My 409

63409

Well Known Member
If trying to adjust the timing doesn't work ,and a new radiator ,then I'll try a smaller water pump pulley .
 

409fanatic

Well Known Member
Supporting Member 1
I have not seen enough on your post to know but did you just over haul your motor and if so just a thought did you by any chance change your temperature sending unit.We had the same problem on ours as it would show hot in about 5 minutes idling so we put a heat sensor gun on the radiator, engine and hoses and found out it was normal 160 to 165. We changed the sending unit that matched our gauge and it solved the problem.
 

63409

Well Known Member
No I did not overhaul the engine recently, by the way I do have an extra temperature sending unit . I think Costco sells those heat senser guns. Thanks .
 

409fanatic

Well Known Member
Supporting Member 1
I had a friend that had a gun that just shot it. If that sending unit has been with that gauge for awhile I am probably wrong. If some one had a gun close by it wouldn't hurt to shoot it I guess. Shoot the top hose and bottom. But the other guys are probably a lot close than me..You will get it.
 

63409

Well Known Member
That sending unit has been with that gauge for a long time,I'll change it since I have one on hand .Thanks.
 

jwhotrod

 
Supporting Member 1
One ting I have noticed with the digital gauges in mine, when the thermostat opens @180 the temp will spike to 200 briefly and then drop right back to 183 and stay there. I don't know what the time lag is in analog electric senders but that just may be some of your "problem".

Big Jim
 

63409

Well Known Member
Just came back from my mechanic he said the temperature gauge is off by 20°, also my radiator needs to be replaced.
 

jwhotrod

 
Supporting Member 1
If the gauge is off that much, take a look at how much voltage is at the gauge post itself. Some of these gauges are very sensitive to the supply voltage. A friend had VDO gauges in his car and went thru 3 gauges and sendors before we figured out the voltage at the gauge was 14.3 and anything over 13v at the gauge would force it to read wrong.
 
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