Oil pan cover / undertray questions (2009 Jetta TDI)

E

evoblade

Veteran Member
Joined
May 16, 2012
Location
Sterling, VA
TDI
2009 VW Jetta TDI
I am considering a Panzer-plate or similar for my 2009 Jetta TDI, any recommendations?
Also, I bought this car used and it was missing the undertray under the engine. This saves me time on oil changes, but does it cost me MPGs or make the engine run hotter? Obviously VW thought there was a benefit to having it. It is worth replacing or not?
 
T

tdiatlast

Top Post Dawg
Joined
Jan 21, 2009
Location
Fort Worth, Texas
TDI
2009 Sportwagen (boughtback); 2014 Passat TDI SEL (boughtback)
I have the diesel-geek/panzer plate on mine (currently $275). I just visited Tim's German Auto for my 80k service, and the tech told me it was the nicest one he's seen. I think $275 is very reasonable for the protection it affords.
MPG change w/o the undertray? W/o wind-tunnel testing, it'd be hard to prove the difference. What it probably does is cut down on road noise, as well as protect the undercarriage from excessive exposure.
FYI, dieselgeek recommends keeping the OEM undertray in place, installing the Panzer plate below it. You can phone them for more information, they've been very friendly and easy to work with.
 
Tdijarhead

Tdijarhead

Top Post Dawg
Joined
Nov 10, 2013
Location
Lawrenceville PA
TDI
2003 TDI Jetta Daughters Car, 2001 TDI Beetle, Wife’s car, 2005 Golf TDI Mine, all 5 spds
Dieselgeek panzer plate, absolute necessity. Plastic oem dust sheild, absolutely useless.
 
Marc_TDI

Marc_TDI

Veteran Member
Joined
Jan 1, 2011
Location
Madison, Wisconsin
TDI
2010 Jetta TDI
From what I've read here on the Forum, the plastic under-tray is also to help keep in heat and dirt/debris/etc out.

As far as 'protecting' our engines, specifically the aluminum oil pan, the plastic tray is USELESS!

The Panzer plate is an addition I've been wanting on my Jetta, I'll probably leave the plastic part on as well.

This adds 10-15 lbs to the weight, the plate does sit a little lower in the nose but not enough to effect mileage.
 
T

tdiatlast

Top Post Dawg
Joined
Jan 21, 2009
Location
Fort Worth, Texas
TDI
2009 Sportwagen (boughtback); 2014 Passat TDI SEL (boughtback)
When I bought mine in 2010, dieselgeek recommended keeping the plastic tray in. Don't know if they still think that's the best.
 
E

evoblade

Veteran Member
Joined
May 16, 2012
Location
Sterling, VA
TDI
2009 VW Jetta TDI
Doesn't sound like this plastic undertray does much then. I won't bother.

Just to clarify, I wasn't asking if my plastic undertray would prevent any need for the panzer plate. :)
 
meerschm

meerschm

Top Post Dawg
Joined
Apr 18, 2009
Location
Fairfax county VA
TDI
2009 Jetta wagon DSG 08/08 205k buyback 1/8/18; replaced with 2017 Golf Wagon 4mo 1.8l CXBB
except, for the 09, the plastic one may have a role in directing air flow from the fan where it needs to be to help cool the DPF/cat when/if you stop during a regen.
 
9

90quattrocoupe

Active member
Joined
Aug 24, 2012
Location
Long Beach, CA
TDI
2010 MV Jetta 6MT, other cars. 90 Audi QCoupe, wife's MV R32, kids' 2009 Jetta TDI
I know this is not about a TDI, but I will throw it out there.

On both the Audi quattro coupe and the Audi UrS4, tests were run with and without the under tray. With the tray installed the cars ran average of 25 to 30 degrees cooler, than with out the tray, when the cars were pushed at the track. The tray controlled the airflow coming through the grills in front.

The tray also cuts down on the under car turbulence, cause by the air flow hitting parts hanging down under the car.

For myself, I run my coupe on track days. One time I had to do a repair, which required removal of the under tray. Since, my run class was coming up, I left the tray off. Car ran about 15 degrees hotter with water and 10 degrees hotter on oil. When replaced, before the next run class, temps were back down to where they were before. Just an observation.

I always run the tray on my VAG cars. I have had 11 of them since 1970.

Greg W.
 
4

40X40

Experienced
Joined
Feb 12, 2006
Location
Kansas City area, MO
TDI
2013 Passat SEL Premium
The factory tray keeps salt spray off your turbo controller as well.

VW usually has has a good reason for its engineering... but WE don't always know what or why they do things in a particular fashion.

Bill
 
B

BITRBO

Well-known member
Joined
Dec 19, 2013
Location
Miami, FL
TDI
'09 JSW DSG
90quattrocoupe said:
I know this is not about a TDI, but I will throw it out there.

On both the Audi quattro coupe and the Audi UrS4, tests were run with and without the under tray. With the tray installed the cars ran average of 25 to 30 degrees cooler, than with out the tray, when the cars were pushed at the track. The tray controlled the airflow coming through the grills in front.

The tray also cuts down on the under car turbulence, cause by the air flow hitting parts hanging down under the car.

For myself, I run my coupe on track days. One time I had to do a repair, which required removal of the under tray. Since, my run class was coming up, I left the tray off. Car ran about 15 degrees hotter with water and 10 degrees hotter on oil. When replaced, before the next run class, temps were back down to where they were before. Just an observation.

I always run the tray on my VAG cars. I have had 11 of them since 1970.

Greg W.
Click to expand...
I run the factory belly pan on my S4 (which is my track car) for this very reason... That, and I have some NACA ducts attached to them for front brake cooling, so it serves dual purpose.

Although the belly pan is currently OFF my JSW, it's only because I've been working under it off & on over the last few months, otherwise I plan to put it back on whenever I get a chance. I also agree that VW wouldn't have wasted time/money on it's design if it didn't have a purpose. Dirt, aerodynamics, and heat/cooling efficiency are my guesses... Zeee Germans don't take a dump w/o a plan you know! (bastardized quote from Red October BTW ; )
 
You must log in or register to reply here.
Top