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        General >> Problems >> Temperature Guage not working
        
(Message started by: Savvy on May 5^th, 2008, 10:30am)

Title: Temperature Guage not working
Post by Savvy on May 5^th, 2008, 10:30am

Started last weekend, turn the ignition and the temp guage immediately goes straight up into the red. Start the car and it stays there.

Sometimes the guage bounces about a bit when the car is started then goes to the red.

It's a 2.3 with 60k. Likely to be the temp sender?

Title: Re: Temperature Guage not working
Post by Kjetil S on May 5^th, 2008, 2:16pm

Maybe. Iirc, the sender has a resistance inversely proportional to the temperature, so a short circuit to ground should read as overheating. My memory may be wrong though.

My point being, if my memory serves me right, it could also be the wire to the sender short circuiting. Check the wire for cracks.

Title: Re: Temperature Guage not working
Post by Octavian_P on May 5^th, 2008, 4:50pm

The resistance grows when colder and decreases when hot, so a high resistance (broken wire) will read dead cold. Short circuit will register boiling engine.

I also had this problem and was intermittent, i believed that the wiring was shot but in the final the sensor was the one with the problem.

Title: Re: Temperature Guage not working
Post by Savvy on May 5^th, 2008, 7:58pm

Cheers guys! Where on the 2.3 would I find the sender?

Title: Re: Temperature Guage not working
Post by Octavian_P on May 5^th, 2008, 9:24pm

I don't have a picture but i think i can explain.

As you look at the engine the ECT and the dashboard temperature sender (two distinct sensors) are bolted to the intake manifold just behind the thermostat housing. To get a better direction look HERE (http://www.fordscorpio.co.uk/manual/cooling/ThermoDOHC.pdf)

As for recognizing the sender, look HERE (http://www.fordscorpio.co.uk/ectdata.htm) here to the see the ECT. Also to investigate further just take an multimeter, set it to resistance (ohm) and measure the terminals of the both sensors. The ECT should have around 20-60 Kohm and the sender should have about 1.5 kohm

Title: Re: Temperature Guage not working
Post by jonnycab on May 5^th, 2008, 11:18pm

2.3 temp guage sender is pointed to in this picture.....

http://i70.photobucket.com/albums/i101/jonnycab/P4220033a.jpg

Hope this helps :)

Title: Re: Temperature Guage not working
Post by TiberiuS on May 5^th, 2008, 11:31pm

That's a pretty formiddable bit of gear you have there Jon, are you sure you have a license for it? ;D

IIRC that sender was from the same part of loom as the fuel injectors, the part of mine which had shed all its insulation.

Memory of my Scorp is geeting a bit cloudy now, all I see when I go to sleep now are scruffy Mondeos jumping over fences :-/

Title: Re: Temperature Guage not working
Post by jonnycab on May 6^th, 2008, 12:12am

It took me ages to find a paving slab with a red arrow on it ;D

Title: Re: Temperature Guage not working
Post by TiberiuS on May 6^th, 2008, 5:48pm

on 05/06/08 at 00:12:30, jonnycab wrote:

It took me ages to find a paving slab with a red arrow on it ;D

What? Aren't you a member of the Red Arrows anymore? ::)

Found a photo I took of the engine bay when it was all clean (those were the days ;D), on mine that part of loom snaked around the front of the manifold and into the plastic compartment where the injector wiring is :)

Title: Re: Temperature Guage not working
Post by Savvy on May 12^th, 2008, 10:26pm

Thanks for the picture. I may need to replace it sooner than first thought. Engine is getting quite hot now. Just come back from a car wash. Opened the bonnet and it was VERY VERY hot. I could hear water dripping onto something extremely hot (probably the manifold or CAT). First thought it was water from the car wash but even after it settled (20-30 minutes) something was still dripping and making that tshhh noise. Last time I had this was my 214 Rover and the head gasket went.
As my temp sender hasn't worked for the last 2 weeks or so, I can't tell if my engine's been getting hot. I'm not going to be using it now until I can get the temp sender fixed. At least that way I can see how hot the engine is getting.

Title: Re: Temperature Guage not working
Post by Tompion on May 12^th, 2008, 10:45pm

They do get pretty hot, assuming you've had the aircon on the dripping is likely to be from the drain tube.

