Ford Galaxy - Intake Manifold Cleaning (Mk2)

[Mirez]

Galaxy TDI ââ,¬â€œ Intake Manifold Cleaning Removal and cleaning of the intake assembly. (VW PD Engines) 

In common with a lot of diesel engines the Galaxy has an EGR (Exhaust Gas Recirculation) system and CCV (Crank Case Ventilation) system. 

The EGR system: Designed to reduce emissions by redirecting a small proportion of exhaust gases back into the intake for a second combustion. This has the effect of raising the intake air temperature and subsequently the effectiveness of the combustion. The EGR system functions mainly at low power requests by the driver.

The CCV system: Designed to vent out air displaced by piston movement and thus aid power and economy. In high compression engines (most modern diesels) small amounts of oil pass by each cylinder during its cycle, combining with the fast moving air to form oil vapour which is then passed out of the engine via the CCV. The CCV on the Galaxy is fed back into the air intake just up from the turbo, the result being that the oil vapour enters the intake tract and, as it cools, turns back into oil coating all the components on the way

Both these systems work well to do the job they were designed to do however as the oil vapour from the CCV system mixes with the sooty air from the EGR system it forms a sticky sludge that over time builds up inside the intake system and subsequently restricts airflow. This build-up can have a dramatic effect on engine power, response, idle noise and has been linked to increase turbo wear.

The EGR Heat Exchanger is designed to lower the exhaust gas temperature and raise the coolant temperature. Itââ,¬â,,¢s bolted to the back of the intake manifold. 
Minimum Requirements:   
Allen Keyââ,¬â,,¢s (5mm, 6mm)
16mm Spanner/Socket (2004>6 cars)
Cleaning equipment: Wire wool, steel brushes etc
Manifold Gasket
Hose clip removal tool (Large pliers etc)

Additional Recommendations:   
Allen Sockets (5mm, 6mm)
Ferric Chloride
EGR Gaskets: (EGR Valve to Manifold Gasket, EGR Heat Exchanger to Valve Gasket, EGR Joint Gasket x 2 & EGR Intake to Heat Exchanger Gasket)

General Information:   This is a reasonably strait forward task but time consuming. It took 6 hours work to complete but if the manifold was nicely accessible it would have taken no longer then 2 hours. Since a lot of the work is done without sight and with restricted access this adds considerately to the time.  The process below details how to remove the EGR valve and Inlet manifold. The heat exchanger is left is situ for this task as removing it would require draining the coolant system ââ,¬â€œ however the restricted room also adds to the time.

Location: (Engine cover already removed)

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Quick Strip Down in preparation : 
Remove Engine Cover - (Pull upwards) 
On 2004> Remove windscreen wipers and detach scuttle assembly
Remove air box assembly ââ,¬â€œ One allen bolt, undo the pipe clip after MAF
Remove intake pipe ââ,¬â€œ Remaining one clip on turbo downpipe
Remove bulkhead extension panel ââ,¬â€œ 2 nuts, 1 bolt and weather seal 
Remove the MAP section of pipe work ââ,¬â€œ one clip, one giant E clip (top) - cover the intake pipe with cap/rubber glove etc to prevent ingress

Ok, so we are now ready to start the real work! The next task is one of the more awkward ones, Removal of the EGR Heat Exchanger (HE) output to valve pipe. Its 4 allen bolts in total taking care to recover the gaskets as the pipe separates:

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With this pipe removed you now have access to the 3rd retaining bolt of the EGR Valve which is next to be removed. Disconnect the two vac pipes going into the valve (red) and the bolts (green) ââ,¬â€œ again they are tricky to access. Lift out the EGR valve assembly.

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The valve assembly is where the mixing starts, so donââ,¬â,,¢t be surprised to find some standing oil on the right side and a very gummed up left side. Remove the turbo downpipe retaining bolt (red) from the side of the manifold and then the three bolts (blue) that hold the EGR cooler to the back of the manifold together with the two bolts holding the final piece of EGR pipe work to the cooler.  These are easier to see but again, photography wasn't easy so this is the view of the back of the manifold assembly, referenced with the HE view from earlier.

With the HE now free to move, the final stage is to remove the 6 allen bolts that hold the manifold to the head (Orange arrows). Again we need to recover the gasket at this point ensuring if you plan on reusing it that you know which way it faces the block. Note, where oily residue has been leaking from the EGR system down the back of the manifold and also where the intake gasket appears to have been leaking between ports 2 and 3.

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With the manifold removed itââ,¬â,,¢s now time for the cleaning and de-gunking of the assembly. Itââ,¬â,,¢s easy to forget this stage later on so start by using a clean rag to wipe around the back of the cylinder head against where the gasket will seat. Care should be taken that nothing falls into those inlet ports including debris and solid particles from the surrounding area but a clean surface is essential for a good seal when the unit is refitted. The car this manifold is from is a 2003 TDI with just 70K on the clock !

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The two photos above show the intake to the manifold before and after, you can see the volume of contamination thatââ,¬â,,¢s built up here which is restricting airflow. Below is a closer photo of the same intake with a small section scraped away, it aids to show just how thick the sludge is measuring at 6mm thick at this point. To the right is the port outlets which have faired a little better but the build-up here is still over 2mm thick ââ,¬â€œ more interestingly is that the build-up is less on ports 3 and 4 which could have given an imbalance in intake air and potentially the cause of the increased idle.

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Cleaning out this assembly is a messy old affair so be warned! Use a screwdriver to scrape out as much solid debris as possible and then the wire brush to get back to metal. Try and get into as many areas as possible but be careful to avoid doing damage to the mating surfaces.  Experimenting with various chemicals found that Ferric Chloride was reasonably effective at eating through the left over debris but if you do plan on using it remember that its an acid/etchant so protective equipment MUST be worn.  Mix up enough solution to allow it to be lightly poured into the upturned manifold and then, using a paintbrush, work it over the remaining surfaces. Leave it for a few minutes to work before washing out and repeating again.  Remember the used solution must be contained and disposed of correctly. Most local recycling centres will take it if properly marked in their household chemicals section.  When cleaning the EGR valve, care should be taken to avoid damaging the rubber seals and diaphragm so use any chemical sparingly.  Once complete the manifold, valve and pipe work can be reattached to the vehicle but must be fully dried! When re-attaching the manifold ensure a new gasket it used, this one is a ââ,¬Å"crushââ,¬Â type and can only be used once. In practice the EGR gaskets are normally ok to be reused but it would be prudent to change them at the same time.

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This article is also available in PDF form attached - Contains information on disassembling, cleaning and rebuilding the intake manifold assembly and EGR system on the VW PD Engines (All Mk2 Galaxy Diesels)

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