Technical water temp problems. pleaaseeee help

[wizard74]

Hi guys, New here and have read through all the posts here but not found a solution.
my multipla 1.6 has a dodgy temp gauge,
after driving for 5 mins from cold it changes from 4 bars to 5 or 6,
Never gives red warning light,
When I park and idle it drops back to 4 usually.
I noticed tonight that when I was parked up and had 4 bars once I selected reverse and out my foot on the brake it went back to 5 bars.
the dash seems the dim slightly when the brake is pressed.
Also sometime the temp gauge goes completely blank.
Sorry for wandering but really hoping one of you guys can help me out

 

[BikeDoc]

Water temp problems . . .

Hi, welcome to the Multi-Madhouse!

It's unlikely to be the gauge (display) itself, it will more-likely be the temperature sender that gives the signal that's at fault.

The temp display blanking is odd, try pulling the connector off the sender with the engine running and warm, see if the display goes off then.

Next time it's showing 5 or 6 bars, whip the bonnet open and kop a feel of the coolant hoses, at 'normal' running temperature they should be just too hot to hold onto for more than a second or so.
If it's really running over-hot, you won't be able to hold them at all.
Go carefully, just 'pat' the hoses at first to test the temp.

I would think that the fan(s) would come on if it was actually at 6 on the display.
If you have Air-Con, hit the switch when it's showing 6, that'll bring the fans on, see if the display drops.

The dimming dash when the brake pedal's pressed sounds like either low voltage from the Battery (bad connections or earths possibly), or a partial electrical short somewhere.

Multi's are prone to throwing up spurious warnings/readings unless the battery is in fairly good condition and fully charged.

Get it checked, most tyre/battery places will do it for free.
Winter puts a lot more load on the electrics, lights, heater fan, heated rear screen etc.

 

[wizard74]

Thank you so much for your reply,
I went for a drive today to try to narrow it down a little, I plugged in my obd reader and left it running so I could see live readings.
the temp never goes above 204f or 97c.
the fan is kicking in and the pipes feel normal, not incredibly hot. Not loosing any coolant either.
the temp gauge went up to 5 bars and then 6 and then disappeared again.
while it was doing this the temp readout on torque remained constant.
when I got home and parked up it was on 6 bars while idling but when I switched off headlights it dropped by one bar, when I switched on headlights it went up by one bar ! I did this several times and it happened every time ! I'm thinking of taking out the battery and giving it a full charge to see if that alters anything

 

[BikeDoc]

Water temp problems . . .

Looks like it's just an indication issue then, but it's not nice to have it showing hot, even when you know it's not actually over-hot.
It'll be that one time you ignore it that it really is overheating . . . :bang:

As I mentioned, most tyre/batt places will check a battery for free, I'm thinking Kwik-Fit/Euromaster/ATS/Halfords, try them first.
If the battery is more than around 3-4 yrs old, it's probably due for replacing.

If you do a lot of short journeys (<8 miles or so), that can also tire-out a battery prematurely.

Make sure it's the correct Amp/Hour rating too, it's not uncommon for an older vehicle to have a lower-rated (cheaper) battery fitted by a previous owner (or unscrupulous garage).

 

[wizard74]

Thanks a million, will try that and report back

 

[wizard74]

Still having my problems here, I'm wondering could it be a bad earth somewhere ?

 

[varesecrazy]

quite possible.

clean up connectors to engine temp sensors too.