If the aircon’s still dripping a long time after the engine has stopped then clean the drain valves here:
http://www.fordscorpio.co.uk/acdrain.htm

Title: Re: Temperature Guage not working
Post by Savvy on May 12^th, 2008, 11:02pm

Well I'm really hoping that's it. I had my aircon regassed about 5 weeks ago and it's been used most days since. Not been used for about 4 years before that! It does smell musty in the mornings and steams the windscreen. Would the water dripping from the drain tube drip on to something hot like the CAT or manifold?
I'll give the ac drain a go tomorrow - thank you for the tip!!

Title: Re: Temperature Guage not working
Post by Tompion on May 12^th, 2008, 11:10pm

Yes, drips onto the cat on mine but not normally for long after turning off the engine - I very rarely get mist on the screen, (never at this time of year) so quite likely your drains need a clean.

Title: Re: Temperature Guage not working
Post by Savvy on May 13^th, 2008, 12:28am

I have been reading about cracked inlet manifolds too. Could this be a possible cause of water loss and dripping onto the cat? Possibly the reason my temp sender has stopped too?

Title: Re: Temperature Guage not working
Post by Tompion on May 13^th, 2008, 12:50am

It could be the cause of water loss but not dripping onto the cat as that's the other side of the engine. If the water level is lower than the sender then it will read cold. The sensors are 2 wire as they can't earth via the plastic manifold so a crack won't matter in that respect. The most likely place for a crack is around the stat, in the general area JC arrowed.

Title: Re: Temperature Guage not working
Post by TiberiuS on May 13^th, 2008, 1:00am

Temp sensor is most likely just a dead sensor or loom problem, musty smell could be leaking heater matrix which would also explain coolant loss. Not saying there's no manifold prob but there are other reasons for the symptoms you have.

I used to get the dripping/sizzling, the pass side drain falls straight onto the exhaust manifold...they do seem to run very hot, mine would keep making sizzling noises for a while after I parked it sometimes, in hot weather the AC will pull a lot of moisture out of the air and put a big puddle under the car.

Regards, Bruce.

Title: Re: Temperature Guage not working
Post by Savvy on May 13^th, 2008, 8:10am

I checked the car this morning and it seemed ok. Oil was ok and coolant was at max level. I suspect it could be the AC drain. Still need to work out exactly which pipe it is I need to pull off (pic on the website is a bit too small). Still not too keen on driving it though until I've got a new sender fitted. Don't want to risk ruining a nice car....

Title: Re: Temperature Guage not working
Post by Tompion on May 13^th, 2008, 10:23am

What happens to the gauge if you just disconnect the sender?

If you replace it be careful how you tighten the sender or you will have a damaged manifold, it's a taper thread so don’t try & screw it all the way in. I used a few turns of PTFE tape on the threads.

Title: Re: Temperature Guage not working
Post by Savvy on May 13^th, 2008, 10:29am

I'm going to try disconnecting it tonight. I'm guessing it's a plug that fits on to the sender itself?
Should the temp gauge just not read anything at all?

Title: Re: Temperature Guage not working
Post by Tompion on May 13^th, 2008, 10:37am

on 05/13/08 at 10:29:21, Savvy wrote:

I'm going to try disconnecting it tonight. I'm guessing it's a plug that fits on to the sender itself?
Should the temp gauge just not read anything at all?

Yes just unplugs you have to press in a plastic catch on the plug. Look back to the start of this thread to what Kjetil S & Octavian_P said with regard the effect of shorting/unplugging.

Title: Re: Temperature Guage not working
Post by Savvy on May 13^th, 2008, 10:48am

on 05/05/08 at 23:18:34, jonnycab wrote:

2.3 temp guage sender is pointed to in this picture.....

http://i70.photobucket.com/albums/i101/jonnycab/P4220033a.jpg

Hope this helps :)

Can I ask what the other two connectors either side are for?

Title: Re: Temperature Guage not working
Post by Tompion on May 13^th, 2008, 2:45pm

There are 2 temp senders, one for the gauge & one for the engine management. The brass tube is where the hose to the heater matrix connects.

Title: Re: Temperature Guage not working
Post by Savvy on May 13^th, 2008, 4:19pm

I'm going to remove the sender tonight. I've ordered a new one from Ford this afternoon and want to take the old one just to make sure the new one is right.
Any tips on how to remove the sender?

Title: Re: Temperature Guage not working
Post by Snoopy on May 13^th, 2008, 8:03pm

CAREFULLY !