Hi guys, PDX just got hit with an artic cold weather 15 - 28 degree and my car suddenly behaves weirdly....for about a week... the engine was tapping/ clicking much like a diesel engine (valve noise?)...sounds seems coming from the driver side....I can't really hear it from the engine bay. it's only noisy in the morning when the weather is 15-20's but on my way home everything was perfectly fine(30's)....my research points me to VVT chatter? I put Rotella T6 5-40W in my car....should I be worried about this?

 

mine's been doing the same (don't you hate this cold weather?) anyway I chock it up to the speedo cluster.. only does it in gear. There's a valve I think that deals with the evap system (I think..not sure) right behind the drivers side tire in the wheel well.. that also makes some racket but I'm pretty sure my clicking is coming from the speedo cluster.. sounds deep and buried..

From what I understand it's common sadly. :/

 

My XK knocks upon cold start up in frigid temperatures too, though I've only owned it two days. Our XJ does not do it (same 4.2 liter engine). I typically run lower viscosity oil in our cars, which typically helps in colder weather. Since I just bought the XK from southern CA, I'm just assuming they're running higher viscosity oil due to being in a warmer climate. It goes away when it warms up. I've had other cars do it when it gets really cold, but that's the only time it happens. I've never had anything break because of it.

 

Yeap we don't get cold like this..normally 37-38 would be our typical weather....


What oil weight do you use in the winter?

 

Mine made noise when cold (under about 20F) and it turned out to be the pulley bearing on the serpentine belt tensioner was binding when cold.



Dave

 

DaveInVA, did the pulley bearing make a diesel like knock? Did you replace it? I replaced the timing belt in one of our previous cars (6 cylinder), and after about two weeks it began the loudest knock on warm up, but would go away. I had to tear it all back apart and found the hydraulic timing belt tensioner I had bought from an online store had failed. I replaced it with a dealer part and never had a problem after that.

Zidjan, I have ran 0W30 (in one of them 0W20) in vehicles if I change the oil twice a year. I don't really like running these in the summer as I've noticed the opposite problem and the engines can have a slight tick to them when they're hot. If I don't put many miles on it and only change it once a year, I usually run 5W30, but find if it gets really cold it may knock. Obviously every vehicle is different.

 

Sometimes it would make fairly loud knocks when first started and then make a noise like the power steering pump was low on fluid. Then after warm up it would go away. With the belt off you could tell by turning it by hand the bearing was toast. I replaced the plastic pulley with a Dayco metal one with new bearing and also replaced the stationary idler pulley and belt and no more of those noises.


Dave

 

If it is not related to the engine speed, and comes and goes every few minutes (computer engages it on and off every min or so), it could be this:
303-62am Ticking Noise.pdf

My car does this too, and it is much worse in the cold weather.

 

Have someone start the car when it is cold and you just put your hand on the VVT. You will hear and feel that VVT working. Be sure to check both. It could also be your tensioner. If you think it is just watch the belt and if it wonders on the tensioner consider having it checked.

Gus
www.jagrepair.com