Skip to content
KickTyres
MajorVery commonCooling

Jaguar X-Type: Plastic cooling system failures — thermostat housing, radiator end tanks, expansion tank (V6)

Plastic cooling system failures — thermostat housing, radiator end tanks, expansion tank (V6) is a very common cooling fault on the Jaguar X-Type on the 2001–2009 cars, and we rate it major. Putting it right costs $300 to $1,200 at New Zealand independent workshop rates. Below is what goes wrong, the symptoms to notice on a test drive, where to look, and what to ask the seller before you hand over any money. It is one of 9 documented faults on the Jaguar X-Type.

Vehicle
Jaguar X-Type
Years
2001–2009
Fuel
petrol
System
Cooling

This page covers the Jaguar X-Type as a model. Some faults only affect particular engines or build years — enter a plate below to narrow the list to one car.

All Jaguar X-Type faults9 documented faults on this model

What you are looking at

An annotated photograph of an automotive engine thermostat identifying the wax capsule and both disc valves.Example of the part — not this vehicle

A double-valve engine thermostat, labelled: the wax capsule is what sticks.

Dougsim · CC BY-SA 3.0 · Wikimedia Commons

What goes wrong

The X-Type V6's cooling system is full of plastic parts that go brittle and crack with age: the plastic thermostat housing integrated into the upper hose is a famous leaker, the radiator's plastic end tanks split, and the expansion tank cracks around its hose nipples. Any of these can dump coolant quickly, and an overlooked leak will overheat and warp the alloy V6's heads. Parts are cheap and the fix is straightforward, but on any X-Type you should assume the plastic cooling parts are on borrowed time if they have not already been replaced.

What you would notice

  • Coolant smell or visible pink/green residue around the thermostat housing
  • Coolant level dropping between checks
  • Crusty deposits on the radiator end tanks or expansion tank
  • Temperature gauge creeping up in traffic

How to check it

Where to look. Thermostat housing at the engine end of the upper radiator hose; radiator end tanks and expansion tank at the front of the engine bay

With the engine cold, check the expansion tank for hairline cracks and staining, squeeze the upper radiator hose near the thermostat housing and look for dried coolant around it, and inspect the radiator's plastic side tanks for white/green crust. Ask which cooling components have already been replaced.

Parts involved: Thermostat, Coolant expansion tank, Radiator.

What it costs to put right

$300 to $1,200 at New Zealand independent workshop rates. That is for this job on its own, not for the car.

An estimate, in NZD, for the repair as normally carried out. What a specific car costs depends on which part has failed and what it damaged on the way — treat this as the floor for a negotiation, not a quote.

Ask the seller

  • “Has the thermostat housing ever been replaced?”
  • “Has the car ever overheated?”
  • “How often does it need coolant top-ups?”

Now check the Jaguar X-Type you are actually looking at

Everything above is true of the model, and it is free. What it does not tell you is whether THIS car has been looked after: its odometer history and whether the reading has ever gone backwards, whether there is still money owing on it, whether it has been reported stolen, how many owners it has had and what it is really worth today. That comes from the official records for that plate. Enter the plate for the free details, or get the full history and a market valuation from $13.49.

Not sure what you would be paying for? See what a full KickTyres check includes.

Where this comes from

The failure described above is documented in the sources below. The inspection instructions and the cost estimate are KickTyres’ own interpretation of them.

  • jaguarforum.com 'The dreaded Thermostat housing!' thread
  • RepairPal Jaguar X-Type coolant leak symptoms page
  • Go-Parts 2002-2008 X-Type radiator guide

Jaguar X-Type buyer questions

Is plastic cooling system failures — thermostat housing, radiator end tanks, expansion tank (v6) serious on a Jaguar X-Type?

We rate it major and very common on the Jaguar X-Type. The X-Type V6's cooling system is full of plastic parts that go brittle and crack with age: the plastic thermostat housing integrated into the upper hose is a famous leaker, the radiator's plastic end tanks split, and the expansion tank cracks around its hose nipples. Any of these can dump coolant quickly, and an overlooked leak will overheat and warp the alloy V6's heads. Parts are cheap and the fix is straightforward, but on any X-Type you should assume the plastic cooling parts are on borrowed time if they have not already been replaced.

How much does it cost to fix on a Jaguar X-Type?

$300 to $1,200 at New Zealand independent workshop rates. That figure is for this job on its own. A car showing the symptoms on this page is usually worth either walking away from or negotiating down by at least the repair figure.

Which Jaguar X-Type years are affected?

Our research records this fault on the 2001–2009 Jaguar X-Type. Build dates move around, especially on imported cars, so treat the range as the years to look hardest at rather than a guarantee either way. The official records tell you the exact build and first registration date for the car in front of you.

How do I check for it before I buy?

With the engine cold, check the expansion tank for hairline cracks and staining, squeeze the upper radiator hose near the thermostat housing and look for dried coolant around it, and inspect the radiator's plastic side tanks for white/green crust. Ask which cooling components have already been replaced. Look here: Thermostat housing at the engine end of the upper radiator hose; radiator end tanks and expansion tank at the front of the engine bay