Autometer water temp gauge issue..electric

[DMAN302]

I have noticed that the last few times out my autometer was ticking past the usual 180-185 to near 195 or so then suddenly and I mean suddenly drop 10 degrees...to fast for Tstat opening IMO..I mean 1 second and bloop...10 degrees and sticks at normal temp. Anyone ever see anything like that? Wire is secure and sender is less than a yr old...very strange..any help or thoughts appreciated. should note that once it returns to normal range it floats nicely between 180-185 as it should.

 

[srothfuss]

My autometer electric seems very fluid in its movements. Maybe you have a bad ground?

 

[DMAN302]

mine is also very fluid..and the rise and sudden fall seems to only happen one time every time out..rest of the time the temps are perfect 185 highway and just under that at idle and inner city...

 

[HISSIN50]

I had a Marelli gauge that used to do that. I'd email Autometer - I'd be surprised if they didnt send you a new sender gratis.

Absent a sender issue. I agree about ohming out your sender. It should be fine unless you really doped the threads up. You could add a ground strap but not on your engine bay Derek (I doubt this is the issue anyhow - if it is we'll deal with it).

Good luck and bumpity.

 

[DMAN302]

well since the last few times it did the rise and fall..I am thinking the stat may have been hanging a bit. Since the car is not driven as much as it should I'm inclined to think getting it out and driving it might very well condition the stat to work properly. The fact it maintained good temp prior to and post acting up and not quite to the high degree with each episode I might just try to drive through it.

 

[DMAN302]

so hard to diagnose somthing when it doesn't occur regularly or in the same manner...like bringin the car to the dealership for repair and leavin cause you can't get the car to do what it was doing before.

 

[795.0pacecar]

Mine was doing something similar, it would jump up to 230 degrees from 185. Turned out the threaded post on top of the sender where your wire hooks into, was loose and grounding out. If I remember right, I was able to tighten it up. Havn't had the problem since.

 

[HISSIN50]

Derek, maybe after it sits for a few days, you can let it idle and watch the gauge. When it hits 180, start feeling the hose (or have your cap off so you can see flow. Be careful of burping coolant and all that) and note when the stat seems to open vs what the gauge reads. If you have the cap off, you can use a turkey thermo to compare to the guage temps (it'll be off a hair, but somewhat close).

Random weird ideas.

 

[DMAN302]

well the damn thing wont go over 180 if I let it sit..curse you and your 'I recomend a new HD clutch fan' thing does wonders at idle....again making diagnose difficult. I would have to pull of the road the while it's coming up but it doesn't last long enough for me to even attemp to find a way to determine if I'm actually up 10 or 15 degrees...car hates me some times I never get the easy ones. this only occurs while driving to date...and only on initial time car warms up while driving. The fact it only occurs first time while warming up on the road and not again is what leads me to blame the stat (more I think about it the more it makes sense..) However since the issue won't come up again after it's occured the first time unless it gets worse I will probably see if it won't work it's self out. Damn I think I may be able to figure this one out without spending money...first time for everything

 

[HISSIN50]

Gotcha. Sounds good to me. If you feel the need to spend money, I could use some springs.

So it doesnt stick at idle? I figure you have a nice quality stat (if you recall it being balanced, it would be). An unbalanced stat allows for the crashing coolant to smack the pellet, which is one cause for a stat opening late (it can get really horrible for guys that autocross; this phenomenon at 6K RPM can make an unbalanced stat open 15+*F late).

I wonder if this is what happens initially (while driving, where coolant flow is more turbulant than while idling, where it doesnt occur). Then after it opens once, the pellet is loosened up and works fluidly? Or it's just a tempermental stat. I think you're right and it might just really be a sticky stat.

It sounds like you have a firm grip on it and it really aint no biggie. You op temps are great.

I'm glad to have been of no assistance.