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SEAT Leon 1.8 TSI 25 Edition II common faults.

2005–2009, hatchback, petrol, 160 HP.

The fault list covers: BYJ, BZB, CDAA engine, MQ250, MQ350 transmission.

What you save stays on this device only. My saves

8 fault write-ups. 7 important. 2 recalls.

If you know the year, pick it. Faults for other years drop out of the list.

Before you buy

Known faults

7 important faults

critical2

With the 2008 EA888 VW switched from a belt to a chain, and the tensioner of the first two generations turned out weak: as the ratchet mechanism ages it does not hold its position when the engine stops and the oil pressure disappears. The oil drains overnight and the chain goes slack. The symptom looks harmless for a long time (a short, few second rattle on a cold start as the chain slaps the guide rail), and then one day it jumps, and the engine is badly damaged inside. From then on the repair is a cylinder head or an engine rebuild. Around 2012 the maker was already fitting an improved tensioner; on the old one only replacement helps, not monitoring the noise.

What to check

  • Start it cold. That is the only moment it is audible: a 1 to 3 second metallic rattle
  • Ask whether the chain tensioner was replaced, and ask for the invoice (the part number is the point)
  • If the seller says it only rattles a little when cold, that is not reassuring but the fault itself
2 more steps in the write-up

The wiring harness running under the driver's seat kinks and breaks from the seat being adjusted. The sign is the airbag light staying on on the dash. With the airbag light on the system will not work in a crash, and it fails the roadworthiness test too. The part is cheap, the fault finding is the expensive bit, and many sellers mention it as "just a light".

What to check

  • After switching the ignition on, watch whether the airbag light goes out within a few seconds
  • Slide the seat fully forwards and backwards, and watch whether the light flashes up
  • Look at the wiring harness under the seat: broken insulation, chafe marks
1 more steps in the write-up

expensive5

The light, magnesium cased MQ200 and the MQ250, sized for higher torque, are the most widespread manual gearboxes in the transverse engine VAG models. Both have the same two weak points, and both depend on use.

Show the rest

The first is the differential bearing: as it wears you first get a droning, then a whine from the thrust bearings of the output shaft. Left alone, the planetary shaft can fail and in extreme cases punch through the gearbox casing: from then on it is not a repair but a replacement.

The second is the synchros: they can start crunching at around 50,000 km with aggressive driving. This type does not like dumping the clutch or slipping it, and on a used car that is exactly what you have to listen for.

above 50,000 km

What to check

  • On the test drive with the window down, listen to the gearbox both off and on the throttle: droning or whining is suspect
  • Shift up and down quickly, especially into 2nd and 3rd: crunching means synchro wear
  • Try engaging 1st and reverse when cold: resistance here means wear
2 more steps in the write-up

The door seal ages, and the water runs into the front footwell. It stays in the foam under the carpet, so for a long time only the misting windows and the musty smell show it. The comfort control unit and several connectors run in the footwell: if they corrode, the fault is electrical from then on.

What to check

  • Lift the front carpets and press the foam on both sides
  • Run your finger along the door seals: hard, cracked rubber is porous
  • Smell the cabin when cold
1 more steps in the write-up

The combined housing of the water pump and the thermostat is plastic, and it is bolted directly to the hot engine block. The many heat and cool cycles warp it, it becomes brittle, and then it develops a hairline crack: the fault is almost always the housing, not the pump itself. The signs are slowly disappearing coolant with no visible puddle, the coolant level light, a sweet smell from the engine bay, and later a pink stain under the car. The repair means replacing the pump and the housing together, and the intake manifold has to come off for it: 4 to 6 hours of work. It shows up on model years 2015 to 2025.

What to check

  • Check the level in the expansion tank, and ask whether it needs topping up
  • With a cold engine, smell the engine bay: a sweet smell means a coolant leak
  • Shine a light under the intake manifold, on the right side of the engine: dried or pinkish deposits
2 more steps in the write-up

With direct injection the fuel does not wash the intake valves: the petrol goes into the cylinder, not behind the valve. The oil mist and soot arriving through the EGR and the crankcase ventilation therefore build up on the valve stem and head, and from 80,000 to 100,000 km they restrict the flow. Symptoms are hesitation, loss of power, a rough cold start and misfire. It is not a part failure: it is a consequence of the design, and therefore it comes back. Cleaning (walnut or dry ice blasting) helps for a few tens of thousands of kilometres.

What to check

  • After a cold start watch the idle: rough running and shaking point to coked valves
  • Under load at low revs watch for hesitation
  • With a code reader look for per cylinder misfire (P0300 to P0304)
1 more steps in the write-up

The rear calipers seize: the pad does not release, the disc overheats and turns blue, the car pulls to one side under braking, and the fuel consumption rises unnoticed. On salted winter roads it develops faster. The symptom is easy to mistake for simple pad wear, but a seized caliper takes the disc with it, and often the wheel bearing too.

