My water pump was leaking quite a lot so I got a new one, threw it in there, all good on that front.
In the process, I took the radiator out, and as part of that I removed the temperature sensor. It seems like the bulb and the threaded part to put the bulb in our one piece, so I unthreaded it when I took it out and threaded it back when I put it back in.
I am now finding out that the bulb is apparently not meant to twist at all, and I have broken the seal where the wire goes into the bulb. It sounds like that used to be pressurized with either. That is no longer the case.
Is there a way to refill this and seal it back up? How would one handle this issue?
Temperature gauge worked before I did everything, and no longer does.
Yes you did a bad thing! You’ve broken the seal between the capillary tube (it’s not a cable) and the bulb. There’s a flat near the base of the bulb to hold it still with a spanner while you undo the nut. The bulb is filled with di-ethelether which could be got from a chemical or medical lab supply company. The trick is to refill it. You will notice a solder blob at the end of the bulb. If you unsolder it you will find a small conical wedge stuck in a hole which must be pulled out. Di-ethelether is very volitile so it’s just bout impossible to keep the bulb cold enough to stop it evaporating while you resolder the wedge in. I’ve tried sealants and epoxies but they never last long. I’ll try JB Weld next. In the meantime I’m running with a generic mechanical guage mounted under the dash in my Mk7.
A PO cut the capillary tube about halfway between the bulb and gauge when he dismantled the car. I considered attempting a repair but opted instead to send it to West Valley Instruments. It came back looking and working like new. $185. He may charge less if it’s a simple refill and solder job.
