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Unlike mk3 and mk4 engines, the intake manifold on the new engines does not suffer from carbon buildup. The biggest reasons are more efficient exhaust gas recirculation metering and cleaner ultra low sulfur diesel (ULSD) fuel. The EGR system has a high pressure side (the one covered with white cloth) that goes directly from the intake manifold to the EGR valve and a low pressure side which passes through the EGR cooler and filter and goes back to the turbo inlet (cold side).
The Jetta/Golf/Audi A3 engine is shown but most of this article can also apply to the Passat TDI engine. The biggest difference is that the Passat engine uses an air-water intercooler as part of the intake manifold. If you have a Passat and can add notes, pictures, or corrections specific to the Passat, please post in the forums to help improve this article!
NOTE: This was performed on my demo engine out of the car. If you can provide additional tips, corrections, or pictures showing this procedure in the car, please post in the myturbodiesel.com TDI forums and help improve the article! This demo engine was partially paid for with site donations, please use the donate button above so I can provide more great DIY!
M8 and M10 triple square (12 point) bit
T30 Torx screwdriver
17mm open wrench
NOTE: The service manual calls for VW tool T40159. It might be possible to get the intake manifold out without removing the fuel rail using this tool but I don't know since I don't have one. It looks like this and can be purchased from vw.snapon If so, it's a required tool since this will save you a lot of work. If you buy it, please post your experience in the forums so I can update this article for future users.
Remove the coolant tube over the intake manifold (2x T30 bolts, black arrows below) and remove the hose clamp on one end. Gently wiggle one end off and plug the ends. Lay the remaining coolant hoses to the side. You shouldn't lose much coolant since the line is elevated.
Disconnect the fuel injector, common rail fuel pressure sensor, and glowplug plugs. (arrow 1 below). The glowplug plugs are pressed on so take not to damage the wiring! Pull from the plug, not the wiring! Disconnect the hose clamps, T30, and 10mm nut holding the fuel return line on (yellow arrow 2 below).
Loosen but do not disconnect the common fuel rail unions (17mm) just enough so that you can move the fuel rail out of the way. It's blocking the upper intake manifold bolts. Refer to 1000q: HPFP common rail removal. You don't need to remove the HPFP, just the common rail and just enough to get to the intake manifold bolts. It will look similar to this. The 2 bolts holding the fuel rail to the valve cover are 10mm 12 point (M10 triple square).
Disconnect the high pressure EGR line (2x 10mm 12 point bolts) and unplug the intake flap connector.
Unplug the EGR and intake valve plugs. Disconnect the 10mm bolt holding the dipstick and the 2x T30 bolts for the intake manifold brace.
Remove the intake manifold bolts (10x 8mm 12 point).
If you need to remove just the throttle valve, it's held by 3x T30 bolts. 2 of them are for the intake manifold brace and the 3rd is the 3rd hole below. The throttle does NOT regulate air to control engine load or rpm like in a gasoline engine. The throttle is used only for EGR flow regulation, throttling air during DPF regen, and during engine shutdown to smooth the shaking when an diesel engine shuts down.
To remove the exhaust gas recirculation, or EGR valve, remove the 2x T30 bolts shown below.
Here is what it looks like separated (click to enlarge thumbnail).
If you ever need to replace the intake manifold swirl flaps, the bolts for the swirl flaps are visible in the above pictures. The motor is on the right side of the picture (left side below). The swirl flaps are in the black intake manifold adapter. At idle and low speeds, the flaps are closed so that all the air is going in through the fill ports and creating very high swirl. At engine start and above 3000 rpm, the flaps are fully open.
When tightening the high pressure fuel lines, make sure they are not bent or under tension as you tighten the unions.
Make sure to fully prime the fuel lines or else the fuel system can be damaged! The HPFP relies on diesel fuel for lubrication and running it with no fuel can result in severe damage! Empty the fuel return line into a clean container while using VCDS to run the electric fuel pumps. This will get most of the air out of the system and fuel rail. Reconnect the fuel return line at the rail. Once the system is closed, use VCDS to prime the lines for at least 60 seconds. Repeat this step at least 3 times. See 1000q: CRD fuel filter change for more details. Any time the fuel system is opened it must be primed!
8mm intake manifold bolts: 6 ft-lb (8 Nm)
metal fuel line unions: 18 ft-lb (25 Nm)
2x fuel rail bolts: 16 ft-lb (22 Nm)
2x high pressure EGR line bolts: 15 ft-lb (20 Nm)
1x oil dipstick bolt: 6 ft-lb (8 Nm)
T30 throttle and EGR bolts: 6 ft-lb (8Nm)
If you have any questions about this procedure or comments on this article for on your Audi A3, VW Jetta, Golf, or Sportwagen, please post your question in the myturbodiesel.com forums or search the site below: