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Discussion Starter #1
I just bought a 2000 2.5 TDI and while it's generally very good I have a couple of issues...

1. Poor cold starting. I have to engage the glow plugs at least 3 times and then churn it over quite a bit to start. Once running it seems to run absolutely fine. I tried changing the glow plugs after checking for power to them.No change.

2. The temperature gauge doesn't move. This is backed up by cold air from the heater. If I drive for long enough (say half an hour) it suddenly jumps up to 90 and there is heat. I have replaced the thermostat (crusty but not jammed open) and done my best to bleed the thing. Again, no change whatsoever.

Any thoughts appreciated.
 

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My first thought was the thermostat until I read you changed it. I had a problem with mine where the gauge was not reaching 90 and it always previously had. I found the thermostat broken on one side so it was constantly slightly open. New stat and it was fine again. My next thought for yours could be water pump not pumping properly or maybe there's a blockage somewhere in the system as you say the thermostat was a bit crusty. Maybe there's some crud built up somewhere restricting the water flow. I had no problem with crustiness on mine, in fact it looked new inside there.

The cold start issue you have could be diesel pump timing. Absolute swine on the TDI if it's not set correctly.
 

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2.5 TDi doesn't even need the glowplugs.....mine will still start at -10 -20C (but with a longer ctanking).

Most common problem is the timing.
You need VCDS on it and check the timing at the correct temperature.
Should be at 55 (but 50 - 60 is OK as they aften wander a little).

Typical for a 2.5 TDi to NOT warm up before 30 mins....unless you have the extra Eber heater under the bonnet. (And a WORKING one!)
The temp guage is ridiculous on these engines....it's fed from the ECU, not just the sensor.
 

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Discussion Starter #4
Ok - thanks. I just went out to start it and I think I was lucky it started. Lots of cranking and the street is full of smoke!! Runs great once it is going.

I have VCDS on my laptop but can't find the lead. Haven't used it in years. Once I have resolved that minor issue I'll have a go at it :)
 

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I'd say it is the timing by the sounds of it. I've not quite had the same issue but heard of many that have. Worth checking anyway if you have VCDS.

I've just ventured into VCDS myself but not registered it yet so limited to what I can see on it but have used it to clear a fault code which I had.
 

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2.5 TDi doesn't even need the glowplugs.....mine will still start at -10 -20C (but with a longer ctanking).

Most common problem is the timing.
You need VCDS on it and check the timing at the correct temperature.
Should be at 55 (but 50 - 60 is OK as they aften wander a little).

Typical for a 2.5 TDi to NOT warm up before 30 mins....unless you have the extra Eber heater under the bonnet. (And a WORKING one!)
The temp guage is ridiculous on these engines....it's fed from the ECU, not just the sensor.
Mine heats up about 8 km without using the Eber. With the Eber, I need about 4 km at 0 degrees.
 

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Discussion Starter #8
So... got VCDS-Lite hooked up. Result was around 13 - "too retarded". At least it was on the graph.

I'm a little confused. I have read about making tiny adjustments to the pump itself and also adjusting the belt tensioner to tweak the timing. Which am I in the realms of - if that makes sense?
 

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Either will work, adjusting the belt tensioner is probably a bit easier, just do a little at a time and recheck
 

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Discussion Starter #11
Update...

So after a night out in the cold it started much better this morning. It's still not what I would call fantastic but it felt like it was probably going to start rather than it probably wasn't. Maybe 10 seconds cranking.
 

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I would say check your glow plugs and do a compression check... Worn nozzles will also lead to poor starts and perormance...
 
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