Model specific boards => Golf mk4 => Golf mk4 TDI => Topic started by: richandhazel on 30 March 2006, 12:20

Title: How to Guides
Post by: richandhazel on 30 March 2006, 12:20
In an effort to try and tidy things up a little, I'm going to put all the 'how to guides' in one place within the relevant section. Here follows a searchable index of all the TDI relevant 'how to guides', feel free to tell me anything that you think would be a useful addition:-

1. EGR and intake manifold removal and cleaning (

2. Avoiding the need for intake manifold cleaning by recalibrating your EGR (VAGCOM required) (

Title: Manifold cleaning
Post by: richandhazel on 30 March 2006, 12:24
Many thanks to the original poster and creator of this great guide for cleaning the EGR and inlet manifold. Had a quick look at mine a few days ago and it looks like it's badly in need of doing so will be carrying this out very soon.

First of all some before and after pics of the sort of gunk that can build up in the EGR valve:-



And this is an example of just how much crud could be restricting your airflow through the intake:-

The guide:-


By: Adam Snow (AKA: Snowball)

Sunday, June 24, 2001


This cleaning procedure was written up while working on my 1999 Jetta TDI MK IV.


Examine your engine, look at these photos and study the locations of the components you may need to move during this maintenance task. Read completely through this guide at least once prior to starting so you are not surprised, or left with questions in the middle of the job!


Start the day by gathering the tools and supplies you will need. Once you start pulling off parts is not the time to learn that you need to make a store run! Get setup in a comfy area. I'd recommend good lighting, and if you are outside consider parking in the shade. Organize everything you need so you can reach it when you need it.


If you have a torque wrench and the manual I advise you to torque all bolts as specified. If you do not have such tools then make note as you remove each bolt. Get a feel for how tight they are. Most of the parts you are working on in this project are made of aluminum and will strip out if you over torque them. Leaving then below specified torque could cause the bolts to loosen, and parts to leak.

Begin by removing the Upper engine cover:-

Note the location of the items listed:

A. Fresh air intake from your air filter
B. CCV unit
C. EGR valve
D. Anti shudder valve
E. Air supply from intercooler
F. Intake manifold

Disconnect the hose leading from the CCV to the fresh air intake. There is a small lip that seals it so pull hard.

Remove the 2 metal clamps that hold the rubber hose from the Intercooler pipe to the EGR. Do not get excited and start scraping at crud out of the EGR at this time. If you loosen the crud now it may easily fall down the intake manifold and into a cylinder:-

Pull the rubber hose off the inlet to the turbocharger. (Sorry I forgot to take a picture of this)

Remove two #5 cap screws that attach the thing (I dont have my manual yet, and am unsure of this units function) shown in the photo from the intake manifold. Pull the vacuum line off of the EGR (mine had a small metal clip that became badly damaged. I do believe the hose will stay put without this clip):-

Remove two #6 cap screws from the exhaust supply line leading from the exhaust cooler to the EGR. Dont loose the thin metal gasket:-

Remove 3 #5 cap screws that hold the EGR to the intake manifold. The bolt in the 7 oÂ’clock position is in a tight location due to a # 6 cap screw holding the exhaust line from the last step to the EGR itself. I was able to remove this bolt with a #6 ball end Allen wrench. Again, do not get excited and start scraping crud out of the intake manifold:-

Remove two #6 cap screws that attach the exhaust supply line to the exhaust cooler [G]. Again do not loose the gasket. Also disconnect the coolant hose [H]. Either clamp or raise this hose above the radiator level to prevent draining of radiator fluid:-
Title: Re: How to Guides
Post by: richandhazel on 30 March 2006, 12:26
Clamp the lower coolant line going to the exhaust cooler. Now remove the smaller coolant hose attached to the top of the cooler:-

Remove three #10 hex bolts that hold the exhaust cooler to the intake manifold. Tie the exhaust cooler so it is up and out of your way:-

Remove six #6 cap screws that hold the intake manifold to the engine block. The 2nd bolt in from the left hit a heat shield on its way out. You may have to bend the heat shield a small amount by bashing it (GENTLY!) with a hammer and long tool such as a screwdriver or punch. Do not loose the gasket as you pull the intake manifold out:-

This is the intake manifold. Make note of where the six bolts are, as you will not be able to see them as you remove or replace them. I do not have my manual yet, but I would recommend the following pattern to tighten these bolts when reinstalling 531246. (That pattern may change as soon as I get my manual):-

The gunk I cleaned out of my EGR valve and intake manifold:-

To clean out this gunk I scraped out as much as I could with hand tools, and a foot long piece of stiff wire. Once the big stuff was gone I used brake cleaner to help loosen the rest. The gunk came out easily as it was rather moist (think of the stuff in a day old coffee filter). If yours is very thick, or hard you may need to soak it overnight, or as some have suggested bring it to a glass bead machine.


