The Stovebolt Site Forums The Shop Area The Electrical Bay Early 235 Electric temp senders

I'm trying to get the stock electric temp gauge in my '49 GMC working. GMC engine was replaced with a '54 Chevy 235. In another post RED58 advised me that Chevy switched from capillary tubes to electric by '55 1st or 2nd. Went to NAPA today and they couldn't help with an electric sending unit... they had no info/stock #s/etc before '63. Can anyone give me a suggestion, lead, or source for an electric temp sending unit for my '54 235 that might work with the '49 GMC AD/ND stock electric temp gauge? I would imagine the early 235 electric temp senders would match fine with my gauge. Thanks in advance.

Sounds too old for electric guage. any sender can be made to work if the guage is 12 volt.

Mike;
Have had the same problem with my '49 GMC. Has a 261 Chevy engine in it and electric temp gauge. My sender is in the side of the thermostat housing and has never read out on the gauge correctly. The sensor is an NTC type or negative temperature coefficient. As the temperature rises, the resistance falls and vice versa. I got a model TS-6 sensor which was made, I believe by Standard Parts but it would read 135 when the real temp was 180. Tried installing a variety of resistors inline with the sensor wire but they either pegged the gauge or it wouldn't read at all. I have another sensor (original) which came off the 261 head I had but the engine is currently out of the truck for a rebuild so I don't know if it will read correctly or not. Can't help anymore than this until the engine goes back in and I get it started. I'll repost if I come up with anything.

I've got a 261 in my '51. I used the original temp guage (mechanical/capilary tube type) with an brass bushing adaptor to fit the sensor in the head because the '51 sensor is smaller than the one used in my 261 and other post '54 235s. The gauge works just fine.

Maybe you could get replacment guage for $50 +/- (which will come with the sending unit), a bushing, and move the plug currently in you head on the driver's side near the back to the thermostat housing, where you elcectric sensor is right now.

The Chevy Duty catelog has a picture of the bushing for about $6.00, Part # 24-811. The guage itself is about $50 from Chevy Duty,

Jim Carter has the gauge for $50
http://www.oldchevytrucks.biz/catalog1/0161.html


Our Host, American Classics, has it for for $90
http://www.americanclassic.com/asp/...&iyear=1949&ytype=to&exyear=

Jim Carter has an electric sender for the later 235/261 (55-62) in their 55-66 catalog. However, The '54 235 head has the small hole (for the mechanical sender), so you might be out of luck, unless you have a later head.

Thanks to all for taking the time to offer suggestions and get me pointed in the right direction.

Chester - Working this problem I've come to learn that several GM products (Caddy, Olds & Pontiac)had electric temp gauges & sending units in the 30's & 40's.

NM51 - If I ever decide to convert from electric to capillary tube your suggestions will be helpful. Thanks.

49 Geezer - It's always great to hear from someone who has already worked the same problem. Many thanks for your imput. I'm thinking that even if I don't get an accurate temp readout on the gauge head I'll be able to identify a "normal" heat range and know I have a cooling problem (broken fan belt, etc) if the needle gets out of that "normal" range. I'll look forward to your repost when you get the 261 bedded down.

Tim - Thanks a million... just the lead on an electric temp sender I needed. Guess I lucked-out this time since the capillary tube sender in my thermostat housing has a bushing to make it fit in the larger hole. When the capillary tube sender and bushing come out the electric sender should go right in. Got a sender on order thanks to you.