Swinging needle on temp gauge syndrome...fixed?

[doonze]

So, I've been working on my cooling system for about 5 months now. Just about the last things I had left is to figure out were where some of my fluid is vanishing too every once in awhile... and my swinging temp needle.

So here is what I would get, when first coming up to temp each day it would rise to about O the jump quickly to A/L then slowly fall back down below N. It would do this almost every day (or every time it was allowed to cool down). It would spend the rest of the time moving from O or R under load.

Then on days it was really cool, like it is now most evening on the way home, the gauge would hover around N, jump to like r/m, then fall back to N, then jump up to r/m, fall back to N, so on and so forth all the way home...

For a long time I figured I've had bad stats... But I decided for $4.99 from Advanced Auto I would give a new temp sending unit a try.....

Seems to have fixed my issues (so far), it now hangs out around O once up to temp, might move from one side of O to the other under load, but no more movement then that. When coming up to temp, it hits O, then drop down to low N and slowly climbs back to low O. But nothing like it used to swinging all the way to L. So far seems to overall read a TAD lower then before, but no swinging like it was....

We'll see if it sticks, I'll post up if it starts up again. Been 4 days now!

 

[Anime]

In my experience, the temp gauge sees more action with cheaper 'stats that have weaker springs, or for some reason only open once the system is at operating temp and the pressure builds so it finally releases the coolant flow.

 

[mikeinri]

As I was reading the description of your problem, it was screaming "Sender Unit!!!"

The way your new sender unit is working is normal in my experience, at least on my older Explorer. Gets warm, cools down when the t-stat opens, warms back up. Once it equilibrates with the t-stat open, it shouldn't move much.

This is even more noticeable when it's really cold outside.

Mike

 

[doonze]

I thought it was the stat for, well, forever. I mean, why would a bad sending unit act the way my gauge was, I made much more sense if I had bad stats and they were opening and closing and not controling the temp lvl very well.

However, after 3 stats, and ALL of them acting the same way (however the one that ran the coolest was the cheepie $4.99 Autozone one) I started to think maybe it was the sender.

My current thinking is that when the temp changed a few degrees quickly, the sender would over compensate and cause the gauge to jump way up, then it would settle down once the temp leveled out and start reading right again.

The new sender is pretty much rock solid, not any more movement then from one side of O to the other, and it makes sense as it goes up under load, and falls once load is gone (hill climbing for example). No wild swings anymore (so far), I will keep an eye on it.

 

[mikeinri]

Yes, I know. T-stats don't get much respect. Too often, they go bad, and the new one you put in doesn't work...

Mike