MrEarl

Water temperature idiot light not working, questions

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Posted (edited)

I’ve got a 195 degree T-stat as that is what’s recommended by the factory. On the 403, the fan clutch engagement should be at 190

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Edited by dmfconsult (see edit history)

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1 hour ago, MrEarl said:

 

Does the 258 apply to the 403? 

 

New fan clutch with new AC install. 

 

Haven’t looked at the thermostat yet. Going by the temperature gun readings on the hose at the thermostat it appears to be a 195 thermostat. Someone had suggested a 160 but from what I read the 403 needs at least a 180 for pressure to get coolant through the Siamese heads. Myth?

 

 

If it is 195 at the T-stat it should be good.  Was the 258++ detected before the new fan clutch?   The fan clutch makes a world of difference. 

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The 258 is the factory setting for the light which should be measured close to the t-stat housing. Would be hotter at the heads.  On mine with the temp reading 195-200 with an infrared thermometer at the t-stat housing, the heads are reading 220-225 if memory serves correctly. 

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17 hours ago, MrEarl said:

 258* eh?

 

You might want to see if you can buy a sensor that would turn the light on at a lower temperature to give you an early warning to start watching a temperature gauge (you really should install one for towing).

 

Good eye on finding that bent tab on the connector. It could have been that way from the factory.

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16 hours ago, dmfconsult said:

The 258 is the factory setting for the light which should be measured close to the t-stat housing. Would be hotter at the heads.  On mine with the temp reading 195-200 with an infrared thermometer at the t-stat housing, the heads are reading 220-225 if memory serves correctly. 

 

 I have been shooting at the very base of the thermostat housing at the bolt flange. Shot it yesterday at the top of the housing and found it to be 7-8* cooler. I like that, I think I'll shoot it there from now on 😄

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@MrEarlDid the radiator core fins get flushed?  With garden hose nozzele, from the fan side to the front end ought to do it.

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Did that and with air too.  The radiator was replaced at the same time as the head job so is fairly good and clean. Looking in through the filler hole it appears to only be a single core though which is surprising as I would have thought they would have replaced it in kind, which would have been at least a double core given it was a tow package car. It IS a thick 1.25" core though with wide fins. I have seen "single core - three core equivalent" advertised though, so maybe?

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What about the timing and the heat riser valve?

 

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Right around the turn of the century my TEMP light started coming on right after starting the car, even before it warmed. I put on a temporary test gauge and tie wrapped it to the abandoned AC liquid line. I still open the hood an take a peek at it after driving.

 

I gotta get a new sending unit in there before the tie wraps go bad.

 

Oh, 41 years without an AC compressor. Maybe I will do the sending unit and the AC when Red Riviera Bob gets his air going.

 

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