2013 TDCi Engine Temperature Varying

[AlCan]

Hi Guys,

Just back from the cold NZ south, and have really noticed the "dreaded" overcooling problem on my 2013 TDCi. This problem is discussed in various places around the net, mainly relating to MB / DW10B engines, but doesn't seem to appear here. And I can't find the answers I need, anywhere. There is another thread here about engine temps, but it doesn't mention the oil thermostat.

Basically (as typical) the engine is slow to heat up, especially in cold weather, then varies all over the place, below normal temp.

In cool weather, the temperature struggles to get over 70 degrees - i.e the first line after the 60° line. If the engine is working hard, it will get up to normal temperature, just shy of the middle, vertical line, but as soon as it's at reduced load, the temperature drops back again. I know this is normal during a long downhill but not for ordinary highway driving. This doesn't happen on the 2011 TDCi, and sounds exactly like the oil cooler thermostat problem discussed on Talkford and elsewhere.

Do the DW10C engines even have an oil thermostat?

The 2011 is also a DW10C but has hydraulic Power Steering, whereas the 2013 is electric. Can't imagine that has anything to do with it, but as above, the 2011 engine temperature remains almost rock steady once it's warmed up. So, there's something different.

I've searched the net for oil thermostats and only found them for engines up to 2008. P/N 1128018. Looks just like a baby, old-style radiator thermostat housing, but skinnier. Can't find anything for later models. The DW10B oil thermostat appears to live on the front(?) centre of the engine, about where the 10C EGR valve is, but I can't see much else in that area.

Can anyone throw any light on this, please?