Since buying my 2007 2.2 tdi xs the engine temp on the gauge has always been around the mid point on the gauge. Yesterday for some reason I noticed on the motorway the engine temp gauge was reading low, very low, just above the blue mark. Outside air temp was showing as 12 degree. Pulling off the motorway onto country roads and at a speed of approx. 50mph the temp rose to about 1/4 up the gauge, still well below the normal point, in town the temp rose slightly higher, but still below normal, as soon as I accelerated out of town to about 60 mph the temp dropped rapidly. On reaching the destination I popped the bonnet, the top hose to the rad was under pressure, and felt warm, not hot, and not under undue pressure. I released the pressure from the header tank, and there was fluid in there, again not overly hot. The level was slightly down, so topped it up.
This had no effect on the running temp. Returning home it was still the same.

Question is has anybody else had a similar issue. Normally when a thermostat goes the temps go high, as they normally fail closed. This looks as if it is stuck open.

Just changed termostat 07my, same symptoms on winter. Old termostat valve was seized 1cm open, so it was continious flow of cooling water

Thanks, just ordered a new one atleast its not overheating.

I Will Post photos of thermostat when I'm home after duty on nextweek if I find them on pc

Had exactly the same, LR were skeptic so i needed to force them to change it even when it was out of warranty and from my pocket.
It seems that everybody recognize overheating but not over cooling which can cause damage on the long term if not repaired.
Here is my log of engine temp before and after change of the thermostat.

Click image to enlarge

That's good info, I checked the temps with a Bluetooth obd reader on mine and it varied and it went from a high of 157 degree f down to a little over 100 degree f. so would be similar to yours. I was amazed how efficient the cooling is. From being just below normal, within a couple of mins at 60 mph in clear air at 14c it was down to just above cold.
Just waiting for the new thermostat to arrive.

I also had an issue with engine overcooling. When driving at normal speed and normal revs in the city the temperature never got to the half mark, only when I was going uphill or revving the engine a bit.
All got fixed by replacing the thermostat in cooling system.

You can get some strange effects with cooling. I was once driving in very cold weather for the UK (like minus 5-10C) and my car started to overheat. I stopped and called the AA and the operator said that they had had several calls that evening just the same and that I probably didn't have enough anti freeze and was possibly getting localised freezing leading to partial radiator blockage. They advised me to stuff a carrier bag over part of the radiator and let it idle for a little while. It seemed to do the trick and it was ok after that. 3 x FL1 2 manual + 1 auto
5 x FL2 4 manual + 1 auto
Now Discovery Sport P250 MHEV SE

Hello,


has enybody tried aftermarket thermostats like Gates for example?
Any recommendation or experience?
My dealer has quoted 330 € for a genuine one including fitting, kind of too much...

Thanks for sharing,

Pal

Hi Pal,

I bought this one from ebay and so far so good. You can even replace it yourself, it's not very dofficult, but it is very messy job as you have to drain cooling system, and you need a special tool to unscrew these bolts holding the thermostat in place.
https://www.ebay.com.au/itm/182490330545