deuce temp

[littlebob]

After 2-1/2 years in the backyard/garage I finally got all of the brake componets replaced that needed it. Still in backyard I had a high temp on the gauge had the radiator rodded out after putting it back in and finding a lot of crud in it. It still showed hot after running about 10-20 min and I changed the T-stat. Finally got it out front to drive around the neighborhood and entertain the neighbors same thing goes to 240. It's not acting like it's hot as the radiator does not boil over.
I think I need a new gauge or sending unit maybe but wonder if a not so good ground to the instriment cluster would cause this? When I first turn on the master, the temp gauge goes to max then moves back to the middle of the arc with a cold or warm engine( not run in 4 hours)

 

[gimpyrobb]

Yup, something in the system is bad. When mine pegged to max with the on switch, a sensor in the water jacket fixed it.

 

[littlebob]

I haven't checked the TM's yet, but is there a way to check the sender with an ohmeter?

 

[gimpyrobb]

Dunno, I just swapped mine out and it worked.

 

[Barrman]

RJ,
The -20 shows you how to check the sender and the gauge for faults using a DVOM. If you don't have a volt/ohm meter, it might be cheaper to buy the cheapest mechanical gauge you can find on the bargain table and install that to make sure the truck isn't running hot.
However, Harbor Freight has meters for like $5.00. It should last you through this diagnosis before it dies.

 

[Beerslayer]

My sender was bad and I ended up installing a Stewart Warner mechanical gauge from Napa, it was about $45. Only downside is that there is no gauge illumination.

 

[Jake0147]

The gauge receives power from the "spider wire" behind the instrument panel. The sensor IS the ground for the gauge. It's a variable ground.
The advice above is good. The manual and an inexpensive volt meter. (Don't drop them, and even a crappy one is pretty accurate and lasts for quite some time).
Guessing at parts (I don't know, so I've heard) is about the most expensive way there is to diagnose electrical issues.

 

[DuecesWild]

I also have sorta the same problem. After I first start the truck and drive for a couple min the gauge will just peg 240. The truck can be off with the power switch on and I can tap the gauge and it will peg. Its got a brand new temp sending unit and it still does it. Im gonna pull the gauge out sometime I just havn't gotten around to it. Sorry littlebob for hijacking your thread.

 

[gimpyrobb]

DW, check the wire for a short to ground.

 

[littlebob]

RJ,
The -20 shows you how to check the sender and the gauge for faults using a DVOM. If you don't have a volt/ohm meter, it might be cheaper to buy the cheapest mechanical gauge you can find on the bargain table and install that to make sure the truck isn't running hot.
However, Harbor Freight has meters for like $5.00. It should last you through this diagnosis before it dies.

Thanks Barman and everyone else that replied! I always keep two of the $5
meters on hand, can't stand not being able to finish at 7:05 when HF closes at 7:00 a couple blocks from the house! I'll try and find in the TM.