Coolant temperature guage

MARTYNG · 11-07-2006, 09:59

I would appreciate any advice on the following problem on my Y reg Fabia SDI.

From starting the engine, the needle/guage appears to be working normally ie climbing from left to right and settles at the vertical position. It never used to move from that position regardless of road and traffic conditions.

However, after reaching vertical and settling at that point, it now drops back towards the left. It settles at various points between vertical and the mark midway between cold and vertical

I am not a techie but given that the coolant level is ok and I can find no other problems, I suspect that either the guague itself or a sensor providing it with the information is faulty.

Your thoughts would be appreciated as to cause, solution and likely cost.

thanks in advance
Martyn

AwesomeSarah · 11-07-2006, 10:26

Hi Mate
I would say coolant temp sensor.
They do suffer with these.
Easy cheap fix , so could be replacing that to start
Hope this helps
Sarah

MARTYNG · 11-07-2006, 10:36

Sarah - thank you for such a quicky reply.

AwesomeSarah · 11-07-2006, 10:56

No worries mate.
Easily done yourself too.
Do you know your way round the engine?
I have known someone be quoted £100.00 + VAT for this job and it is quite easy to do when you find the sensor.
It is located on the thermostat housing.
Sarah

ScoobyChris · 11-07-2006, 11:12

I always assumed this happened because a diesel engine is thermally efficient and I noticed this behaviour on my old Fabia TDI (ie in the winter you could sit stationary in a traffic jam and watch the needle drop).... Under what conditions is the needle dropping? If it's when the engine is being worked hard, I'd say there is a problem but if it's cruising/idling I wouldn't worry

Chris

MARTYNG · 11-07-2006, 11:13

Hello Sarah

Other than checking the oil, coolant, brake fluid and windscreen washer fluids, I am a complete dummy when it comes to what's under the bonnet.

Unless the sensor is a simple push on fitting without needing to unscrew/unbolt parts of the engine, I will probably have to pay a garage. I don't even know where in the engine to look for it. Unless it is marked in big letters in luminous paint I will probably never find it!

Haynes' manuals may be great for mechanics but no good for dummies like me!

thanks again for your advice
Martyn

MARTYNG · 11-07-2006, 11:16

Hello Chris

It is dropping when cruising on a motorway and in town driving. It never used to move so it seems odd that it now drops

Martyn

AwesomeSarah · 11-07-2006, 11:20

Mine when reaches temp does not move at all idleing or moving it does not move
I have the 100PD one
So I would think that it is reading incorrectly.
I am sure there is a how to guide on this.
Check out the Fabia section on here as I think it could be there
Sarah

Kerry · 11-07-2006, 13:27

Sounds more like a thermostat stuck open to me. I've had it on two, or three, different cars. Temp drops at idle and in slow moving traffic and the heater output falls off.

fordfan · 11-07-2006, 18:05

Quote:

Unless the sensor is a simple push on fitting without needing to unscrew/unbolt parts of the engine

It more or less is. With the engine cold unscrew the tank cap, squeeze and hold the top radiator hose and screw the cap back on (this creates a little vacuum in the system to prevent coolant loss). Disconnect the sensor electrical plug (pull the tag and simultaneously push the connection onto the sensor and then pull it off), remove the sensor clip, pull the sensor out, retreive the rubber seal, either re-use or replace onto the new sensor, push the sensor into its' housing and re-fit the clip and plug. Unscrew the cap to sort the pressure out and screw it back up - also check the coolant level.

AwesomeSarah · 12-07-2006, 08:32

Quote:

Originally Posted by fordfan

It more or less is. With the engine cold unscrew the tank cap, squeeze and hold the top radiator hose and screw the cap back on (this creates a little vacuum in the system to prevent coolant loss). Disconnect the sensor electrical plug (pull the tag and simultaneously push the connection onto the sensor and then pull it off), remove the sensor clip, pull the sensor out, retreive the rubber seal, either re-use or replace onto the new sensor, push the sensor into its' housing and re-fit the clip and plug. Unscrew the cap to sort the pressure out and screw it back up - also check the coolant level.

