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-   -   4.2 TDi running temp (https://forum.a8parts.co.uk/showthread.php?t=13722)

goldsax 8th January 2018 08:33 AM

4.2 TDi running temp
 
got my D4 2011 on Saturday.
my previous D3 4.2 Tdi took about 15-20 mins to get up to 90 degrees.
the D4 takes about 25 mins to get to about 80 degrees. it has not manged get to 90 even on a 25 mile drive.
i know it -2c degrees outside currently.
the car heats up the cabin much much quicker then the D3 i had.
normal for a D4 or a thermostat issue?
cheers
raj

Joe2.0E 8th January 2018 06:32 PM

I can't comment specifically on the 4.2TDI but my 2011 3.0TDI D4 does take about 20mins in such cold weather. My old D3 with the 3.0TDI was definitely faster to warm up. The D3 had a webasto fuel heater but the D4 doesn't if that makes any difference.
The D4 also runs at lower revs due to the 8speed auto rather than the 6 speed on the D3. You will notice a significant improvement in mpg over a D3.
The coolant pipework on the D4 has electronically controlled plastic valves that give problems. Some info on these was posted previously on the D4 section of the forum. A VCDS scan should show any faults in this regard.

paulrstaylor 8th January 2018 11:08 PM

D3 had a webasto which speeded up the heat up time by burning fuel.

D4 uses an electric heater, so I guess no hurry to heat up the block!? Probably saves fuel, I can’t say as I have ever noticed, will watch when I drive it next, but that maybe weekend now.....

goldsax 9th January 2018 08:51 AM

many thanks for your reply.
through the years i have moved form a D2 to D3 to D4.
each one much less accessible to the DIYer :(
what you have described with eh D4 engine matches to what i am seeing.
odd that the MPG is worse on the D4
eg. i used to get 34mpg on my 25mile trip to work.
currently i just manage to get 30mpg.
the D3 was 'chipped' though, so was faster then the current D4,
possibly more efficient due to the chipping?

but will get VGCOM on it asap to check any codes.
cheers raj

IT 9th January 2018 02:02 PM

Quote:

Originally Posted by paulrstaylor (Post 136439)
D3 had a webasto which speeded up the heat up time by burning fuel.

D4 uses an electric heater, so I guess no hurry to heat up the block!? Probably saves fuel, I can’t say as I have ever noticed, will watch when I drive it next, but that maybe weekend now.....

^^ This.

Plus the D4 has 8 gears and rarely revs above 2K, makes warming up that large V8 diesel block take even longer....

I noticed it on my D4, but with the electric heaters making warmth straight away i never considered it an issue....


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