My 07 XK X150 4.2 NA has a very pronounced squeal just after starting the engine. It goes away after 30-60 seconds. Alternator is new and all the pulleys, tensioners, water pump, drive belt, auxiliary coolant pump have been recently replaced. I've run out off ideas what is causing the noise. I'm hoping y'all might have an idea.

Details:
Noise occurs when engine is cold. It starts ~5 seconds after the engine starts. It goes away after ~60 seconds.
Higher RPMs don't change the sound.
Noise sounds like it's on the right hand side near the radiator/alternator.
Car is RHD.
If you turn the engine off before the squeal goes away, the noise continues for a second or two, sounding like something spinning down.
Pulling relay #3 under dash before starting engine has no noise. When car is running and plug in relay #3, noise occurs as above. So I assume the problem is on that circuit.
Air condition system was empty of gas.

What's been tried:
Belt dressing
Replacing tension, idler pully, water pump, hoses, auxillary coolant pump(attached to radiator).
Alternator was replaced almost 1 year ago. Noise was there before alternator was replaced.

Thanks much for any help or ideas of what to look at.

A

 

Belt dressings are never the fix. To pinpoint an issue, a stethoscope is your friend.
But without being there, I'd bet $1 that its a belt tensioner, the generator spindle, or something similar.

 

I use a flexible tube as a stethoscope. My go-to is a vacuum cleaner tube. Works everytime, just move it around and listen.
Rick

 

And belt was not installed inside out?

 

on my 1994 xjs, had this and had to replace the hydraulic damper. "2007-2009 Jaguar XK Vibration Damper AJ811116"

 

From your description that sounds like the secondary air injection pump.

 

I agree!
WJ

 

Funny you should say that. The one detail I forgot to add was on my way home, I got a fault for the Secondary Air Injection Pump. I'd never seen that before hand.

How deep in the engine bay is it located? The radiator, fans, etc are out right now.

And is there only one? There was mention of one of the banks was running lean. is there one for each bank?

Greatly appreciate your insight.

 

Did you look at the Workshop manual?

Where do I send the $1?

 

remove right side front wheel well liner and you'll have acess or remove r headlight, same scenario.
wj

 

Brilliant!!

 

When changing the pump, I assume the valve needs replacing. Is it hard to get to? I've checked the manual, but it doesn't give a good explanation where everything is. Thanks much

 

I'm assuming the squeal is actually the blower motor within the airpump. It is a squirrel cage type. I replaced mine, don't quite remember the exact procedure but it was straight forward. Unbolt several rubber feet mounts, unplug electrical, remove the pump's exhaust tube...reverse procedure.
wj

 

Redoubled my search and found the instructions in the manual. Looks like the valve is over by the water pump under the air intake. Manual says you don't have to take the hood and radiator support out, but we'll have to see. Major warning not to damage the pipe to the exhaust 800 Euros if you can find one. Ouch.

 

but the noise is the pump, not 'valve'. Different location.

wj

 

Yes, the noise is the pump, definitely. But reading somewhere it said new pump won't last long if valve is bad. Shop said they heard a vacuum/air leak. I'm wonder if it might be the valve. When I pick up the car, they'll tell me where they hear the leak.

It's hard to find a replacement. Would you know if part number is cross referenced with another, possibly Ford, part? Would be nice to save a few bucks.

 

I think noma autp parts on ebay has some, they are reliable.


wj

 

I have my car back and had a good conversation with my mechanic.

I'm not getting any check engine codes and so far the only problem is the noise on start up and that's for only 30 seconds.

Question: Is there any harm in just driving the car? Pump is definitely bad and will need to be replaced (alone with valve). My only immediate concern is passing NCT inspection in a few weeks. As long as there are no codes showing, I should pass.

I've kinda blown my budget this year on a new radiator and a few others new bits. Saving a few bucks has its appeal right now.

Cheers

 

Why not spend a little time, remove headlight 15min, remove front shroud on air pump, 30 seconds. spray a bit of wd40 onto the motor shaft. Reverse steps and see if that helped? Less than an hour's time. Might save you for a few years.
To answer the question, not a problem as long as it continues to spin, noisy or quiet.

WJ

 

That I will do. I might be able to get to the back of motor from engine bay, or do I need to spray from the other end?

Really appreciate your wisdom.