There you have it , it IS that simple.
Sarah

MARTYNG · 12-07-2006, 11:24

sounds simple enough for even a dummy like me!
Many thanks to all of you for your advice

Martyn

Hammett · 13-07-2007, 11:45

Had this problem with my Octavia (2002 Elegance TDI MK1 110BHP). Engine would warm up to normal temp then guage would just drop then go back to normal after a few mins. Got it serviced a few weeks back and the VAG-COM picked up an error on the coolant temp sensor, so they swapped it (although it doesn't look new to me, probably just twiddled with it until the code wasn't produced). Try just pulling the sensor connector off and checking the contacts. The sensor is located on the side of the coolant reservoir and just pulls of I think (there maybe a clip if I remember correctly). Haven't had any issues with it since.

ap0gee · 13-07-2007, 11:58

Quote:

Originally Posted by MARTYNG

sounds simple enough for even a dummy like me!
Many thanks to all of you for your advice

Martyn

I did a guide here. Covers most of what you need, but you'll need to make use of fordfan's advice unless you fancy draining the entire thing!

HTH

TDi Vrs · 13-07-2007, 12:09

it also sounds like a faulty thermostat to me

Bigw2069 · 13-07-2007, 12:17

Quote:

Originally Posted by ap0gee

I did a guide here. Covers most of what you need, but you'll need to make use of fordfan's advice unless you fancy draining the entire thing!

HTH

Dont scare the guy ap0gee, thats your guide for the evaporator temp sensor.

Heres the coolant temp sensor one http://www.briskoda.net/forums/techn...erature+sensor

11-07-2006, 09:59	#1
MARTYNG Briskodian Join Date: Jul 2004 Posts: 45 Thanks: 0 Thanked 0 Times in 0 Posts	Coolant temperature guage I would appreciate any advice on the following problem on my Y reg Fabia SDI. From starting the engine, the needle/guage appears to be working normally ie climbing from left to right and settles at the vertical position. It never used to move from that position regardless of road and traffic conditions. However, after reaching vertical and settling at that point, it now drops back towards the left. It settles at various points between vertical and the mark midway between cold and vertical I am not a techie but given that the coolant level is ok and I can find no other problems, I suspect that either the guague itself or a sensor providing it with the information is faulty. Your thoughts would be appreciated as to cause, solution and likely cost. thanks in advance Martyn

11-07-2006, 10:26	#2
AwesomeSarah Site Sponsor Join Date: Mar 2006 Posts: 3,698 Thanks: 34 Thanked 166 Times in 147 Posts	Re: Coolant temperature guage Hi Mate I would say coolant temp sensor. They do suffer with these. Easy cheap fix , so could be replacing that to start Hope this helps Sarah

11-07-2006, 10:36	#3
MARTYNG Briskodian Join Date: Jul 2004 Posts: 45 Thanks: 0 Thanked 0 Times in 0 Posts	Re: Coolant temperature guage Sarah - thank you for such a quicky reply.

11-07-2006, 10:56	#4
AwesomeSarah Site Sponsor Join Date: Mar 2006 Posts: 3,698 Thanks: 34 Thanked 166 Times in 147 Posts	Re: Coolant temperature guage No worries mate. Easily done yourself too. Do you know your way round the engine? I have known someone be quoted £100.00 + VAT for this job and it is quite easy to do when you find the sensor. It is located on the thermostat housing. Sarah

11-07-2006, 11:12	#5
ScoobyChris Briskodian Join Date: Mar 2003 Location: Andover Posts: 18,117 Thanks: 15 Thanked 326 Times in 284 Posts	Re: Coolant temperature guage I always assumed this happened because a diesel engine is thermally efficient and I noticed this behaviour on my old Fabia TDI (ie in the winter you could sit stationary in a traffic jam and watch the needle drop).... Under what conditions is the needle dropping? If it's when the engine is being worked hard, I'd say there is a problem but if it's cruising/idling I wouldn't worry Chris __________________ Holding up the traffic in a little Italian..........

11-07-2006, 11:13	#6
MARTYNG Briskodian Join Date: Jul 2004 Posts: 45 Thanks: 0 Thanked 0 Times in 0 Posts	Re: Coolant temperature guage Hello Sarah Other than checking the oil, coolant, brake fluid and windscreen washer fluids, I am a complete dummy when it comes to what's under the bonnet. Unless the sensor is a simple push on fitting without needing to unscrew/unbolt parts of the engine, I will probably have to pay a garage. I don't even know where in the engine to look for it. Unless it is marked in big letters in luminous paint I will probably never find it! Haynes' manuals may be great for mechanics but no good for dummies like me! thanks again for your advice Martyn

11-07-2006, 11:16	#7
MARTYNG Briskodian Join Date: Jul 2004 Posts: 45 Thanks: 0 Thanked 0 Times in 0 Posts	Re: Coolant temperature guage Hello Chris It is dropping when cruising on a motorway and in town driving. It never used to move so it seems odd that it now drops Martyn

11-07-2006, 11:20	#8
AwesomeSarah Site Sponsor Join Date: Mar 2006 Posts: 3,698 Thanks: 34 Thanked 166 Times in 147 Posts	Re: Coolant temperature guage Mine when reaches temp does not move at all idleing or moving it does not move I have the 100PD one So I would think that it is reading incorrectly. I am sure there is a how to guide on this. Check out the Fabia section on here as I think it could be there Sarah

11-07-2006, 13:27	#9
Kerry Briskodian Join Date: Mar 2006 Posts: 97 Thanks: 0 Thanked 1 Time in 1 Post	Re: Coolant temperature guage Sounds more like a thermostat stuck open to me. I've had it on two, or three, different cars. Temp drops at idle and in slow moving traffic and the heater output falls off.

12-07-2006, 11:24	#12
MARTYNG Briskodian Join Date: Jul 2004 Posts: 45 Thanks: 0 Thanked 0 Times in 0 Posts	Re: Coolant temperature guage sounds simple enough for even a dummy like me! Many thanks to all of you for your advice Martyn

13-07-2007, 11:45	#13
Hammett Briskodian Join Date: Feb 2007 Location: Preston, Lancs Posts: 101 Thanks: 2 Thanked 0 Times in 0 Posts	Re: Coolant temperature guage Had this problem with my Octavia (2002 Elegance TDI MK1 110BHP). Engine would warm up to normal temp then guage would just drop then go back to normal after a few mins. Got it serviced a few weeks back and the VAG-COM picked up an error on the coolant temp sensor, so they swapped it (although it doesn't look new to me, probably just twiddled with it until the code wasn't produced). Try just pulling the sensor connector off and checking the contacts. The sensor is located on the side of the coolant reservoir and just pulls of I think (there maybe a clip if I remember correctly). Haven't had any issues with it since.

13-07-2007, 12:09	#15
TDi Vrs Briskodian Join Date: Feb 2007 Location: HEREFORD Posts: 348 Thanks: 2 Thanked 10 Times in 10 Posts	Re: Coolant temperature guage it also sounds like a faulty thermostat to me __________________ 07 Fabia vRS,/// Cruise Control, De-Bump striped, Seat Leon Front Splitter, Seat Sport Front Strut Brace, PD160 Air Intake and Green Cotton Air Filter, Cage mod, Uprated indicator Bulbs and Headlight Bulbs, LED sidelights, Ipod Interface, Jabba Sport ARB, Turbo back, and SportCat Milltek Exhaust, JABBA Sport Custom Remap! 312mm Brakes, Eibach Pro-Kit Springs Privacy tints all round, and Anthracite Octy 17" Spiders and sticky Toyo Proxes T1R rubber! To come Leather retrim, Forge FMIC!

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