• Hi Guest, welcome to TCG 2.0. Please refer to the FAQ in User Support before you do anything else. It will make the transition MUCH easier.

    IF YOU ARE SEEING AN "OOPS" ERROR PAGE, IT IS LIKELY BECAUSE YOUR BROWSER HAS NOT UPDATED YOUR CACHE. YOU CAN EITHER CLICK FORUMS AT THE TOP LEFT OR VISIT THECHICAGOGARAGE.COM AND BOOKMARK THAT. - Love, Mook

03 Cobra - Rattling noise from front of engine

nytebyte

Not Politically Correct
Joined
Mar 2, 2004
Messages
7,551
Reaction score
51
Just recently my 03 Cobra engine has developed a slight noise seemingly coming from the front of the engine. It’s difficult to describe, but it basically sounds like a brief rattling noise which occurs twice per second at 750 RPM (idle). If I raise the RPM’s, the frequency of the noise changes with the RPM, so if I rev up to 1500 RPM, the noise will occur four times every second. If I rev high enough, it seems to go away.

At first I thought it was the belt since it sounded exactly like the belt making two revolutions per second, but the belt seems fine. The only other thing I can think of is that it has something to do with the timing chain, maybe a bad guide, tensioner or chain.

Also, I seem to get a slight whiff of burnt oil shortly after I start the car when it’s cold. It’s almost undetectable, but I’ve noticed it now twice. I checked for oil leaks and found none. Not sure if it’s related, but it started at the same time the noise started. Are the timing chain tensioners on this engine hydraulic, filled with oil and maybe leaking?

The car runs perfectly fine and performs normally otherwise. Not sure if this is a clue, but I don’t drive the car much, so it sits in the garage for sometimes two weeks or more at a time. In winter it sits even more and is only taken out on nice days.

Anybody have any ideas? Are there any known issues with 03, 04 Cobra timing chains or related hardware? Not sure where to even start here.
 

VenomousDSG

Smells own farts
Joined
Apr 30, 2006
Messages
13,387
Reaction score
54
Location
Yorkville, il
Could be a pulley issue, which these cars are notorious for having problems with the stock ones. You don't have the billetflow upgraded pulleys do you? Even if the belt looks fine too it could still be that, as it expands over time and it will not create enough tension on those picky pulleys.

Just out of curiosity, how many miles are on the car, and have you ever changed the supercharger oil? If you haven't and it has some decent miles on it, that could be the issue. it could be all drying up and thick like molasses and not lubricating the inside of the supercharger.
 

nytebyte

Not Politically Correct
Joined
Mar 2, 2004
Messages
7,551
Reaction score
51
I have billetflow pulleys all around and changed the supercharger oil about 10K miles ago. The car has 45K miles.

I don't think it's a pulley since the noise wouldn't be as methodically repetitive as it is. Tension on the belt is good.
 

VenomousDSG

Smells own farts
Joined
Apr 30, 2006
Messages
13,387
Reaction score
54
Location
Yorkville, il
hmmmm, try uploading a cellphone video later when you get a chance. Would probably help a lot in determining what it is if people can hear it.
 

IZZy

Powered by ES
Joined
Dec 15, 2007
Messages
38,986
Reaction score
2
Broken rocker arm? I think this was also common on our cars
 

Flyn

Go ahead. I'll catch up.
Super Moderator
Joined
Mar 1, 2004
Messages
46,491
Reaction score
59
Location
Selling homes on the Gulf Coast of Florida
I had a couple spark plugs work loose in my Cobra. Check them before the threads are destroyed or you will need to add inserts. Thanks to John (forget his screen name but he was popular and prolific on CSVT) for helping me with the inserts. He's a good guy.
 

nytebyte

Not Politically Correct
Joined
Mar 2, 2004
Messages
7,551
Reaction score
51
Ok, here is a short video of the noise where you can clearly hear the knocking. Also, I don't know why there seems to be a loud whirring noise in this video. The whirring noise isn't nearly that loud when you're standing in front of the car. I think it's an anomaly of the phone camera mic.

Also, I checked all the plugs and they're snug.

https://sabercathost.com/4X9z/Engine_Noise.mkv
 

Marko

Well-known member
Joined
Feb 19, 2005
Messages
16,546
Reaction score
38
Take your car to someone like Hans at Deans Performance. He's an expert with the 03/04 Cobra
 

nytebyte

Not Politically Correct
Joined
Mar 2, 2004
Messages
7,551
Reaction score
51
Deans is pretty far from me. Know of any good shops near the north suburbs?
Wasn't there a decent place near the Schamburg / Palatine area at one time? Are they still there?
 

nytebyte

Not Politically Correct
Joined
Mar 2, 2004
Messages
7,551
Reaction score
51
Yes, Speed Inc. is what I was thinking of, but I checked and they only do GM stuff now.

DMP looks good and is a LOT closer. Thanks for the info Venomous.
I'll give Drew a call tomorrow.

This whole situation is making me sick. I love the car and have always gone out of my way to take very good care of it. This is the first "real" problem I've had with the car in 14 years.

Not sure what could have happened. I drive like a granny and the engine rarely ever sees anything over 3000 RPM.
 

VenomousDSG

Smells own farts
Joined
Apr 30, 2006
Messages
13,387
Reaction score
54
Location
Yorkville, il
It could be a multitude of simple things. If it's still running fine, i wouldn't get too worked up about it. Drew will check it out and take good care of you.
 

nytebyte

Not Politically Correct
Joined
Mar 2, 2004
Messages
7,551
Reaction score
51
Update: It was the water pump.

I wouldn't think a water pump would make that kind of noise, especially at those intervals, so I didn't check it at first, especially since it's no fun to get to.

New water pump and noise gone. I guess I got all worried for nothing.

I still gotta bring the car to Drew at Dmarkperformance for the transmission issue. I can't seem to figure that one out.
 

BADAZZTEALCOBRA

Well-known member
Donating Member
Joined
Apr 13, 2008
Messages
20,966
Reaction score
199
Location
Streamwood
Update: It was the water pump.

I wouldn't think a water pump would make that kind of noise, especially at those intervals, so I didn't check it at first, especially since it's no fun to get to.

New water pump and noise gone. I guess I got all worried for nothing.

I still gotta bring the car to Drew at Dmarkperformance for the transmission issue. I can't seem to figure that one out.
See how my car is coming along when you're there. :bigthumb:
 

Create an account or login to comment

You must be a member in order to leave a comment

Create account

Create an account on our community. It's easy!

Log in

Already have an account? Log in here.

Top Bottom