MB diesel vs VW TDI - PeachParts Mercedes-Benz Forum

vahe · #1 03-09-2004, 10:10 PM

Yes I know, this is off topic.
How do the VW diesels rate in overal performance and reliability when compared to MB small diesels such as 240D's?

Thanks,
Vahe

1977 240D about 350K

Diesel 924 · #2 03-09-2004, 10:21 PM

VW's have a few quirks like t-belts that have to be changed, they require special synthetic oil and their intakes clog with carbon. Other than that, they are pretty reliable. Apples and oranges really though.

wolf_walker · #3 03-09-2004, 10:24 PM

A more apt comparison might be to the older IDI diesels to the 240D..

#4 03-10-2004, 01:21 AM

Quote:

Originally posted by vahe
How do the VW diesels rate in overal performance and reliability when compared to MB small diesels such as 240D's?

About 23 seconds vs. 11(?) seconds.

The timing-belt, carboning of the intake and possible durability of the 2.0L TDI are what's making me hesitate about getting a TDI as my first *new* car. Dangit, if only I could afford an E320 CDI.

Larry Larson · #5 03-10-2004, 07:11 AM

I drive both. The TDI has much better performance. Overall it's a very reliable engine. The timing belts have been redesigned and are now good for 80-100K miles. There have been problematic relays, and the intakes may clog up unless you disconnect the EGR. Nothing too major, and there's an excellent website (tdiclub.com) with many knowlegeable people who are very helpful. There are people with over 300k miles on these cars. VW dealers offer terrible service, so it's best to find a good independent mechanic. There are guys in the tdi club that travel around and do timing belts and other jobs for members. For long trips I actually prefer my Passat to the Mercedes. It's quieter and much faster and get twice the mileage. Larry

wolf_walker · #6 03-10-2004, 09:17 AM

Quote:

Originally posted by Larry Larson
For long trips I actually prefer my Passat to the Mercedes. It's quieter and much faster and get twice the mileage. Larry

That's a facinating statement on several levels. And I don't doubt it a bit.

I did no know they had the t-belt intervalus up to 80+ now. Must be nice, but it still equates to a yearly thing for me, or darn close to it.

Larry Larson · #7 03-10-2004, 09:37 AM

80K is actually conservative for the new belts. As much as you drive you could easily get by with 100K.

wolf_walker · #8 03-10-2004, 01:36 PM

I got to where I could do the damn IDI's about blindfolded. I came to despise a timing belt, longed for a chain. Then I saw how much work it looks to be to replace the chain and all the tensioners on the 617, and now sliping a belt on in an hour does not look all that bad somehow.

#9 03-10-2004, 01:55 PM

TDIs are wonderful! They're reliable, fun, and quite spunky for such a small engine.

Be aware the the TDI engine is 100% computer controlled. Older Mercedes engines have very limited computer systems, if any at all.

The TDI is chip tunable for more power. A simple reprogramming of the engine's computer ($200) can provide a 40% power increase!

Fuel economy on the TDI engine is stupendous. If you drive like a granny on the highway, you can get 55+ MPG... beat that hybrids. With my lead foot, I averaged 33 MPG over 55,558 miles on my New Beetle (with 5-speed transmission and 115 HP/210 LB-FT torque chip). If you manage to keep your foot out of the accelerator all the time (cruise control on the highway), the chip will give you a 10% increase in fuel economy... how cool is that?

One problem with the TDI is the VNT turbocharger, which if not exercised properly, will clog with soot and seize, causing overboost and catastrophic failure of the turbo and possibly the engine. Be sure to drive it like you stole it on a daily basis... they love being driven hard (high boost, not necessarily high RPMs). As with most diesels, short shifting provides quicker acceleration than shifting at redline.

The TDI is fairly easy to work on... same as Mercedes-Benz. However, you will need to purchase a Vag-Com diagnostic tool to do anything with the engine's computer. http://www.ross-tech.com is the provider for this software. I think it costs $250 now ($200 when I bought it 4 years ago), but it is definitely worth every penny.

Check out http://www.tdiclub.com for more information on the TDI.

Overall, the TDI is much sportier than a Mercedes... partly because of chassis design, partly because of the engine's high torque powerband... especially when chipped.

The one downfall of the TDI is the VW that it comes in. VW is similar to the new Mercedes cars in electrical controls and cheap parts. Quality control and the "dealer experience" also leave a lot to be desired. If you buy a VW, don't buy the extended warranty... it's not worth it. You'll either never use it, or they will deny your warranty claim for some BS reason. Again, search on TDIclub for more information.

If there's anything I didn't cover, just let me know.

Oh yeah, the new style timing belts will last 80,000 miles on an automatic transmission, and 100,000 miles on a manual transmission. This is huge improvement over the old 40K/60K belts.