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Discussion Starter #1
Hi, I have a 03 Jetta TDI. I realize that some smoke is normal but on cold starts, the car runs rough and smokes more than normal. I am thinking that the valve seals might be worn because if the car sits too long, oil drips into the cylinder, and causes smoke. However, the car only has 120,000 miles, so I would not have expected the engine to be worn so early. Once it's warm it runs better and if it's started when warm, very little smoke. Is this the valve seals? Any ideas? I've heard that burning oil is blue, but how blue is blue smoke? The smoke I am getting is not blue like the sky, but I can tell that it's not white like burning coolant either. I'm nots sure if it's black because how dark is black smoke?
 

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If it's really blue smoke it'll be whiteish-blue. Enough blue so that you can see it. Try this: start the car cold and hold a sheet of white paper over the tailpipe. If it collects oil residue, it's probably burning oil. If it's just some fuel that's normal on cold starts. Make sure to use diesel specific engine oil, look through the FAQ section to see some lists. Probably not the valve seals.

Also try looking at the coolant temp sensor. Depending if you have a manual or auto, look for the coolant flange coming out of the head on the driver's side. If you have a manual, there are some glow plugs sticking out of the flange, if auto, no GP. There's a sensor below and behind it, disconnect the plug only. This lets the ECU keep the GP on longer. See what happens. Don't pull the sensor out because coolant will come gushing out, especially if the coolant is warm and pressurized.

And also check the car for codes. Many auto stores will do it for free. The best tool for this is a Vag-Com though , it's a diagnostic cable for VW/Audi that runs off a computer.
 

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Maybe, first check for codes, try the coolant sensor trick to give you longer glow plug ON time. If it's dirty nozzles, you can try to run a can of cleaner like diesel purge through the system and see if that helps. One thing to remember is that unlike a gas car, there's no strong vacuum when you are coasting down with the foot off the pedal. With a gas car, the vacuum can pull oil and cause smoke. With a diesel, there's no strong vacuum in the cylinder so it won't pull oil into the cylinder and cause smoke. When you're boosting, it can cause excess crankcase pressure, which stirs up the engine oil and can cause blue smoke when boosting.
 

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Discussion Starter #5
Also, no oil in the coolant tank either. I was told the coolant is a lifetime fill, should I still change it anyways?
 

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The original fill on the coolant is lifetime...but if it really is contaminted, it should be changed. If it is mixed with non VW/Audi pentosin G12/G12+, etc., coolant, it should be flushed. If you are changing the radiator, etc., why not change it anyways.

Lifetime fills vary by car and fluid and manufacturer, the transmission is a lifetime fill, this has been proven to be completely wrong, it should be changed, both manual and auto. The coolant can be lifetime fill but it can't hurt to change it though.

PS, from what I hear, the TDI can have a leaky head gasket and not have a lot of oil in the coolant, sometimes it will. I don't think this or the nozzles is the issue.
 

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It sounds like you have an idea, but first do a compression test. Make sure to use a diesel compression tester since the ranges are completely different versus a gas compression tester. This will tell you if you have leaky valves, if you have a leaking head gasket, if your glow plugs or injector holes are leaking, or if you have some other problem. You can also get your codes scanned but this won't tell you anything about the valve condition. IMO, it's not a worn engine since that is extremely low for something to go bad.
 

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If it's blue smoke you'll definitely see that it's blue tinted. Black smoke is more misleading because when soot is thin, it has a very light color. First get a compression test and check for any codes. It's possible that the glow plugs aren't going off for long enough, the coolant temp sensor is often the issue here.
 

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Same kinda issue.. was this resolved?

I have the same kind of issue with my 2001 AJM PD 115 Bora (Jetta in US). The smoke is grey/white and also I have some diesel dripping from around the exhaust manifold area, onto the turbo and the driveshaft plastic guard and onto the ground (only while the car is running). I can't for the life of me see where the diesel is originating from, from any angle. The smoke is constant, during idle and obviously increases wildly under any kind of load.

I've put a new head gasket on the car as it was overheating/losing coolant and system was pressurizing, head was skimmed & crack (pressure) tested. All torqued and rebuilt to spec.
New Tandem pump seals also. Fuel lines/pump properly primed.

The timing was slightly off but not majorly, got that set right now.

I also have no DTC's. I have VagCom/VCDS and if there are any results or readings that I can post to help then I can do so.

I've spent hours scanning the internet for answers or hints and tried most fixes/tests.

The turbo was fine and has not been damaged in the head procedure. The EGR was cleaned out and is not sticking at all. The vacuum hoses to and from N75 and EGR Solenoid are all connected correctly as I checked them off against my friends Bora. Looks like I may need to get a compression test carried out..

Any help would be greatly appreciated.

(..and to think I swapped my Subaru Impreza WRX for this car only 3 months ago! Annoyed.) :dunno
 

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If you have fuel dripping onto the exhaust manifold, go to a mechanic and have it fixed immediately before your car catches fire.

If your engine is PD, the fuel lines go through the front of the cylinder head. The only way I can see your leak happening is if there is a leak somewhere in the cylinder head or fuel lines which drip back to the rear.
 

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..

