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temp gage on a l small block gary beaupr does anyone know what temparature readings the lines on an l small block temp gage correspond to my gage has the number around the position corresponding to a line at around o'clock another line at around o'clock a line at the o'clock position with the temp reading and the a line and orange red bands and the number further clockwise from there does anyone know what temperatures the unmarked lines correspond to particularly the one at o'clock position the needle on my gage never reads as high as the o'clock line and i'm wondering if i have a bad temperature sender the resistance between the sender contact and ground reads about ohms when the car is cold and the ambient garage temperature is around degrees finally if i have to replace the temp sender should i use a gasket sealer on the threads or will this look non original thanks gary
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Which thermostat are you running?
which thermostat are you running jerry bramlett gary from the resistance reading it sounds like your temperature sending unit is okay have you looked to see which thermostat is in your engine perhaps the original degree thermostat has been removed and replaced with a degree unit i think the o'clock hash mark on the dash gauge corresponds to about degrees -
Re: Temp gage on a 1966 L79 small block
re temp gage on a l small block nick liarakos i have wondered the same about the temp gauge on my ls based on your description my gauge seems about the same there is a degree mark at the position another mark at degrees at and at mine rarely runs over that mark between and i was assuming this is about degrees my thermostat is a does this sound normalComment
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Re: Temp gage on a 1966 L79 small block
re temp gage on a l small block gary beaupr nick sounds to me like your sender and gage are giving reasonable results with a thermostat i'd expect the needle to sit between the o'clock position and the o'clock marking at least i'd be happy if mine did that however i'm not so sure that the o'clock position corresponds to several people i've talked to have guessed the same thing i assume based upon a linear interpolation between and however the markings may not correspond to a linear division for the high temperature markings i don't think a linear subdivision holds noland adams says that the orange band corresponds to and the red band to if is correct for the lower orange limit then the line at the o'clock position is more like degrees or degrees more than the o'clock reading if the delta is the same between the and the o'clock reading this would imply that the o'clock temp is more like or but all of this is pure guesswork on my part which is why i'd like to hear from some people who have seen something in the official gm documentation somewhere garyComment
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Re: Temp gage on a 1966 L79 small block
re temp gage on a l small block jack humphrey much of this confusion stems from current replacement temp senders you can get them from chevy united delco and non gm sources napa if you read the fine print in the reputable catalog house listings you'll find a disclaimer that says paraphrase these are ac delco parts and may vary up to degrees from actual factory original parts will have an ac delco emboss on the non threaded portion of the shaft beneath the hex head also you'll see what we believe were ac factory binning sorting marks preceeding the ac delco emboss both and markings have been observed and no dotter one dotter and two dotter marks have been observed it's believed these marks dealt with final test sort of individual temp senders i've seen room temp nominal resistance readings vary from the high to low ohm range based on dot count remember in those days not all cars had temp guages some had idiot lights to indicate overheat condition the only really good way to make your temp guage accurate is to use a high precision thermometer hvac contractors have ir point shoot guns and compare the true coolant temperature rad outlet hose is rubber and therefore a pretty good measurement point for actual coolant temp to your guage readingComment
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Is a 900 ohm reading too high?
is a ohm reading too high gary beaupr jack the resistance for my sender is ohms does this clearly sound out of whack to you based on a article in the ncrs restorer ohms is supposed to be the average correct reading for a cold car and if the resistance is much higher then the gage will read low which mine does i don't know what thermostat is in the car but the needle on the gage reads between the and lines which seems low to me the car runs great and the choke doesn't stay on so i'm thinking the actual temp is in the range even though the gage would indicate otherwise garyComment
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Re: Temp gage on a 1966 L79 small block
re temp gage on a l small block mark lovejoy gary i don't think a gasket sealer is a good idea from an electrical standpoint you need a good ground to make the circuit work properly never use teflon tape on such things either because they surely will not work afterwards best regards mark ' dComment
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Re: Temp gage on a 1966 L79 small block
re temp gage on a l small block gary thanks for the tip mark i appreaciate all the good advice i'd be lost without this web site garyComment
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Re: Temp gage on a 1966 L79 small block
re temp gage on a l small block gary schisler gary i found three temp sending units plus i pulled the one off of my car here is what i have found ac made in usa volt reading is ohms ac made in usa volt reading is ohms ac made in usa volts reading is ohms note that is says volts not volt ac made in usa volt reading is ohms note note all the periods after and before the stars are actually dots and not periods in addition they are halfway up the letter as opposed to down on the bottom of the line is off of my car and the printing is upside down whereas the other three are right side up all readings are taken in cool garage at around degrees it sounds like your unit is ok based on this and the other commentsComment
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Re: Is a 900 ohm reading too high?
re is a ohm reading too high jack humphrey temp senders were not precision devices see my prior post that's one of the reasons the temp gauge is vaugely calibrated across it's range you know you're in trouble when car overheats dies pops the pressure relief of a correctly working matched rad cap and or continues to puke coolant on you a no dotter original ac sender i pulled at random from my spare parts stache read ohm at room temp the ac service replacement sender in my ' sb that reads a tad on the low side measured ohms at room temp why not get in touch with fred oliva at vintage automotive research in coral springs florida fred keeps a handful of tested reconditioned original ac temp senders on hand for the serious restorer who wants true factory originalityComment
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Fred Oliva
fred oliva gary beaupr jack thanks again for the tip fred restored my original fan clutch and did a beautiful job i didn't know he restored temp senders as well i'll contact him garyComment
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Re: Fred Oliva
re fred oliva jack humphrey good also beware of drawing inference from room temp resistance readings off temp senders often electrical components have a linear range where they're meant to work and when you get out of this range all bets are off on drawing calibration conclusion s for temp senders room temp is a very uninteresting operating point to the system could well be test check of sensors in this area of their operating curve is a meaningless exerciseComment
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