OK, my first post :-)

I have this strange issue with my Daimler XJ40 3.6 -89.

On cold start there is this strange sound - like a exhaust leak - a rough sound, almost like a diesel engine. But when driving 5-10 min the sound goes away. If I stop engine (hot) and start right away, the sound is back, again for the first 5-10 minutes, but not as rough - more like a "whining" sound. Appearing when giving a certain amount of throttle - no sound when idle/normal load on engine.

My first culprit was a bad exhaust gasket - leaking from cold, thighten when hot - but the sound is still there after restart hot, i.e. No gasket prob?

Am I wrong in assuming it is a "pressure" issue? Maybe Something to do with the injection? I have no engine error messages or any other electrical issues.

I've searched forums but no similar case. With 600 km away from nearest Jag dealer - can I ask for some troubleshooting advice?

 

Welcome to the forum, of course you can ask for advice.

It might help the guys if you can isolate where the sound is coming from. Left, right, front, rear, top, bottom of the engine.

From you saying it sounds like a diesel, I'm guessing a sort of loud clattering rattle rather than a hiss and woosh.

If it is from the front, top right of the engine I'd stab at timing chain problems, tensioner has a tendency to wear out, but you don't state what miles are on the car.

They can also sound a little noisy until the oil pushes out the tensioner piston.

Some times simply cured by using 20/50 oil and not some mega thin stuff.

Others will have better advice.

 

Another thing that helps is a recording of the sound - most people seem to use YouTube and post a link here.

 

Reading it a few times to take it all in.

I have NOT had the pleasure, but it sounds like an infamous cracked exhaust manifold. That would explain the quietness after some running, AND, the noise returning after a short shut down when hot, the exhaust manifold does cool fairly quickly. The crack opens up as it cools, and closes when the combustion heat gets to work.

The chain tentioner, mmm, maybe, but that noise is more of a rattle/clatter/whirring than a dieseling type of sound.

Too heavy a grade of oil can cause oil pump whine, and oil pump chain whir, BUT, that is in extreme cases.

Our 3.6 runs 10W/30 all year round, and NO issues at all.

 

Just had another thought, damn.

Power steer pump whir/groan. Very common as the power steer fluid is often a forgotten thing until something busts. Thick and gooey when cold/cool, thinner when hotter, and it cools fairly quickly after shutdown.

How old is the power steer fluid????. Now this MAY be that "special mineral fluid", unless the system has been altered, as ours has.

 

Thank you for the feedback, guys. .I can try to isolate the problem better.

I use 10w30 oil, and the car has 176000 km on the clock.

I'll see if i can record the sound and post it here...

 

Hi.

Got to a guy familiar with Jags to investigate, and the problem is a cracked exhaust manifold. I will replace the manifolds (both, while I'm at it and gaskets)

You where on the right track Grant :-) thanks for the feedback.

 

We will consume much alcohol whenever I get to Norway, HAHAHA.

Glad you sorted it.

Might pay to change the fuel filter.

My reason is that there has been some discussions over MANY years that a blocking fuel filter can contribute to excessive heat and cracked exhaust manifolds.

I DO NOT really agree with the discussions, but if I said nothing that would be plain WRONG, and a fuel filter is CHEAP.