Roaming Temp Guage/Needle...Please help before it goes to SHOP!!!

[Bowhunt24]

Okay, So I just replaced my thermostat, and filled all my coolant up. However, my temp guage in the cab won't stay still. Once it warms up it stays right in the middle (where it should be) for a little bit, then starts to wander around. Sometimes it goes down to almost cold hangs out, then goes back to normal. Sometimes it slowly creeps up to High/Hot hangs for a second, then falls back down to normal. It is really bugging me, and I think it could be a serious issue.

Here is my theory....my car smells like antifreeze when I get out, and the coolant was really low when I just had my oil changed. Could a leak in the system somewhere cause the needle to jump around like that? If a leak isn't the cause, any other ideas what might be? Any help would be great, as I like to have a little info on my side before going to the Shop.

Happy Holidays!!!!

 

[toypaseo]

Did you burp your system?

 

[Bowhunt24]

nope, how might one burp the system? Sounds easy enough, like bleeding brake lines I'm guessing??

 

[joe doe]

if your smelling anti freeze ,did you change your radiator cap???i would top it off ...drive around awhile n see if your losing anti freeze.if so then change out the cap.replacing the stat should have cleared up the floating gauge so i suspect the cap.....unless you got the wrong thermostat???make sure you use what the factory reccomends...anything hotter or colder will mess with the computer.theres only a few things this could be apart from a bad gauge..
1-thermostat
2-cap
3-temp sending unit.

 

[Bowhunt24]

if your smelling anti freeze ,did you change your radiator cap???i would top it off ...drive around awhile n see if your losing anti freeze.if so then change out the cap.replacing the stat should have cleared up the floating gauge so i suspect the cap.....unless you got the wrong thermostat???make sure you use what the factory reccomends...anything hotter or colder will mess with the computer.theres only a few things this could be apart from a bad gauge..
1-thermostat
2-cap
3-temp sending unit.

it was the factory stat...running at 190 deg.

good info on the cap and temp sending unit. I'll try those things before i take her in and get reamed in the you know what by the shop.

Happy Holidays!!

 

[joe doe]

if this helps any,my explorer now has 91,000 miles on it and i had to replace my cap about 2,000 miles ago.was losing antifreeze.and i know it never lost any befor.you could use a ohms meter on the temp sending unit....probe the wires while its running..you should get a steady reading on cold and the hot temp...if its all over the place then theres your problem.not sure on the values..maybe someone else can jump in with that.heres something to try...top off the radiator,make sure its just below the neck,drain your rad overflow basin(follow the hose from the rad to the basin(make sure its empty)now go for a good ride n get it nice n hot .......open hood look at the basin...if it filled up with some fluid its a sure bet you need a cap.

 

[shamaal]

Resistance chart for sending units. There are two sending units. One is for computer, one is for gauge.