Engine knock while idling and turning wheel
 

Hi all,

My X5 started to develop this intermittent knocking specifically when engine is hot, while idling, and with transmission on Drive, and when turning the steering wheel. It will knock for one to three second when I steer left or right under the previously mentioned conditions. When I try to recreate the knock, I sometimes have to do a left-right-left or any combination of steering to get a knock and sometimes it can happen on the first turn. As I said, it's about a second to three seconds of engine knock. I was once able to sustain the knock a bit longer by holding the position of the steering wheel once the knock happened. No knocking when running, accelerating, normal idling (no movement of steering) etc. In fact, the car runs great as I only have 56k miles on the clock, I do have a 'smoking after idling in traffic' issue which seems to be a valve cover gasket issue (based on my research in this forum; specifically McDonalD's thread). I've been searching the forum but can't seem to find a fix.

In addition, no issues when engine is cold, doesn't knock on startup.

Any thoughts?

Thanks,
Philp

1st step: BMW Friendly diagnostics
* run quick diagnostics / test
* you need to scan for stored and active codes

Also, check ps fluid level:
* since you mentioned turning the steering wheel, check the PS steering reservoir. You might be low (see label ATF versus Chf11s)

EDIT MISC:
* might as well check your outer CV boots


Smoke:
* you might be due for an oil separator (aka CCV) replacement or
* any of these combination : valve cover gasket, spark plugs, valve stem gasket+seals, blocked secondary air injection pump
* EDIT added camshaft sensor
* while your doing a major inspection, check the expansion tank for signs of hair line cracks ( pressure test it ) + associated hoses, coolant pipe gasket / valley pan seal / rear block coolant passage cover seal
* I assume you know the rest of cooling system ( what else to check ) and the proper 50/50 mix of the BMW coolant/ anti freeze + bleeding procedure after performing a major or minor coolant system repairs.


EDIT: Life must be really good back there in pinas ;) (v8 X5) ...

How's the petro quality 91-93 octane other than Shell Station ( I always use V-Power Nitro+ petro at 93 when I visit )

Good luck!

Thanks for the response lhordmclain!
I don't get a CEL but will scan for codes.
Overflow tank replaced a year ago.

Pinas is ok, the thirst beast is my one indulgence ;)

Oh and I use the local Petron fuel, XCS with 97 octane and on special occasions, the Blaze 100 octane.

I couldn't tell easily from your description, is the vehicle in motion when this is happening? If the knock is coming from the engine internally, you've got an oil supply problem. Perhaps oil in the crankcase is not being picked up by the oil pump - a filter element may have failed one time and clogged the pick-up screen - or your oil pump is worn out. It's not a situation I would let go without investigation though.

2002 X5 3.0 257,000 miles
2004 325i 114,000 miles

Thanks srmm. No, not in motion. Stopped, at idle, while turning wheel.

Oh, so this is while sitting still - in that case, I would lean towards a power steering pump problem. Since it happens hot, when the fluid viscosity is lower, it sounds like not enough fluid is moving through the pump. So I'd start with a level check. A flush and filter replacement might be in order next. If that doesn't cure it, I think you have an internal pump problem, either wear or relief valve if there is one. (Perhaps one of the more experienced xoutpost members can help there). Good luck.

2002 X5 3.0 257,400 miles
2004 325i 114,000 miles

Since the sound is intermittent and is always associated with moving the steering wheel, I think it is extremely unlikely the sound you are hearing involves the engine. The key to that is that you can extend the sound by holding the steering wheel at the point it starts when the steering wheel has been in motion. Further evidence would be if the knock varies in sound or does not have a consistent cadence. Does the idle drop much when the steering wheel is turned? Are there other circumstances, like the engine is cold or only after you have driven several miles that are particular to when you hear the knock?

I would troubleshoot the power steering components. I would have someone do what you do, holding the brakes with the emergency brake engaged and the back wheels chocked so you can pin down the location of the sound by listening near the power steering pump and the steering rack assembly.

Sometimes bad sway bar links will make noise when they are under pressure from moving the steering wheel, usually closer to the lock point, and the sound can continue for a second or two when you stop turning the steering wheel. However, I would not describe that as a knock but more like something is binding/releasing/binding/releasing. Nor would I expect it to be at all at a consistent rate or matching engine RPM, which an engine knock would do. Suspension parts could be the problem but I would start with troubleshooting the power steering components.

There are many threads about smoke in traffic involving a 4.8. I would search the forum. Sometimes it is just a wee bit and sometimes it is fogging for mosquitos. From those I have read, it is hard to pin down the cause. Sometimes it is at least temporary manageable by going to a different or heaver weight range oil. Valve guide seals are the usual expected culprit but there are other potential less involved cures.