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maybe a dumb question

delbertinie

New member
I'm wondering if I have a bad sending unit.
At times when I turn the key my oil temp gauge reads 0 at other times it reads 150 dergrees
cold!

It seems that when it gets up to temp its about 200 to 240.
I have an oil pan sender.
Also, from the gauge back I a very small diameter wire and the last 2 feet is thicker wire wonder if the problem is there. anybody got any ideas
 

letterman7

Honorary Admin
No, no dumb questions, only those that go unasked. If the gauge is Stewart Warner, then the possibility of the heavier wire screwing the readings may be the culprit since it changes the electrical resistance. The fact that it's reading somewhat correctly when warmed up tells me it may be a simple case of a bad ground at the sender itself - as the engine heats up it creates a tighter bond. Check your gauge ground as well. If that doesn't fix the issue, then yep, the sender is probably toast. Easy enough to find a new one, though!
 

delbertinie

New member
No, no dumb questions, only those that go unasked. If the gauge is Stewart Warner, then the possibility of the heavier wire screwing the readings may be the culprit since it changes the electrical resistance. The fact that it's reading somewhat correctly when warmed up tells me it may be a simple case of a bad ground at the sender itself - as the engine heats up it creates a tighter bond. Check your gauge ground as well. If that doesn't fix the issue, then yep, the sender is probably toast. Easy enough to find a new one, though!

yep its a stewart warner old stage three same vintage as the car. new sender though
 

letterman7

Honorary Admin
But is it the correct sender? SW had multiple temp senders - you need to find the one that is the right ohm reading for your gauge. The back of the gauge may be marked with a serial number; you'll need that. Worst case scenario, scope eBay for the same style gauge and sender.
 

delbertinie

New member
But is it the correct sender? SW had multiple temp senders - you need to find the one that is the right ohm reading for your gauge. The back of the gauge may be marked with a serial number; you'll need that. Worst case scenario, scope eBay for the same style gauge and sender.

yeah bought this one flea bay no ohms description.

discription was 0 to 300 degrees stewart warner.
 

delbertinie

New member
must be a short in the wiring went for a few minute drive ( illegally)*nothing to see*and it bounced all over the place*insane**hmmm* even pegged at 300 and stayed for a minute
 
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