Hello folks,

I am a new Crossfire fan and owner - got my crossfire about 3 months ago. Its a 2004 Limited Coupe with 115k on it. Love the drive and the look of the car, pretty much everything except some minor annoyances of which some are understandable at this mileage (some cabin rattling noises, around dash, side and rear gate windows, also wind noise between door window and roof, and fogging headlight).

Anyways, my major problem is the knocking sounds that can be heard at low engine speeds. The sound decreases as rpm's increase and disappears completely at around 800 rpm. Its very hard to pinpoint where its coming from, maybe a little louder under the car. Also, sometimes after driving, especially aggressively, it would go away even when stopped, at the light for example, where it idles at those low rpms. I just changed the oil, thinking maybe the previous owner put something wrong in there. I used 0W-40 Mobil-1 and Mann fleece filter. One thing I want to note is that the valve covers are leaking some oil - bad gaskets?

If only there was a way to raise the idle speed I will never hear the annoying knocking but with today's electronic throttle bodies I don't know how it can be done unless programming the ECU.

Regards

 

Welcome and sounds like a couple things can be done to get rid of the minor annoyances.

WRT the rattle, at least the hatch rattle. I can be adjusted at the latch and it will cure that nasty noise. There is a thread on here with a couple ways to fix it.

WRT the windows / air noises. Yup, especially in crosswinds. An easy fix is turn up the stereo. Other things that may help are: new weather stripping, window adjustments, treat the old weather strippings to soften them up.

The knocking noise you hear may be something different than what is commonly heard / referred to as knocking at low idle by most folks, but it it is the common noise, it's the fuel injectors. They all do it, some more so than others. I don't usually hear mine unless the hood is open / and or I'm outside the car though. If you here it inside the car, it could be something else. May want to see if fuel injector system cleaning may quiet it down. I have a lot less miles on my 04 than yours too, so it could be something else.

The head gaskets do leak and the simple fix is, replace them. Not expensive or to time consuming if you do them yourself.

Good luck and post us as your ownership continues.

 

The leaking valve covers are most likely the 'vent' covers ( the ones with the hoses connected ).
They come from the factory with MB RTV sealant, there is a thread on here about cleaning them up and installing with new RTV.
WARNING ! Those are aluminum bolts on the vent covers, DO NOT OVERTIGHTEN.
This is a VERY common problem, the rubber valve cover gaskets are usually not a problem, if the bolt torque is correct.

 

Hi, and thank you for the tips.

I forgot to mention that I also used that Chevron Techtron stuff you add to the fuel. I also added a quart of Marvel Mystery Oil during oil change as some have sworn it helped with engine knock.

What is everyone's idle speed? Mine is at that first bigger mark ~ 500rpm.

 

Yes, mostly it is those smaller covers although the valve covers are showing some too. Is it possible that because the covers are leaky the pressure is decreased causing the knocking?

 

No..............

 

If it's more of a knock (heavy) than a peck (light) and adding the Mystery Oil helped, I would start considering oil pressure. Especially if it abates with engine speed.

Can you grab a video of said noise?

 

In case you didn't know, Marvel Mystery oil is transmission fluid mixed with paint thinner.

 

500 RPM for idle is low. Vacuum leak possibly?

 

When were the plugs last changed or cleaned and gapped? Are you using premium fuel? I would do a good going over of things, torque the bolts properly, change oil, plugs, put in new air filters use premium fuel then see if you still have a problem.

 

haha I don't think so. At least I don't know about the transmission fluid part.
"The product is composed of 74 percent mineral oil, 25 percent http://en.wikipedia.org/wiki/White_spirit, and 1 percent lard.http://en.wikipedia.org/wiki/Marvel_Mystery_Oil#cite_note-1 o-Dichlorobenzene (1,2-Dichlorobenzene (ortho-dichlorobenzene))0 - 5% , Fine White Mineral Oil 70 - 100% , Mineral Spirits 20 - 30%" - Wikipedia

 

1. I did not check the plugs yet. Will do that asap.
2. Still would like to know what is everyone else's idle speed is.
3. Let me ask the following: You know how your car starts to roll when you release the brake without depressing the accelerator pedal? Well my crossfire hesitates to roll even down hill! My driveway slopes down towards the street and as I start the car, release the brakes, I almost have to press the accelerator pedal to go down the hill!!! Is this normal? Even driving down the highway as I let go of the accelerator the car reduces speed at what seems to be faster than normal pace. My Chevy Malibu LTZ for example, as accelerator is released, the speed is reduced very gradually, you don't feel it almost (provided you're on a straight horizontal stretch of road of course).

 

My idle RPM's are 1250 at cold start, then 800 after the engine is warmed up.
#3 - that is strange. Jack up each front wheel and see how easy they turn, then jack up both rear wheels by jacking up on the pumpkin ( differential housing ) with the transmission in neutral and check how easy the rears turn.
The fronts should turn really free, the rears will take a bit more force, but once started they should turn smoothly.

 

I think my idle speed is around 600 to 800 RPM. Can't remember.
As far as rolling down the hill; I wonder if your brakes are dragging. However, my XF doesn't roll back too quick when I'm on a hill, the guy behind me is too close, and I have to ease the clutch out. I'm glad of that. Maybe that's just the way these cars are.
Also, I think our cars are geared pretty low, so they might slow down more than other cars.

 

At 500 RPM, it won't move under it's own load. It neads to be 650+

 

See that's interesting. If my idled at 800 I wouldn't hear that knocking. 800 is right about when it goes away.

 

By the way, did I fail to mention that mine is automatic?

Annoyances update:
1. Window wind noise: inserted a rubber tube inside the weather strip that is between the driver window and the roof/windshield area. Also adjusted the window's angle to lean more towards the weatherstrip using the nuts on the bottom of the door. Seemed to help a little.
2. Headlight fogging up: there is actually a bulletin on this. Silliconed the headlight vents, thought it would be the same as putting caps on them. Still fogging up. Maybe there is a crack somewhere.

 

As you probably know, there is no "adjustment screw" for idle speed.
You best check real good for vacuum leaks, particularly the throttle body O ring.
Wouldn't hurt to get a new O ring and remove the TB for a bit of cleaning while you are at it.

 

I'll ask again:

Can you provide a video of the noise? This will go along way toward helping you sort out the issue. There are some very astute members here, but diagnosing without video is like chasing ghosts.

With the idle speed and noise, it could be a stuck EGR. My earlier suggestion of oil pressure is still a remote possibility, hopefully a wrong one.

Also, what weight oil are you running? - Minus the additive.

 

OK, I will get a video soon. I'm using 0W-40 as per spec. I see some people are claiming that dealers are now using 5W40 but I can't find that anywhere locally. The only 5W40 I found is the diesel ones.