on the dancing tem gauge

[Robrt32]

I was talking to the parts guy this morning... I bought a new thermostat.. I'm quite sure i bought the cheapest one autozone sold when i put it in,but anyhow the parts guy at NAPA said it sounded like the temp sending unit to him.. Has anybody with bouncing temp gauge ever tried changing the sending unit?

 

[Masterd]

How bad is the bounce.

I replaced my sender and thermostat at the same time. Itll still heat up to the middle of the gauge and then drop back down a little, every time the thermostat opens.

 

[Robrt32]

Mine is weird.... Sitting at idle .. It will heat up to the R then fall back down to just below the N and never move... But accelerating it will raise up to the r and fall back down.. It will do it every time I slow down and speed back up...

 

[Robrt32]

It seems like the T-stat is steady opening and closing....None of my other trucks do this........I always assumed it found a place in the middle and kinda stayed there to keep the temp the same... not all the way open or all the way closed... Am i wrong?

 

[Masterd]

Maybe you got air in the system when you had the thermostat off for replacement. Try bleeding the system.

Any other weird issues that might somehow tie into this?

 

[Willard]

I have the same problem, I wrote it off to be a hairline crack in the head gasket next to a water jacket just big enough to cause a little cylinder pressure into the cooling system, therefore over pressurizing it.

I don't worry about it, it runs great and I don't really care. It's still a good idea to get a good t-stat in there and make certain there is no air in the system.

Also, my overflow reservoir overflows all the time, does yours?

 

[Robrt32]

Devilboy.....My over flow never over flows....lol....


Masterd..... no other problems runs like a top... no loss of water .. I change the thermostat last September , I wouldn't think it would still have air? I'm about to change it again with the one i bought today.. Its not a big deal but it aggravates me

 

[mikeinri]

Did you install the t-stat with the weep hole rightside up?

Mike

 

[Masterd]

Robrt32 - The biggest variance in mine comes when the truck is cold, when it first reaches normal temp, the gauge will usually drop back down to the N mark, and go back up and do that a few times slowly, but after a while it stays real close to dead center.

 

[Robrt32]

Did you install the t-stat with the weep hole rightside up?

Mike

I'm pretty sure i did but Ive been know to make mistakes.... I didn't think it work the other way though.. I haven't put the new in yet.. I'm going to this morning soon as it warms up outside a little..

 

[Robrt32]

I put the new T-Stat in..... same thing didn't make a difference... I did notice my fan has some deep cracks in between the blades.... I pulled on them and couldn't make the gap in crack bigger so it still stable.... I don't really see how but COULD this be causing it to heat up a little? but why would it then cool off? I'm at a loss.. I guess next will be the temp sending unit.. Anybody know exactly where its located? I haven't looked for it yet

 

[mikeinri]

I haven't replaced that yet, but I know I've seen pics of it here. You could also try autozone, they have Chilton's manuals online.

Remember, there are two temp sending units. One is for the dash gauge, the other is for the computer.

I would replace the fan at your earliest convenience. Not a show stopper yet, but cracks there are not a good thing.

Mike