Passat 2.0tdi dsg 170 starting problems from cold

[DMitch16]

If there has been previous oil / fuel contamination as you mentioned previously then the whole system from the fuel tank forward through the feed pipes and back down the return to the tank may have a decent coating of oil. Extreme cases have warranted a clean of the entire fuel system tank and all. Cracked heads usually show themselves via a drop in the coolant level without there seemingly being any external leaks. Continued white smoke from the exhaust when the car is up to temperature is also a give away as is the frequent failure of EGT sensors which don't like to get wet in the exhaust system / DPF.

I have had the infamous BMR cracked head and I can see why some may have suggested this but mine never had hard starts or lumpy running even when the head was cracked.

If the car runs very well at any other time then it's unlikely to be a cracked head. Most of the coolant leakage I suffered was overnight when the cracks were at their widest. Heat when running expands the metal which closes the cracks. VW state that if the cracks are below a certain limit there is no need for any repair and the car can continue to be used normally. In fact a great deal of VW engines of the B6 period are operating fine with very small head cracks (Golfs, Jettas, Passats etc.). It's only a problem when they expand further.

It could be a gummed up slow EGR as once the car is hot the EGR tends to close. The EGR on start up usually cycles around 30 to 40% when the engine is cold.

[scanny1]

Well when I replaced the tandem pump last year it's had a thorough clean I drained the tank cleaned the tank and best I could cleaned out the fuel hoses ,maybe Egr clean might be worth a try as I'm having nothing coming up on the vcds ,is it easy to take off and clean cheers

[DMitch16]

If you can do all that to your fuel system then yes the EGR will be easy enough for you to remove. As you have the same year as mine the layout will be similar or even identical.

I do it this way...

Remove air box and air intake pipe work pre air filter (no need to remove last pipe to turbo but the spring band clip is a pain). Locate EGR pipe which bolts at rear of engine above gear box bell housing and slacken the 2 bolts. Remove front boost pipe from EGR assembly (anti shudder valve and EGR unit mounted as a single unit beneath inlet manifold) and undo the 2 EGR pipe bolts at the front and remove. There should now be enough movement for the EGR pipe to be moved out of the way of one of the torx bolts (there are 3) which hold the EGR and Anti Shudder flap units to the manifold. One of the 3 is at the rear, very long and goes through both units. Once the 3 bolts are removed the whole unit should come away but ensure the electrical connector has been disconnected first. Unless you have a new seal I would not recommend separating the 2 units and when cleaning with brake or carb cleaner cover the electrical connection. Ideally new gaskets should be fitted to each end of the EGR pipe. Reassembly is the reverse of removal.

[scanny1]

Not yet taken the egr valve to clean waiting for gaskets.but now once the engine is at temperture its struggling to turn over really slow the battery's fine 12.6v the starter motor seems OK in the morning

[scanny1]

Could it be coolant temp sensor tried looking for it to disconnect can't find it ,usually on a water pipe but not in this model

[DMitch16]

There are 2 temp sensors on a 2007 year 2.0 litre Tdi. One is near the thermostat housing behind and to the right of the alternator and the other at the bottom of the coolant flange connector pipe under the tandem pump.

[scanny1]

Cars now at the garage seems to think the speed sensors gone wait and see

[scanny1]

What a pain the garage can't get the sensor off so gearbox has to come off for a 70 sensor

[FLAPPERJACK76]

Hmm...you can get off but it's a miserable job. Take the intake pipe off and the oil filter/cooler off.

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[scanny1]

There telling me the gearbox has to come off apparently bolt head has rounded off