OT: anyone know anything about TDI's

[kyleN20]

going to look at a VW TDI, its a 1999.5 (so newer style) which i heard have alot of problems, but im still drawn in by the 700 miles to the tank claims. im mostly looking for any known issues with the longevity of the engine, would a car with 199k miles be at the end of its lifespan, or dose it still have some life like a m30

thanks

kyle

[kyleN20]

BTW sorry for posting here but its easyier then joining thr TDI forum and haveing people telling em to use the search button

[Jose]

Kyle,

The tdi's are pretty good solid engines, but seem to have some issues with the wastegate , it cloggs up with the greasier exhaust fumes and stops working propperly creating overboost and therefore activating the overboost protection cirquit resulting in almost stalling the engine, the maf unit is also a weak point on the tdi's from VW and Audi. Elictrical malfunctions are also an frequent issue on the pre 2000 engines and sometimes a hell to find.

[kyleN20]

humm i see, wonder if its worth 3500

[John B.]

We put 70,000 on a 2000 TDI & the only failures were the MAF which went out 3 times in 10k starting at 39k. VW was in denial at that time but 2 years after we sold the car they issued a recall so we finally got full reimbursement for the repairs. The key to keeping the MAF sensor healthy on the TDIs is a clean air filter. Don't even think about using the factory specified change intervals unless they've come out with a much more durable sensor. The timing belt has to be done every 50k on the autos & 60k on the manuals & it's not cheap to have done.

[kyleN20]

im prone to doing repairs myself

[mattyb]

i have only heard good things myself here in OZ. I was actually thinking of test driving a new one pretty soon.

[rob101]

a general note about these types of diesels, I have heard from a number of sources and seen through my work on larger diesels. Recommendations to get the injectors cleaned or replaced at 100 000 km (3000 hrs i have seen on the bigger german diesels which is about 3 yrs). just a thing to think about especially considering the high sulfur in american diesel when compared with europe or australia.

[John B.]

im prone to doing repairs myself

So am I but changing the belt on the TDI isn't a fun job & I didn't have my lift at that time so we farmed it out.

I believe the current owner mentioned replacing injectors around 120k but now that we have the low sulfur fuel over here they should last longer.

[rob101]

So am I but changing the belt on the TDI isn't a fun job & I didn't have my lift at that time so we farmed it out.

I believe the current owner mentioned replacing injectors around 120k but now that we have the low sulfur fuel over here they should last longer.
I think the injector clean/change it still applies with low sulphur, VW wouldn't even bring TDi's into Australia without low sulfur i think high sulphur diesel might cause damage to the catalytic converter/particulate filters that they have in the exhaust.

[John B.]

They brought them in here for years with the high sulfur fuel. Do they use a cat on a diesel?

[rob101]

They brought them in here for years with the high sulfur fuel. Do they use a cat on a diesel?
Yes but they are a new thing, they only came out with the Common Rail diesels me thinks
From Wikipaedia:


For compression ignition (i.e., Diesel) engines, the most commonly used catalytic converter is the diesel oxidation catalyst. The catalyst uses excess O2 (oxygen) in the exhaust gas stream to oxidize CO (Carbon Monoxide) to CO2 (Carbon Dioxide) and HC (hydrocarbons) to H2O (water) and CO2. These converters often reach 90% effectiveness, virtually eliminating diesel odor and helping to reduce visible particulates (soot), however they are incapable of reducing NOx as chemical reactions always occur in the simplest possible way, and the existing O2 in the exhaust gas stream would react first.

To reduce NOx on a compression ignition engine it is necessary to change the exhaust gas - two main technologies are used for this - selective catalytic reduction (SCR) and NOx (NOx) traps (or NOx Adsorbers).

Another issue for diesel engines is particulate (soot). This can be controlled by a soot trap or diesel particulate filter (DPF), as catalytic converters are unable to affect elemental carbon (however they will remove up to 90% of the soluble organic fraction). A clogging soot filter creates a lot of back pressure decreasing engine performance. However, once clogged, the filter goes through a regeneration cycle where diesel fuel is injected directly into the exhaust stream and the soot is burned off. After the soot has been burned off the regeneration cycle stops and injection of diesel fuel stops. This regeneration cycle will not affect performance of the engine.

All major diesel engine manufacturers in the USA (Ford, Caterpillar, Cummins, Volvo, MMC) starting January 1, 2007 are required to have a catalytic converter and a soot filter inline, as per a new DoT legislation

[kyleN20]

i think im going to go look at it today