the dash front and back treated the surface rust
then etched prime then a finish coat of black on the back of dash also did the dash pad and dash with duplicolour vinyl paint

have used this on centre consul and side wall panels it comes up really well see photo attached as well I replaced the centre rod of the windscreen as it was rusted see photo as well worked on my 1960 Seagull outboard so busy day.
I enjoy your comments and help with the B but if taking up to mI have time please let me know
Regards
Chris

 

[DrEntropy]

You have a Seagull!?!!! Outstanding! Only ever seen one "in the flesh" in years.

Your work on the dash is looking good. I made a new crash pad for ours, used a swimming pool "noodle" for the foam, contoured with an electric carving knife and covered with the vinyl supplied from Moss.