Different Coolant Temp Rdgs..Whats Going On?
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1KWIKSIX
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It's normal.
I've got the same 12deg temperature differential between my VDO engine coolant temperature gauge and my ScanMaster too.
I spoke with VDO about it and unfortunately they don't offer any another temperature sensors with a different ohm rating.....said I could add some resistance using a resistor in line to adjust it. I'll just have to live with it for the time being.
Maybe you could try to contact AutoMeter & see if they have a selection of temperature senders that have a higher Ohm ratings?
The gauge is a mechanical gauge not an electrical, It should be right on.
Any other way to really test what's the real temp? Im starting to dislike these carbon fiber gauges i also installed a boost gauge and it was giving me different readings as well from my previous boost gauge?
Could it be the scanmaster rdg is 12 deg off?
Any other way to really test what's the real temp? Im starting to dislike these carbon fiber gauges i also installed a boost gauge and it was giving me different readings as well from my previous boost gauge?
Could it be the scanmaster rdg is 12 deg off?
forcefed3.8's
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My VDO does the same thing. Now as far as the boost gauge, I have had bad luck with autometer. I had one in my GTP that started at 2psi.
Interesting, .. So which coolant temp rdg do your trust? Scanmaster or gauge? I have always gone by the scanmaster, so i setup my cooling system based on those readings like to keep my temp around 165-168 which is what it reads on SM and now im reading 180 on the gauge and im scratching my head like WTF?
forcefed3.8's
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Well now, my XFI reads around 10 to 12 deg cooler than the gauge, so it might be the factory sensor at fault. I just figured it was the electric gauge, but if you have a mechanical gauge, then I would trust that. My car runs between 170 and 185 depending on what I want to believe, I am not worried about what one is right.
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The Scanmaster is displaying the coolant temp value from the ECM which gets its info from an OEM type sensor, usually very accurate.
The gauges currently are using parts and sensors made off-shore, but even USA made components have been known to give readings that can vary up to 30 degrees?
Also, depending where the temp sensor is placed can also affect reading.
It is a good idea if using an electrical gauge that it be grounded to the engine, NOT the dash.
A mechanical pick up can be shrouded or away from the mainstream flow of coolant, or the fragile copper line can be kinked or bent sharply which may affect gauge readings?
I test all temp gauge installations with a heat gun to verify their accuracy.
The gauges currently are using parts and sensors made off-shore, but even USA made components have been known to give readings that can vary up to 30 degrees?
Also, depending where the temp sensor is placed can also affect reading.
It is a good idea if using an electrical gauge that it be grounded to the engine, NOT the dash.
A mechanical pick up can be shrouded or away from the mainstream flow of coolant, or the fragile copper line can be kinked or bent sharply which may affect gauge readings?
I test all temp gauge installations with a heat gun to verify their accuracy.
The Scanmaster is displaying the coolant temp value from the ECM which gets its info from an OEM type sensor, usually very accurate.
The gauges currently are using parts and sensors made off-shore, but even USA made components have been known to give readings that can vary up to 30 degrees?
Also, depending where the temp sensor is placed can also affect reading.
It is a good idea if using an electrical gauge that it be grounded to the engine, NOT the dash.
A mechanical pick up can be shrouded or away from the mainstream flow of coolant, or the fragile copper line can be kinked or bent sharply which may affect gauge readings?
I test all temp gauge installations with a heat gun to verify their accuracy.
Thanks Nick i have gone by the SM always now i decided to make the inside of my T-type look like an Aircraft which i regret now. All these dam Gauges, Im going to buy one of those temp guns and read directly where the gauge prong is located on intake, and see if it could be the gauge or a faulty OEM type sensor..I was leaning towards the Autometer gauge rdg incorrectly since i had bad luck with an auto meter boost gauge... you would think they make top products with there TOP prices!
RmvBfrFlght
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Check the connector and terminals at/on/for the CTS. If they get dirty or slight corrosion on them it causes the coolant temperature to read lower then true. The CTS is a thermistor that varies in resistance as the coolant temperature changes. A higher resistance is a colder reading.
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novaderrik
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The Scanmaster is displaying the coolant temp value from the ECM which gets its info from an OEM type sensor, usually very accurate.
The gauges currently are using parts and sensors made off-shore, but even USA made components have been known to give readings that can vary up to 30 degrees?
Also, depending where the temp sensor is placed can also affect reading.
It is a good idea if using an electrical gauge that it be grounded to the engine, NOT the dash.
A mechanical pick up can be shrouded or away from the mainstream flow of coolant, or the fragile copper line can be kinked or bent sharply which may affect gauge readings?
I test all temp gauge installations with a heat gun to verify their accuracy.
don't all electrical temp gauges get their reading by displaying the resistance in the ground wire thru the sender to the engine? they are just an ohm meter with temperature numbers instead of resistance values.. i've fixed a few bad electrical temp gauge readings by removing the sender, cleaning off all the teflon pipe sealant that the installer thought they needed, and putting the sender back in "dry".
My sunpro mechanical water temp. gauge reads 11 to 12 degrees lower than the scanmaster temp. reading. Strange that everyone else seems to have the opposite readings between the scanmaster and their gauges.
The difference between the scanmaster and gauge readings don't concern me as long as i can monitor the engine temp. so that it doesn't overheat,that is the main thing to me.
The difference between the scanmaster and gauge readings don't concern me as long as i can monitor the engine temp. so that it doesn't overheat,that is the main thing to me.
I just redid my fans, i use a thermo switch to run dual vette fans, i do not run a thermostat and i run straight water with a lucas/watter wetter additive i just set it up at 162 on the gauge and seems around 148 + or - on the scanmaster seems real cold on the SM...w,e might loose some mpg but i like my car running cool 
novaderrik
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I just redid my fans, i use a thermo switch to run dual vette fans, i do not run a thermostat and i run straight water with a lucas/watter wetter additive i just set it up at 162 on the gauge and seems around 148 + or - on the scanmaster seems real cold on the SM...w,e might loose some mpg but i like my car running cool
you're probably also not getting your oil hot enough to boil the bad stuff out of it...
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