What to check

  • After the test drive, carefully bring your hand near the rear hubs: a hot side means a seized caliper
  • Look at the surface of the rear discs: a bluish discolouration means overheating
  • Compare the pad thickness on the left and right side
2 more steps in the write-up

cheap repair1

The crankcase breather carries the vapour that forms inside the engine back to the intake, and a rubber membrane regulates the pressure. Oil and heat harden this membrane until it tears, and from then on the intake draws air through the hole in it. The engine control unit does not measure that air, so the mixture goes wrong: the engine shakes at idle, stumbles when accelerating, and the fault memory gets P2279 for an intake system leak. In the other direction oil starts towards the intake, which leaves an oily film in the intercooler and on the intake pipe and speeds up the carbon build-up on the intake valves. The audible sign is a whistling or hissing noise from the engine bay, loudest at idle. The tear is reported between 60,000 and 90,000 km. On the first and second generation the breather is a separately replaceable valve (factory number 06H 103 495 AK) and costs between 80 and 400 euro; from the third generation it is built into the cam cover, so there the cover is replaced. The maker issued three versions up to 2016, and fitting the pressure variant that does not belong to the engine brings the same symptom back.

between 60,000 and 90,000 km80–400 EUR

What to check

  • At idle listen for a whistling or hissing noise from the engine bay
  • Read the fault memory and look for the P2279 code for an intake system leak
  • Take the air filter housing lid off and see whether there is an oily film on the filter and in the housing
2 more steps in the write-up

Checklist

SEAT Leon 1.8 TSI 25 Edition II

First what you would check on any car. Then the faults of this model.

Before you buy

Checklist

The printed sheet starts with what you would check on any car. What you tick stays on this device only.

On every car

Ask the owner

vinkodex.com · Before you buy it, see what can go wrong.

Official recall2 recallsShow

The manufacturer fixes these for free at a franchised dealer. Ask with the VIN whether it was done.

Most recent: 10 July 2017

A12/1053/17Safety recallInjuries10 July 2017 · EU Safety Gate

The earth connection for the control unit for the ABS/ESP system may be interrupted due to a thermo-mechanical overload. If this happens, the ABS/ESP system will fail leading to the risk of an accident.

Remedy: Type of economic operator taking notified measure(s): Manufacturer Category of measure(s): Recall of the product from end users Date of entry into force: 10/07/2017

We could not check this: model year. The authority's notice

A12/01630/24Safety recallInjuriesno date · EU Safety Gate

The propellant in the driver airbag may deteriorate over time. If the airbags deploy, it could result in fragments from the inflator injuring the vehicle's occupants. The product does not comply with the Regulation on the approval and market surveillance of motor vehicles and their trailers, and of systems, components and separate technical units intended for such vehicles.

Remedy: Type of economic operator taking notified measure(s): Manufacturer Category of measure(s): Recall of the product from end users Date of entry into force: Unknown

We could not check this: model year. The authority's notice

Engine and transmission

3 engines · 2 transmissions

BYJ · 1.8 TSI

118 kW (160 HP) · petrol

MQ250 · 5- or 6-speed manual

manual · 5–6 speed

Torque limit250 Nm
MakerVolkswagen

We built the code from the model and the gear count. The factory sheet does not state it. More than one engine code is possible. The fault list shows the faults of each. More than one transmission is possible. 5 gears = MQ250, 6 gears = MQ350.

Variant data

What is in this version

Factory data

Trim
25 Edition II
Body
hatchback
Fuel
petrol
Transmission
manual
Engine size
1798 cc
Power
118 kW (160 HP)
Drive
FWD
Production
2005–2009

Factory service interval

The manufacturer specifies this for this version. Of the mileage and the time, the one that comes first is the one that counts.

  • Air filter

    • 60,000 km or 4 years
  • Cabin (pollen) filter

    • 30,000 km or 2 years
  • Engine oil and oil filter

    • LongLife30,000 km or 2 years(valid only with LongLife-approved oil)
    • 15,000 km or 1 year
  • Brake fluid change

    • first: 3 years, then 2 years(first change at 3 years, then every two years)
  • Coolant (antifreeze) change

    • first: 193,000 km or 10 years, then 97,000 km or 5 years(G13 / G12++: first change at 120,000 miles or 10 years, then every 60,000 miles or 5 years)
  • Spark plugs, petrol

    • 60,000 km or 6 years

Information, not an expert opinion

We write the descriptions, and we put the source next to them. A person reviews them before they go out. They are still information, not a technical expert opinion.

  • A fault on the list does not mean the car you are looking at has it.
  • A fault missing from the list does not mean the model is fault-free. Write-ups are made model by model. Not all of them are done.
  • You decide whether to buy. This is no substitute for an inspection. That needs a workshop and a history check.
Details in the terms