The following are pictures of all the tools I used in this project just in case you are not familiar with them all:-

1. Water and towel-less hand cleaner (Use often, no need to put dirty finger prints everywhere).
2. Magnetic parts bowl to hold the parts you remove
3. Hammer to bash (GENTLY) heat shields with (a mechanics best friend)
4. Prying tool (didnÂ’t actually use this)
5. Long regular head screwdriver to be used with the hammer
6. Smaller and well (ab)used regular head screwdriver to use for scraping gunk with.
7. Screwdriver with changeable heads
8. Notepad and pen (so I could write this article)
9. Flashlight
10. Small adjustable wrench
11. #10 open/box wrench
12. #6 open/box wrench
13. Small hook type tool to scrape gunk with
14. Magnetic socket inserts (these can really help you prevent loosing bolts under the car)
15. Magnet on a wand (a mechanics 2nd best friend)
16. Inspection mirror (to find those pesky bolt holes behind the engine)
17. Allen wrench set (metric) with the ball ends
18. Allen wrench set (metric) on a 3/8 socket base
19. #10 hex socket
20. Water pump pliers (used these on some hose clamps)
21. Hose pinching pliers
22. Pliers (again for hose clamps)
23. ¼ and 3/8 drive mini ratchet things
24. ¼ and 3/8 drive socket extensions long and short
25. ¼ and 3/8 drive universal joints
26. ¼ and 3/8 ratchet wrenches
27. 3/8 stubby/flex handle ratchet wrench (this WILL fit those tight places. Highly recommended!)

Your tools will vary, and IÂ’ll leave it to you to decide what of the above tools youÂ’d like to have on hand during this job.

The job was not too bad. IÂ’d rate it a 5 for difficulty (on a scale of 10). The biggest problem IÂ’d expect someone to run into is applying proper torque to the fasteners. The job is not much fun though (took about 4 hours), and you will be spending a lot of time leaning over the car trying to reach the rear of the engine.

Original link:- (

Title: Re: How to Guides
Post by: richandhazel on 30 March 2006, 12:28
Found some more pics of just how dirty these can get:-



and after cleaning:-
Title: Re: How to Guides
Post by: richandhazel on 30 March 2006, 12:29
Whipped my EGR valve off today, just to see how bad mine was:-


Having gone that far, decided that looked bad enough to whip off the inlet manifold and see how bad that was:-


and the outlet:-


I have now scraped off the worst and left it all soaking in diesel. Cleaned up pics to follow
Title: Re: How to Guides
Post by: richandhazel on 30 March 2006, 12:30
Oh and where the guide mentions having to distort the shield to get the bolts out:-

Remove six #6 cap screws that hold the intake manifold to the engine block. The 2nd bolt in from the left hit a heat shield on its way out. You may have to bend the heat shield a small amount by bashing it (GENTLY!) with a hammer and long tool such as a screwdriver or punch. Do not loose the gasket as you pull the intake manifold out:-

I actually found that the first two from the left hit said heat shield so had to gently persuss the heat shield in these two places:-


Oh and the cooler that the guide talks about. Mine didn't have that fitted so made life a lot easier. This may be something that doesn't apply to UK models.
Title: Re: How to Guides
Post by: richandhazel on 30 March 2006, 12:33
Wow what a difference! Can really feel it pulling throughout the rev range now :smiley:

Forgot to take pics of the EGR valve after cleaning but these are the intake:-




Title: EGR adjustment
Post by: richandhazel on 30 March 2006, 12:47
Original link from tdiclub (

Avoiding the Need for Intake Manifold Cleaning - Recalibrating the EGR System - this vehicle is equipped with a CCV (crankcase vent) system and an EGR (exhaust gas recirculation) system. Oily fumes from the CCV system can combine with carbon particles from the EGR system to form a black sticky tar in the intake system. This eventually starts restricting the amount of airflow into the engine, resulting in gradual power loss as the vehicle ages and the intake clogging becomes worse. In rare cases a MIL ("check engine" light) may be tripped, with an intake manifold pressure control code set, but normally this does not happen and no codes are set. Operating conditions, fuel quality, oil quality, driving habits, and general condition of the engine all have some effect on how long the intake system survives before clogging up. It can be prevented and this recalibration is highly recommended for all TDI owners.
A VW specific scan tool such as VAG-COM is required for this procedure. With the engine warmed up and running at idle in neutral with all major accessories such as air conditioning turned off, connect the scan tool cable and start the scan tool software. Select engine control module. "Login" using 12233 as the access code. Select "adaptation" and go to adaptation block 3. Give the accelerator pedal a quick "blip" to ensure that the EGR remains turned on for the next minute while you perform the following steps. Note that the display shows a default adaptation value of 32768 and shows approximately 250 +/- 20 mg/stroke of air intake volume. (If it does not show this, you are either on the wrong screen, or you have an older ECU that differs slightly - see next paragraph.) If all is well, enter 33768 as the new adaptation value, and select "test". Note that the displayed air intake volume changes, usually to about 370 mg/stroke. The specification limit is 370 mg/stroke, so if you want to remain within OEM shop manual specifications for emission control reasons, you might have to enter a number slightly smaller than 33768. (If you don't care about road-legal NOx emission limits then leave it at 33768. [Depending on the usage cycle, NOx at this setting can be increased by as much as 40%]) If all is well and you have a seting that you are happy with which results in an intake air volume of 370 mg/stroke or just a hair less, enter "save". Now your intake manifold either will never clog, or will take so long that the engine will wear out first.

Note for '96 Passat and possibly other older ECU variations: The adaptation numbers are in a different range, and you won't be able to get feedback on what you are doing on the same screen. The EGR adaptation number for a '96 Passat with the original "BK" ECU is 188 rather than 33768 and you'll have to go back to "measuring blocks" group 3 to see the effect before "saving" the new setting.
As for warranty, no one has mentioned any problems nor should there be. This adjustment is also completely reversable should one be concerned.
Most provinces and states that do emissions testing on diesels, just check opacity, so this will not be a factor when testing.

Title: Re: How to Guides
Post by: richandhazel on 30 March 2006, 12:57
Having just cleaned out my intake and EGR I have now carried out this adjustment. With the help of this guide, I had no problem at all :smiley: