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MG MGF Technical - temp gauge on cold

Hi All
Wonder if you can help/is it serious?
We have a red 98 vvc mgf which is beautiful!
Lately i have noticed the coolant temp gauge not climbing to the normal half but staying on the cold or just above during normal or hot driving (even when ticking over on the drive way?)
Is this serious (HGF) OR maybe just a sender/sensor gone?
Hope you can help.
TT
tony thomas

1: Does the heater blow hot air?

2: How long do you leave it idleing for?

3: After a while does the fan come on?

1&3 = faulty or dirty blue or black sensor (given some movement on the gauge)

1 (depending on speed, but mostly cold) & 2 (<15 mins): faulty thermostat.
Will Munns

Also if heater only blows luke warm then stuck thermostat, but I would check all Wills suggestions first.
You have checked there is water in the system !
M
Mike (Mersea)

Get it checked right now
dont delay
dont drive it!

Neil

Thanks Will etc
1 Yes the heater is hot
2 15/20 mins today, the gauge did move above the cold but no where near half way like it used to as soon as you went about half a mile and the dial would stay there.Now you can drive around town all day and the gauge hardly moves at all?
3 Have not heard the fan come on
There seems to be plenty of water, the header tank is as it was (full)

Sorry to be paranoid but i also own (last 3 years) a 620 ti turbo that is prone to HGF and water temp probs so don't want to pay out again for repair work just yet!!!(Like a sucker i love it and will not sell it)
Do you think the mgf prob is just thermostat or sender?
Is it ok for the wife to use it for day to day use in the mean time? before i get it checked out.

Many thanks
TT
tony thomas

Right, looking good

If the gauge moves up to 'n' and stopsbut the heater still works the same, and the gauge doesn't fall below n as you drive then it is almost defo the sensor and as such perfectly OK as this sensor is used for the gauge _only_.

Get yourself to maplin or maplin.com and buy 'contact cleaner spray' (£2)

with spray in hand remove the engine cover panel on the parcel shelf, in the centre at the front you should see an elbow bolted to the head where the pipework joins.

you should see a brown sensor and either a black or a blue sensor(I think black for you)

the black sensor has a oblong boot with one wire.

squeeze the plug on it's longer sides and pull, it should come very easily, if not then squeeze harder, you should be pressing against a metal clip.

With the boot off spray the sendor contact and the boot contact liberaly with contact cleaner, plug and unplug several times.

Repeat for the brown sensor as a precation because there is no warning about this one except when the fan doesn't come on in mid summer!!

Before putting it back together run the engine for 10 mins or however long it takes to get up to centre. If it doesn't then you will have to buy a new black sensor (~£15)
Will Munns

Thanks Will mate!
Will try that this wEND will let you know what happens .
Cheers

TT
tony thomas

Great detailed description from Will.. as usual :)

Find some pics about the matter at
http://www.mgfcar.de/coolant_sensor_change/index.html
(Notice the reffering to the other brown coloured sensor on site. You need to access the black or may be blue coloured)

P/N of water temperature gauge sensor
The black is GTR 207.
The newer blue coloured is GTR240 or
YCB100370.

Might me of interest depending on how far you like to jump into the _technology_
http://homepage.swissonline.ch/TomsSeven/Main/CTS_Meter_logic.htm

... last immidiately advise while you are on the matter:
Change under bonnet Fuse No 2, the second from direction wing, from green 15AMP to yellow 20AMP.
This will prevent from a blown fuse due to a sticky front fan at any time. The 20AMP is installed already at newer MGF.

Rgds
Dieter
Dieter K.

I dont think the second link is anything to do the the F, for a start it lists diffrent gauge readings in degrees, rather than the three options our gauge shows...

Measured temp Gauge temp
.....0............cold..
....10............cold..
....20............cold..
....30............cold..
....40............cold..
....50............cold..
....60............cold..
....70...........normal.
....80...........normal.
....90...........normal.
...100...........normal.
...110........off scale.
...120........off scale.
Will Munns

This thread was discussed between 16/03/2005 and 17/03/2005

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