Seat Leon Essential Modifications - Diverter Valve Fitting Guide

All cars have their weak spots, thanks to manufacturers cutting corners to save a few pennies here and there. The 1.8 litre 20 valve turbo lump is a popular and robust unit, let down by a handful of cheaply made ancillaries.

The first of these cheap ancillary parts to be replaced has to be the diverter valve, also referred to as the dump valve.


The technical bit...

The diverter valve is vital in preventing compressor-stall when the the throttle plate is closed, due to high-pressure air getting trapped between the throttle and the compressor side of the turbo and sending a pressure wave back towards the compressor. This can cause the turbine to rapidly slow down or stall completely and puts severe stress on the compressor.

This situation can easily happen when changing gear while the turbo is under boost conditions, as most people will temporarily lift off the throttle then reapply it. If the turbo loses speed between gearchanges there will be a delay while it spins up again - better known as turbo lag.

The major problem with the standard plastic diverter valves is that they contain a diaphragm which can eventually perforate due to the high-pressure, high-temperature air they are continually exposed to. This causes a continuous loss of boost as high-pressure air is allowed to bleed away back into the intake, and this is why any enthusiast should change the original valve for a more robust unit.

Note...

Replacing the diverter valve is not strictly a performance modification and will not increase power output from standard form. The whole point is to change it for a more reliable (and serviceable) unit which will then allow the rest of the system to run as it was intended, free from any losses caused by high-pressure leaks. Having said that, if your diverter is leaking you will immediately feel the benefits from the new valve as it reclaims lost BHP.

Also note...

The alternative to a diverter valve (also referred to as a recirculating dump valve) is an atmospheric dump valve, the kind that gives that distinctive "pshhhhhhht!" sound when operating. These can cause various problems for the engine management system due to the fact that the ECU has measured the incoming volume/mass of air and calculates the amount of fuel to inject based on this. If air is suddenly removed by venting the excess out of the system, the engine will suddenly have a fuel-rich mixture which can trigger engine management warning lights and limp-home mode to kick in.

For a simple life, stick to the original diverter type valve.


What you will need...

A replacement diverter valve (obviously) - the Forge Motorsport DV007 is the valve of choice for many as it fits very well, is well made, is serviceable and has the backup of a company renowned for its excellent after-sales support. Another popular choice is the Bailey DV30.

A flat-head screwdriver, 4-5mm across.

A large cross-head screwdriver.

Jubilee clips, 2 large (genuine Jubilee "1A" types are ideal at 22-30mm range).

Either a small Jubilee clip (10-15mm range) or a fuel-hose type spring clip (Mikalor 14mm is perfect fit).

Long-nose pliers if you go for the spring clip option.


Step 1. Remove the main engine cover. Use the large cross-head screwdriver to turn the cover retaining clips (arrowed) through 90 degrees then lift the cover away and put it safe.

Step 2. Remove the original diverter valve. The valve is located near the air filter box (replacement valve fitted in the image for clarity)...

 

And here's the original item in all its glory...

 

Here's where you need the smaller flat-head screwdriver. Insert it into the single-use clips (arrowed) and keep turning the screwdriver until the clips have enough slack so they can be moved out of the way...

 

Once the clips are slackened pull the old valve out and put the new valve in, using the large Jubilee clips on the inlet and outlet. It will end up like this...

 

Here's where I chose to use the spring clip (fuel hose type) rather than a Jubilee clip (arrowed below). Access is a bit tight for even the smallest Jubilee clips and the spring clip looks fairly "factory original", not that anyone will ever know if you refit the engine cover...

Now you see it...

And now you don't...

Conclusion...

Replacing the diverter valve is an easy job and is a must for any enthusiast. My old valve definitely was leaking boost, which could be heard when the driver's windows was down. The turbo would spool up, hit a certain pitch and then drop down to a lower pitch. With the new valve the turbo hits a certain pitch and stays there. The midrange feels stronger and more flexible as a result, and the upgrade is money very well spent. Finally the replacement valve is just that, a high quality replacement and not a performance enhancing modification. With this in mind you needn't feel too guilty about not declaring it to your insurance company should you happen to forget...

DubSteve

Seat Leon Leaking Door Seals Repair Guide

Leaking SEAT Leon 1M and Toledo doors? Welcome to the club. If there's a problem with wet carpets it's usually because of the VAG group's decision to seal the door inner carrier (which holds the window mechanism, locks, speakers etc.) with a foam strip. These foam strips eventually break down near the speakers and allow water to run inside. A few cars were recalled but most will suffer this issue eventually. VAG changed over to butyl rubber sealant as a result of this, and it's this that we'll be resealing the doors with.

There are two ways of tackling the problem, one is bodging it and the other is doing it properly which only takes a little longer. Here's how to do it properly. Overall the job is very easy and will take maybe 1/2 an hour per door, less time once you know how it's done.


