S Type Jaguar 3.0 Air leak somewhere in the engine.

Question edited for clarity and translated into written English.
Question moved from Ford to Jaguar category.

You should always take the upgrades. They are fixes to known issues.

All Diesel engines are slow to start as they need pressure and heat which happens after a few revolutions of the engine.

Rough Idle is normally because the Throttle Body and MAF need cleaning.

https://www.google.com/search?q=x+type+2.0+diesel+clean+throttle+body

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check the engine crankcase breather for air leaks little rubber elbow rear of inlet manifold. plus oil separator under fuel rail

you have a possible vacuum leak somewhere or maybe clogged egr

sounds like classic symptoms of air leaking into engine after air meter, check air hoses to engine then when engine at idle - spray detector spray around the inlet manifold and if this is leaking at its gasket (very common problem on V6 at the rear of the engine) the engine note will change. see earlier posts with similar problems. hope this helps - good luck.

As a temporary fix you could try to reatach the pipe together as that will be a breather pipe and the car will not idle correctly as there is now a large air leak

Other than that you will have to buy a new tube

If the car starts again without trouble - it is probably an air leak on the inlet manifold or associated pipework. If the car is very 'lumpy'' then stops it could be a coil-pack or mass airflow assembly - also this fault sometimes triggers a gearbox fault warning as the engine and gearbox become out of sync. due to engine misfires.
The air leak fault will not always register in the fault code memory of the car whilst in its early stages. As the fault becomes greater - the engine will become hesitant - then stop. This is the time to spray leak detector spray around the pipes or manifold joints, as the spray gets 'sucked' into the leak and the engine note will change noticeably.
Hope this helps - good luck.

You probably have a vacuum leak. First: Check the brake vacuum line from the air intake manifold to the brake servo (black plastic pipe running from top of engine to brake servo with flange in the middle). It may be cracked. When engine at idle listen for leaks. You can run your hand along it to try to feel sucking.
Second:
If not that lift the black platic engine cover (3 screws) and look for cracks/leaks in the 1" black house running from front cyclinder bank to air intake manifold. It may be split/sucking air.

You may need to reset the Check engine light. Good luck

yes it sounds like a vacuum leak possibly the line going to the brake booster try to start the car open the hood and listen for a hissing noise you may be able to inpoint where the leak is and fix it with a new piece of hose or a fitting

Do you have access to a good OBD-II reader with live data readout?

The key is to get to the short term fuel trim information.


You has a vacuum leak on the engine.


In order to troubleshoot this, you must start with a clean engine wipe down.


The major offender parts are


air intake gasket on the manifold

air tube after the mass air flow sensor

rubber seal under idle air control IAC motor

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Warm up the engine for 15-20 minutes (LEAVE THE engine at idle) then spray a little Barmen carburetor clear on the potential air leak location (ONE AT A TIME) and listen for a surge in rpm.

If the engine speed go higher that's mean the carburetor cleaner (ADDITIONAL FUEL) got into your engine and that's the gasket you need to change.

There may be multiple leaky spots so take your time and check all rubber gaskets,sensor and hose that are lead into the intake manifold.

When you finish fill up with one tank of Chervon to clean out the injectors.


Try to get a toque wrench and tighten ever bolt on the valve cover back to specification. If you can not get hold of one then just give each bolt a gentle 1/6 turn.



Please post more information after your inspection.

Check breather pipes, common thing on the jags, dragging oil residue and bad air into throttle, look for oil residue on engine.Good luck Davelee