Hi Boys and Girls, I have a 2003 XK8 where I have about 150 miles left on an extended warranty with an elusive noise.


It starts at around 70 mph with a "ticking" every now and then, getting louder and more frequent to around 85 to 90 (haven't pushed it beyond) and seems to get worse when going steady state speed or decelerating.


I had the dealer do the de-carbonizing for the head twice, replaced thermostat, replaced pugs. To fix a ping and engine going in to protected mode, the air mass sensor was also replaced.


It seems to be a little more prevalent if holding the car in 4th gear at the 70-75 mph range than if in the automatic mode. normal or sport mode in transmission does not seem to have an effect.


I checked for loose bolts, fasteners, etc., under car and had dealer do the same. Banged on exhaust components and eliminated the usual suspects.


I have a tried a mix of 50/50 and 60/40 ratio of 91 octane and 100 octane racing fuel (60/40 right now).


I checked for crap under the seat (loose change, rawhide chew toys, old cigarette boxes from previous owner, etc. were removed.


I have a brother that was a Lincoln dealer parts and service manager who suggested there were cars of this vintage in the Lincoln line where the AC condensate drain was positioned where condensate would hit the catalytic converter and cause a similar "cracking" noise.


It is a little difficult to get the fix established as the only places where speed limit that the problem occurs is in that range is a ways out of town or justified by keeping up with other traffic that happens on the desert area highways.


Questions:


1) has anyone had similar problem with solution?
2) to look in to the AC condensate issue, does anyone know the exit location?


Lot's of Thanks and Kind Regards to those who contribute to the forum.

 

I have a terrible track record at guessing noises but can tell you about the condensate drains.

There is a drain on either side of the plenum chamber (item 5 - location of LH arrowed in red).


(click on the image to enlarge it)


Tubes from these lead down either side of the transmission and drain directly onto the ground beneath the vehicle.

They can often get blocked with mud etc but can be cleared with a fine wire. If they become detached from the outlets, the front carpets get soaked with condensate.

Graham

 

Thanks Graham!
I will put it up on the ramps tomorrow and check to see if they are clear at the same time. At least I know where to start the hunt.


Kind Regards,
Steven