So since I changed the turbo on my 2002 TD4 the engine seems to be running slightly cooler.

Normally it sits half way up the gauge with minor ups and downs but since I changed the turbo it sits at about 1/3 of the way up.

Now when I removed the intercooler to clean it I also cleaned all the gunk off the front of the radiator so I guess it's cooling slightly better but other than that I'm at a loss. I've checked for air locks (I lost about a pint of water undoing the wrong bit when I changed the turbo) and all seems good. Lots of flow to the expansion bottle and out of the bleed screw. I also thoroughly cleaned out the inlet path including the EGR and replaced the air filter when I had it in pieces for the turbo.

Mileage is as expected (37 ish around town). Not losing any water or oil.

I have been driving with a very light foot since I changed the turbo as I wanted everything to settle in before giving it any welly but I can't believe that would make very much difference.

All I can think of is that the thermostat is not closing properly but I've never had one seize open, always closed (and we used to just remove them as a temporary fix when that happened).

Should I be worried?

What else can I check?

Fritz

I believe Temp gauges on Freelander should always sit in the middle. The middle isn't a 'temperature' - its a 'range of acceptable running temps' (eg 85 to 100). So if its low - it is low to the range not just low to 'spot on'. Do you have diagnostics kit to plug in and see what the actual temperature is?

Hi

Thanks for the quick reply.

Yes, usually it sits dead centre of the gauge and then fluctuates slightly (I assume as the thermostat opens and close or the fans kick in/ switch off). I think I see your point though; it's not just low as in 80 instead of say 90. It's low as in somewhere below 85 but no real indication of how much lower?

No, no diagnostic kit I'm afraid.

Any idea how bad it is to run it under temperature

Fritz

If it's been twitching around it sounds like it was on it's way out anyway.
Sounds like a failed thermostat/dodgy sender to me...

If it runs cold you can expect higher than normal fuel consumption and maybe VW style emissions.....................

I had a thermostat fail open not out of the realms of possibility!

Most of the TD4 and the R40 which have the same M47 diesel engine the thermostat fails open or at the least open before it should making the engine run cool, you have two options one to replace the thermostat which is a time consuming job, and not that easy to do in the first place, or add an inline stat into the top hose, this can be a 89c gates stat, or an inline alloy stat, the gates is the cheapest around £12-15. the alloy one is about £65
http://www.ebay.co.uk/itm/Rover-75-...hash=item567d8ed117:m:mWNmxypPoRvcAvCPhyqXkJw

Original stat
http://www.ebay.co.uk/itm/ROVER-75-...027723?hash=item43c56c730b:g:SpcAAOxyOlhS9LtF

Gates
'TH01489' and Manufacturer = 'GATES'
http://www.rockauto.com/catalog/raframecatalog.php?catalog=294&partnum=TH01489

I have had a stat fail in the open position and my wife has I do not believe in putting a second stat in some where to cure the problem of the first one, you should change the original one because if it was to fail in the closed position you would be in trouble. then you would still have to do the job.