My Jag X-type 2.5L V6 engine is not working well, almost dying. Symptoms are: when the engine is started cold, almost

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Customer: Hello Richard,

My Jag X-type 2.5L V6 engine is not working well, almost dying. Symptoms are : when the engine is started cold, almost 100% working fine from idle to 3500 rpm range (I don't push the engine in higher rev when cold). Then I drive and the engine warms up I notice that I have all leak + engine overheat symtom : engine check light above 3000 rpm then above 2500 rpm then always + misfiring and engine very very hot when I open the cover + no more horsepower + no more torque (let's say from 197 HP down to sth like 90 HP....). However, the dashboard is still saying the engine is operating at ideal temperature....

Huge oil consumption then (almost 1L / 100 km...).

Fuel consomption not too bad for the issue used to be 8.9 L/100km before issue, now it is at 9.8 L/100km (on average).

Might have a small oil drops below the car when I park it.

No cooling fluid consumption (it seems that I have more coolant than before the service now..)

mileage is about 100 000 miles (166 300 km).

Year milesima is August 2001.

Thanks a million for your Help !
Answered by Richard in 1 hour 9 years ago
15+ years of experience

19,890 satisfied customers

Specialities include: Automotive Mechanic, Small Engine Repairs, Auto Body Repairs, Diesel Engine Repairs

Hello and welcome to Did the garage or delete scan the vehicle for the stored fault codes? Does the engine idle rough when it is warm?

The website bugs I cannot send you my full answer with lot's of details about the issue. Any idea so I can send you those 20 lines of details?


Hello again,

Attached you can find a .docx file with more details

Thanks for the detailed response. We should make sure you do not have a vacuum leak. Start the engine and listen for a hissing noise while idling when the engine is cold. The PCV hose sometimes will split and the IMT valves sometimes leak. This will cause vacuum leaks. The PCV hose goes from the valve to the intake and the IMT valves are the electronic valves located on the right hand side of the intake manifold. I also see issues with the booster hose from the brake booster to the intake. Also where the booster and purge valve plastic lines go to the intake there are o rings on those fittings which can leak. Lastly the intake manifold gaskets leak when cold causing this.  

Dear Richard,

Thanks for this detailed reply.

Yes, I can hear a hissing noise when the engine is cold and I press the gas pedal a bit. Idling engine is running too roughly to hear sth.

Interesting fact, it happened only once: yesterday, engine very hot going at 5 mph first gear, I hit the brake and nothing, very hard brake pedal just like when the engine is off. Just one time then braking i fine now.

Is that possible you post me links to picture showing what are on my AJ25 engine:

PCV hose
IMT valves
booster hose
brake booster
purge valve plastic lines

o rings

"Lastly the intake manifold gaskets leak when cold causing this." what do you mean by this ?


I will not be in the shop til tomorrow but I can describe these parts. The PCV is a rubber tube under the engine e cover going from the front valve cover where the PCV valve is to the intake just next to the air intake tube. The IMT valves are the two round electronic valves on the side of the intake. They are black and have a two wire electric connector. The booster hose is a plastic hose going from the booster to the intake. The port that the booster hose slides in has an original swam at the bottom. The intake seals are the gaskets that seal in between the engine e intake and top of the Cylinder heads
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19,890 satisfied customers
15+ years of experience
15+ years of experience

19,890 satisfied customers



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