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New To Old Gmc Truck And Need Advice

jobad72

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jobad72 New Member

jobad72

Posted
Posted

I just got a 1978 Sierra Grande 3/4ton pickup for $500. Think I got a pretty good deal cause its only got 1 rust spot on it. I bought it for my daughters 1st vehicle. She wanted it, to my surprise. Anyway, i have a couple questions. 1- The fuel guage always shows way past full and never changes. It does have dual tanks at I think 44 gallons. 2- The temp guage, even on hot days like yesterday, 105 here, never gets even 1/2 way to H. Is this normal or should I get a new thermostat?

 

Oh and its only got 84k miles on it. Ive known the guy I bought it from for years and he is the original owner so im pretty sure it is 184k. Thanks for any help.

Doug_Scott Senior Enthusiast

Doug_Scott

Posted
Posted

Fuel gauge could be sending unit, or bad ground on the sending unit. How long does the temp gauge take to get to half way? Quick way to test for stuck or missing thermostat is take the rad cap and start the truck when cold. Does water flow right away in the rad when you look in? If it does, the thermostat is stuck open, or just not there. BTW, running without a thermostat will still overheat, just take longer. The water needs to be in the rad for certain length of time to give up its heat. Water flowing too fast just does not have enough time to cool. If you really like the idea of no thermostat, go to your local speed shop (for cars, not for buzz) and get a Moroso water restriction kit and try the 5/8 size first.

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