Coolant temp gauge wire spews refrigerant?

Scott & Heather · June 08, 2015, 05:30:07 PM

I was rerouting the engine bay coolant temp gauge wire on our 102C3 when I must have broken it and it began spewing some nasty smelling liquid that was very cold (on a 96 degree day). I've never seen this before. Thankfully I had a brand new spare mechanical gauge and I swapped it in...but can someone explain that phenomenon to me??

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luvrbus · June 08, 2015, 05:37:12 PM

Wire ! are you sure it's not a copper tube

Geoff · June 08, 2015, 06:51:46 PM

You just lost your R22.

Scott & Heather · June 08, 2015, 08:29:11 PM

There was teeny tiny copper tubing inside a braided stainless mesh. It ran from the coolant temp gauge mounted in the engine bay, to the sensor near the tstat. I have a video but can't seem to upload it. I'll try.

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Scott & Heather · June 08, 2015, 08:32:48 PM

Here's the video:
http://www.youtube.com/watch?v=2nv_rsAIukE

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Tony LEE · June 08, 2015, 10:46:51 PM

http://www.secondchancegarage.com/public/653.cfm

QuoteA Bourdon Tube is a thin metal - usually brass or copper - tube that is filled with an easily vaporized fluid, typically alcohol. It is sealed at both ends. At the gauge end it is formed into a circle or spiral with its end attached to the indicating needle by some form of linkage. The other end is fitted to a water-tight connector that is in direct contact with the coolant in the engine.

As the coolant warms up the alcohol in the Bourdon tube expands. The expansion transfers its force to the coiled end of the tube inside the gauge. As the coil or spiral unwinds it pulls the linkage on the needle, which in turn shows a temperature reading on the gauge face. The gauges are calibrated during the manufacturing stage and are not adjustable afterward.

Since the Bourdon Tube design is purely mechanical the gauge will continue to read some temperature level even after the engine is shut off. As the engine cools the gauge's needle will return to its rest position.

Bourdon Tube gauges aren't used anymore because of cost and convenience factors. The tubes are delicate and must be carefully routed from the dash to the appropriate fitting on the engine. The gauges themselves are far more expensive than electric or electronic gauges and if the tube is kinked or split the entire gauge assembly must be replaced.

Scott & Heather · June 09, 2015, 07:28:50 AM

Thank you so much! This was vexing me. I searched the Internet far and wide without success! Cool stuff! Had no idea these existed.

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