accidentally broke the coolant temperature switch as i was putting the plenum back in place...went to autozone and got a new one. it broke off the wiring clip so i ended up having to crimp on another clip... so now after the change,.. at cold start the temperature needle quickly jumps to the hot side. doesnt stay at the middle like it should and constanly moves back and forth. please help?

 

Bad connection?

 

must be some weird SR5 thing then.

 

IF you used thread tape, when you installed the sensor it could effect the grounding.

 

Did you put the ground lead back on the intake manifold?

 

yes i put the ground back. probably right on bad connection. i'll just leave it for now till the next time i need to get back there. thanks everyone

 

yea...thats kind of an important component there bud....just check everything before you drive it..you never can tell when its going to overheat...and THAT thing is what tells ya it is..lol

 

I doubt it, especially for a coolant-related sender/switch.

 

Why doubt it? Thread sealing tape (teflon for instance) is not electrically conductive and since the coolant temp sender is single wire and grounds through the manifold, tape could insulate the sender resulting in erratic readings.

 

because coolant conducts electricity.

 

Yes, it can, but with much higher resistance than metal. Additionally, coolant has additives designed to reduce conductivity in order to reduce electrolysis of the dissimilar metals of the head (aluminum), block (iron) and radiator (copper).

 

bah!

I've never had a problem using teflon tape on sending units, but then again I only put one layer on the threads. ISTR the FSM saying to use it, also.

Testing whether your teflon tape is inhibiting electrons is easy, just measure the resistance between the shell of the sender/switch and the block.

But here's my original point...

If you use enough teflon tape to completely isolate the sending unit from the block, you're doing it wrong.

When was the last time you backed something out that had teflon tape and the tape was still 100% intact?