Before you even think about tackling this, get onto eBay and buy the following items.

1. Search for "pry tools", the iPod/mobile/laptop opening variety. Buy some that look like this...

2. Buy some "Golf trim clips", there is every chance you will bust a couple unless you are very lucky. These are the ones you need...

3. Search for "butyl sealant strip". I bought the 6mm round stuff - 8m roll, enough for all four doors, and not too thick to be a problem when reassembling the door's inner carrier. Cheaper than the VAG branded stuff at £7.49, delivered. Looks like...

Once the postman's delivered your bits, get the following tools together. Large Philips screwdriver, T20 Torx, sharp knife, plastic pry tool, and a 10mm socket. A flat-head screwdriver and a pair of wire cutters may also come in very handy...

While the job can be done solo an able-bodied assistant will make certain tasks much easier. Assistance while disconnecting/reconnecting the door-card electrics is highly recommended. Having someone around to hold the roll of butyl sealant while you feed it in will also be a huge help.




Step 1. Remove the grab-handle cover. This is why you bought the pry tools! While you could just use a screwdriver instead of the pry tools you will most likely chew up the handle plastic while trying to pop the cover off. The pry tools do the job without totally knackering the cover. Start at the lowest point of the handle (upper side) with the pry tool and wiggle it until you have about 1mm of gap. Repeat on the lower side, then back to the upper and keep wiggling until the cover pops free...

Pull the trim from the lowest point...

And finally pull on the opener so you can get the handle cover off...

Step 2. Remove the door card. Before proceeding, wind the window down all the way. The front door has 2x T20 Torx screws at the bottom which need removing (none on the rear doors). The grab-handles are secured by two large Philips screws (arrowed)...

Now pull on the door card from the bottom. If you do it slowly and firmly then trim retaining clip casualties should be kept to a minimum. Once all the clips have popped free you will be able to lift the card slightly and move it clear of the door frame. Have an assistant hold the card while you disconnect the various wire connectors. All the connectors have one or two squeezy retaining clips. Don't be hasty and you'll have them off in no time. The door opener is fairly simply to unhook - pull on the cable outer, away from the handle, and lift it over the plastic bracket. Once you have all connectors off you should see this...

Step 3. Loosen the carrier plate. Take your 10mm socket and remove all the 10mm bolts except the two that are arrowed below. These two remaining bolts should be wound out nearly all the way, allowing you good access to the rear of the carrier without completely removing it. You could remove these last two bolts but your assistant would then have to hold the carrier while you fit the sealant strip - but you really need your assistant to hold the roll of sealant so leave the bolts in position...

Front door...

Rear door...

Now you need to break any seal between the door frame and the carrier. The best way to do this is with the large flat-head screwdriver you hopefully have ready, resting on a towel so you don't kill any paint...

Here's where my seals disintegrated, seem to be very common failure areas. Affected areas are between the arrows...

Front door...

Rear door...

Now the carrier is loosened, get to work on that seal and show SEAT how it should have been done in the first place! Start wherever you like and pull the old seal off slowly. I made an exception on the rear doors as I couldn't get as much clearance behind the carrier as I wanted and so left some of the seal in place. The next step will show what I left in place. It's adhesive backed but will come off cleanly if you are lucky. I wasn't, and was left with a few inches-worth of rotten seal on each door that had to be scraped off. I used my trusty T20 to get into the channel where the worst of the remaining rotten seal (and brown gunk) was hiding. You don't need to get the surfaces surgically clean but they do need to be dry and free of as much of the old seal and gunk as possible.


Step 4. Fitting the new seal. See the pics below. I started where I did on the front door (arrowed) due to the electric window wiring loom getting in the way. It seemed like a good starting point and worked well for me. Slowly feed the butyl sealant strip into where the old seal lived.

Front door...

As mentioned in step 3 I didn't replace the whole seal on the rear doors due to access. Here's what I did replace...

Step 4. Put it all back together. Self explanatory really. Replace any trim retaining clips that broke. Here's where I used the wire cutters to grip and wiggle free any snapped clips or clips that came off the door cards and could be reused…

And after all that, only one bust clip per door. Not bad going!

Once you've done one side the other will be a piece of cake. I'd read many online guides of varying complexity and clarity but still wasn't sure how difficult it was really going to be. Some guides suggested a need to remove windows glass or the carrier plate itself, but it's really not necessary. As it is, the job isn't difficult at all. All four doors can easily be done in an afternoon once you have everything prepared. One final note about the butyl sealant strip, it's pretty sticky stuff (even more so when warm) and it's much easier to handle when it's cold. For anybody reading this in the summer, stick your sealant in the fridge before you need it.

Main dealers will charge hundreds to replace all four door carrier seals. Following these steps my Leon is now bone dry, all for under a tenner :)

Footnote: nine years later on and my doors are all still water-tight. Follow this guide and yours will be too :)