I've got SW gauges in the my '34 roadster, 2 5/8" mechanical temp gauge. When decelerating, from any steady speed, it'll shoot up from 190 (where it runs, at all ambient temps), to 240, so quickly it looks like a tach needle. Instantly. On accelerating again it drops just as quickly back to the 190 baseline. The sender is in the intake just next to the thermostat, the (new) Walker radiator is full to the base of the fill neck, I have a coolant recovery tank that never has any coolant in it, it never pushes any out, and I never heard it boil. When the gauges is reading high, I can hold onto the upper hose, the heads likewise. I thought it might be low coolant, thinking maybe there was a "bubble" and the block (283) might not be filled, but that doesn't seem to be the case after 1,000 miles of driving. I can't think the coolant temp would change that quickly, just a couple of seconds, from 190 to 240 and then back. What do you guys think?
LOL, voltage? There'd better NOT be any voltage to it! It's a mechanical gauge, with a bourdon tube sender.
My bad, thinking electric with engine speed change. Only other thing I could imagine is something loose inside the gauge mechanism. Sent from my LG-TP450 using The H.A.M.B. mobile app
Loose wire are bad crimp maybe. Loose ground maybe at the gauge. Small 1/8 hole in the t/stat flange will help it burp. Oops I missed the mech gauge thing.
There's really only 2 parts of a mechanical temp gauge.... the bulb with the ether in it, and the gauge itself with the bourdon tube inside. I can't think of a way that any movement of the the vehicle would affect the expansion or contraction of the ether in the bulb so all that's left is the gauge itself. Hope it's a fairly common gauge and easily replaced.
Yeah, I'm thinking it's the gauge too. I just got the damned thing this past winter, 'cause the two old SW's that came with the car both had the tubes cut off. The SW's I have in my Diamond T truck, the Wings series, are one notch above junk, I came out to the truck last spring to find two of the pointers laying on the bottom of the gauge, they'd fallen off the shafts. The vacuum gauge, also a 2 5/8 SW, stopped working a couple weeks ago, it was fine at first, then read about 5 in. of vacuum at idle, now it lays on the peg. Must have a hole in the diaphragm. It's always something. Now today, my speedometer quit, the shaft isn't turning, so must be the speedo gear is stripped? At least the gas gauge is still working...
I’d change it over to an electrical since you have to replace one anyway. Oops.....maybe not. Those have the weird shaped gages don’t they??
I haven't looked to see if SW has an electrical gauge in that size yet. Or I can just have a dash full of non-functioning but cool looking gauges. I felt so good at first that everything worked...
Just purchased the 2" version of yours. Not cheap, but accurate. Boiled water on the stove, suspended the bulb along with two known thermometers. No effing way it can react that fast. Mechanically that is. Somewhere is a live wire grounding to the case, which would have to be isolated? Weird stuff happens to me.
LOL, you'd think for $65 there'd be some wires sprouting out of it somewhere! View attachment 3948623
Haven't had a lot of luck with mechanical gauges lasting more than a couple years. Maybe some are better quality. Sent from my LG-TP450 using The H.A.M.B. mobile app
I have a similar problem, but with cheapo Sunpro guage,...have had good luck with them for years, ...the one in my F-1 started reading around 200-210* lately after the truck is warmed up good. Checked the radiator and several spots on the engine with an infared thermometer and it reads rite at 170-190 at the most, so I figured it's just the gauge. still bugs me...I mite try shakin it as Jim suggests, ?...what would that do?
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