Thanks for the reply chitty. I'm not driving the car and have only been starting it to get the timing set right and to test a few other things as I do them (such as vacuum hoses, new tandem pump seals etc). I've got a mechanic lined up and should be getting it looked into by a profesional towards the end of the week.

Nothing more I can do myself at this point as I have exhausted my own limited knowledge.

I'll post back for others' benefit when I get a diagnosis and HOPEFULLY a fix.

Thanks again.
 

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So, I got the injector seal kit (x 4) this morning, fitted them and reseated the injectors, rocker arms etc and finally the car has no diesel-leak or excessive smoke.. problem solved.. BUT now I have another issue (typical for me, it never rains but it pours).

Anyways, the cooling system seems to be pressurizing way too much and dumping coolant via the expansion tank overflow, the radiator hoses are uber-pumped (pressurized). I've bled the system as instructed numerous times and I am now totally at my wits end with this car.

The upper radiator hose is hot and the lower one that goes to the block via the thermostat is cold. I am am 99% sure there is no air lock and with the head gasket being done (and head skimmed and pressure checked) I am at a loss as to what could be causing it.

Could it be the coolant sensor or radiator thermal switch? I read these can give "overheating" symptoms. If so, is there a "bypass" method to test these theories?

Yet again I am so close, yet so far away, from being on the road again :confused:

p.s. There are no fault codes present
 

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Clogged oil cooler? If a radiator hose is hot/cold, bad thermostat. You say that the coolant system is under pressure? This is really weird if not a head gasket problem. Can you check the coolant reservoir cap for pressure? The way to bypass the sensors is to unplug them. In the case of the coolant temp sensor, the ECU will substitute a fall back value. I don't see how this could cause the thermostat to not open or the hoses to be under pressure.
 

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There is pressure at the expansion (cooler) tank with the top screwed on fully, I can feel & hear it when opened with car warmed up. Oil cooler, hmm.. never thought of that, but I don't think it is clogged or blocked but will check tomorrow when it's daylight.
Thermostat has been changed to a new one and also tried without one in place, still excessively pressurizing hoses at the radiator, top and bottom).
I am stumped also, I know it cannot be the exhaust gasses pressurizing it as I've done the head gasket and had the head skimmed & crack tested.
It was doing this exact thing before I did the head gasket as I seen this issue as a "tell-tale sign" of the HG needing done, but now that it has been done I am lost...

With the car warmed up it takes no more than maybe 15-20 seconds for the radiator hoses to "pump up" real hard.

Other than this problem my car is finally driving perfect, no excess smoke and full power, no limp mode.

One last thing, I read on another forum somewhere that the TDIs have a 2nd valve which works within the cooling system, something to do with a fan and if this is faulty it won't allow the system to operate properly, but then I still don't see how this would pressurize the system.
 

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I've looked for hours on different websites and google searches and from what I have gathered the symptoms of a blown head gasket (even after this has been done) can be given by a faulty oil cooler.

So I guess my next step is to replace this unit at a cost of £102+VAT (17.5%) from Euro Carparts.
I am so fed up with this cars shenanigans. But really I am only left with two possible causes.. A crack in the block OR this oil cooler. Every other viable possibilty has been exhausted.

One question though, if the Oil Cooler is in fact the problematic cause, can and does this cause pressure within the coolant system? If so, then this is for sure my next move. Failing that I think will give up.
 

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I'm not sure but I think the coolant should be able to go around a blocked oil cooler.

If the upper hose is hot and the lower rad hose is cold, that means the themostat is not opening. The only other possibility, and I forgot to mention this earlier, is that the water pump has failed. When the head gasket was replaced I assumed that the timing belt and water pump were also replaced.

Basically, the water pump impeller separates from the shaft. On the outside it spins but on the inside the impeller doesn't move. That could also cause your symptoms like overheating and mimicking the failed thermostat. The OEM ones tend to have a higher failure rate because they use plastic impellers. The fuel leak and pressurization were throwing ideas toward something else.
 

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The timing belt, tensioner, water-pump (with the metal impeller), thermostat, head gasket, head skimmed & pressure checked, head bolts, injector seals (full kit) on each injector, tandem pump gaskets and rocker arm bolts all done and new.
Really the only thing I can think of now is the oil cooler itself, failing this being the cause I am lost. I can think of nothing else that could cause this pressure in the cooling system.
 

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Don't forget the EGR cooler. It exchanges the exhaust gas heat to the EGR gas. If there's a leak you get exhaust gas into the EGR. I would expect dirty coolant though.
 

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EGR is fine thanks, removed and cleaned and checked for full movement.

I put a new Oil Cooler on it today and no change, car still runs fine but the coolant system is still pressurizing. I'm lost.

The top rad hose is hot along with the coolant flange on the block by the tandem pump, the bottom hose from the rad to the thermosat is cold but also pressurized. Thermostat is fine though. The supply hose to the heater matrix only heats via convection, not coolant circulation, the other hose from the heater matrix stays cold also. Would a blocked or airlocked heater matrix cause pressurizing in the hoses of the radiator etc?

Water pump was renewed along with the TB/HG job.

Any further ideas are more than welcome. And thanks for the help so far.
 
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