Help! Temperature needle going up then down!

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adampuma

New member
Joined
Oct 9, 2011
Messages
1,015
Noticed the other day when driving my car my temperature gauge needle was rising up to the top of the word- NORMAL then 5 minutes later it dropped to just below the middle where it ntnally sits, then a few mins later it sat where it should do, i am a bit worried, what sensor could it be? I doubt its overheating as theres no dodgy signs, no water pump noise, no bubbling in header tank etc.
From this

To this
 
Please guys, i dont want to drive my car like this, need to know whats the best thing to do? What sensor could be at fault? Could it be my waterpump?! How can i tell?
 
If it's not gone beyond normal, then why are you worrying? If it soured off into the red and didn't come back down then that would be a problem. Just keep a careful eye on it I'd say.
 
The temp gauge to my knowledge has never been any higher than right in the middle, something has changed as its now rising up to where you can see, the temp seems to slowly rise up in traffic, then drop again whilst still in the same traffic.
Is there anything i can replace/ change? As a preventitive measure? My heater blows hot and cold as it should.
 
I would go for the thermostat, and while you've got the cooling system down you may as well change the heater control valve as well if it is the original (50k miles it could still be the original).
As The Arch Bishop says, as long as it doesn't go into the red should be OK.
But the normal temp position is centre.
My lad's '99 1.7 recently dropped to about 1/4 position under normal running. New thermostat and now it's back on halfway, never moves from there once up to temperature.
Paul
 
Well i might aswell change all of it seeing as the rest of the car is pretty much new, will go for engine temp sensor first, process of elimination. Hope its not the water pump
 
Those two pictures show you were driving faster when the gauge was up but slower when the gauge was down.....
 
Changed the coolant temp sensor this morning, no difference, been told by two people it may be the thermostat, so i eill be changing that next, does anyone have a guide or can give me a good idea how to change it and what it looks like please?
 
adampuma said:
......... does anyone have a guide ..............
That will be the "How To Guides", then. :grin:
http://www.projectpuma.com/viewforum.php?f=51" onclick="window.open(this.href);return false;
 
Going to change the thermostat in the next few days, do i need to change the housing at the same time?!
 
These have been known to fracture and leak, so unless you're on a really tight bugdet (they're not cheap) I would replace it.
Mainly because it's such a faff of a job getting to it and while you're in there.....
Paul
 
I've seen this happen, it can be the hcv. Be Careful when replacing as there has been a faulty batch of HCVs. Ford are aware of this.
 
The housing was about £15 on Euro Car Parts when I ordered last week, so not expensive. The only difference between the original and the pattern one was that the pattern one had strengthening metal collars on the bolt holes.
 
Little update on this, i changed the thermostat and housing, have also changed coolant temp sensor, waterpump is working fine and had no dodgyness when checked.
My temperature gauge now permanently sits low and i tested it by driving 30 miles to a car show and back, the gauge sat cool all the way there and back.
Pic of where it sits, when sitting stationary in traffic it still sits below where it should although it does rise to just under half way.
 
Hello, Adampuma.

I'm having the same problem. I've already changed the HCV, but the problem persists. How did you solve it?
 
If you have an analogue instrument cluster, the needle is being fed by a separate sensor that is below coil pack. You will see it, a separate wire goes to it. It has been known for that wire to go bad at connecting point, but could also the sensor. The digital instrument custers needles are being fed directly by PCM and have a flatten response; i.e. the PCM will be holding the needle in the exact center of the scale regardless of the actual temperature (the thermostat starts opening at 82C and is fully open at 88C)

Have a look here: https://www.projectpuma.com/viewtopic.php?t=10548&start=975

And here https://www.projectpuma.com/viewtopic.php?f=19&t=29307
 

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