Read a lot of threads on this and think I have covered all the base's but just wanted a sanity check before taking a deep breath and doing the thermostat

Basically coolant temp never goes above 70C according to IID and is normally sitting about 65-68. Needle never gets to halfway, usually about "10 o'clock"

Reason for bothering (apart from the engine will never get up to proper temp) is that it is taking ages to heat up the cabin, the air on hot is only luke warm really. this could be an issue with heater valves etc but if the coolant doesn't get up to temp then I am figuring that isn't gonna help with cabin heating up anyway.

I have checked the system for leaks, all OK, bled it and no air locks that I can see - everything seems to to work fine. Today I blocked off the EGR thermostat so that there is no water flow through that either as I had read that could bypass the normal thermostat (although given how little flow goes through there I am sceptical of its impact)

Anyway, just been out for a test and still sitting at 68C

So I am resigning myself to a strip down and replace main thermostat unless anyone has any other suggestion

Cheers,

Paul. 2011 TDV8 AB
2006 TD6 AB (Gone to Wales)

Is it a td6? If so, as you say it's a very common problem and most likely the main thermostat will be the cause.

Yes TD6, just trying to put off the inevitable really  2011 TDV8 AB
2006 TD6 AB (Gone to Wales)

Yeh, I know what you mean. Mine wants doing as well as never goes past a quarter in the winter.

On the bright side overcooling is much better than overheating.

mm289 wrote:

Today I blocked off the EGR thermostat so that there is no water flow through that either as I had read that could bypass the normal thermostat (although given how little flow goes through there I am sceptical of its impact)

So did this job at the weekend, replaced the thermostat. Thanks to Joe90 for his write up

Wasn't too bad a job in the end, probs to 2 1/2 hours if you have the right mix of allen keys, torx male and female, sockets etc - how many various bolt heads can they use on 1 engine!!!!!

Took the plug I had made out of the EGR thermostat loop and fitted a new thermostat. Tested it on my run round the M25 today and needle rock solid at 12 o'clock. IID showing temp maintained between 78 and 88 degrees compared to the 64 - 67 previously.

So looks like it has worked a treat and the interior holds/maintains temp much better - actually turned the climate down today (although the ambient was much higher than recently (10 vs 4)) so it will be interesting to see what it is like on a cold day.

And, as hoped, fuel consumption has improved by at least 2 mpg

Cheers,

Paul. 2011 TDV8 AB
2006 TD6 AB (Gone to Wales)

 .
Experience is the only genuine knowledge, but as time passes, I have forgotten more than I can remember
Volvo V70 P2 2006 2.4 Petrol 170bhp Estate SE
MG Midget Mk1 1962

Previous: L322 Range Rover TDV8 3.6 2008; L322 Range Rover TD6 3.0 2002; P38A Range Rover V8 1999

Fitted a new EGR stat to the TD6 I have been caring for as the temp really struggled to get past the 10 O clock position and there was a real improvement with the needle mainly sitting at 12 o clock and the mpg has improved dramatically.
The old stat was stuck open as I could blow straight through it .
The main stat may improve things further

If you've got IID it is interesting to monitor temps, with the new stat it is now consistently in the 80's once warmed up, interestingly thought it won't warm up at idle/town speeds, needs a couple of good runs to get the temp up.

Paul. 2011 TDV8 AB
2006 TD6 AB (Gone to Wales)

I have a faultmate registered to it at the moment and before i fitted the EGR stat the temps were in the 50s and 60s as it was around freezing outside. i haven't checked it since i replaced the EGR stat but the needle gets up to the middle and stays there most of the time but as you say it is only when i move off it comes up to temperature, sitting at idle it doesn't get that hot.

The temp on my 4.4 stays rock solid in the centre, even when the temp fluctuates between low 80s and when it used to get up to 105 + before i did the 80 deg mod the gauge never moved from centre, which i think is a feature to stabilise the needle between a certain range. Tthe TD6 doesnt do that and the gauge will creep up just past centre when i give it some welly up to the point that it goes into limp mode due to the overboost from the sticky turbo(next job)