[LankyJ]

I have just picked up my 300C on Saturday, 10/30 and have since put on about 450 miles. On Thursday I started noticing the following problems/noises that are NEW, I don't know if they are all conected but I beleive them all to be linked to the exhaust. Please let me know if anyone else has experienced any of them and what i should do:

1. In park, when I rev the motor th exhaust note has not only become considerably louder (more baffled) but has also developed a tinny / raspy after tone once the revs start going down that's sounds like it's coming from the mufflers not out of the tips.

2. Under exceleration, moderate or hard, the trans seems to kick down too early. It's either that I'm not getting all of the power from a gear that I've become used to over the past several days or that for some reason my exhaust has gotten louder and is amplifying the revs. However, it truley does feel as if I have lost power somewhere. When passing on the highway, I'll excelerate and it will kick down and rev high before I get all of the power band out of the gear.

3. At slower speed, either braking or accelerating (at stop lights...etc.) there is a "feeling" that's coming from the pedals (gas and brake) This feeling is super hard to discribe. Again, this may very well be an exhaust vibration that has just started. It's a feeling of "less than the liquid smooth feeling that I used to feel" almost like a slight grinding, very very slight.

I truley have no idea what the problem is but I know it is a problem that I don't like and would like to have fixed. Please help....

 

[LankyJ]

Just picked up gas at lunch today, also noticed that my Avg. MPG has gone from a usual 16.5 - 17 to a 15.1 (does not move) hasn't changed from this morning, about an hour of driving.

(also check the entire posting regarding my issues, found none)

Do any C owners notice a quiet "belt"" noise when car is on and in park from outside of the car?

 

[rogue]

First of all, it sounds like you are adapting to your new car. The transmission is adapting to your driving style. Pick a driving style and stick with it. If you plan on driving the car hard, start now and your trans will learn what you like. My trans often revs as high as 4k RPM in first gear under low throttle. This is because I drive aggressively these days. When I take it easy on the throttle, the car shifts differently. The tranmission is adaptive.

I believe the noises you are hearing is the V8 rumbling during idle. My car makes a "belt" noise that could easily be confused with a slight pinging from time to time. This is a V8, a quiet one, but not as quiet as a Lexus.

The vibrations you are feeling through the pedals is most likely the exact same thing. You have a hemi under the hood, the vibrations are normal and so is the gas mileage.

Reset your MPG meter on your EVIC when you are on the highway and see what it reads. It will most likely read 20mpg+ which is normal. To me it seems like you are just getting used to the 300c. I experienced nearly all of the above the first few days with mine.

 

[steves300c]

The other day I reset my mpg indicator going down a hill at 60 mph.
My avg mpg was 1042 mpg! That QUICKLY changed when I started going up a hill about 10 seconds later. LOL
I usually avg about 15-16 mpg with a very heavy foot. I don't know what your driving style is like, but it may be similar. Also, if you are going up more hills/inclines as opposed to the terrain you drove on before, it will drop.
The ticking sound from your engine compartment is probably fuel inj tick.
Mine was pretty noisy the first 500 or so miles. But now with 2300 miles, it's as quiet as a mouse at idle. Absolutely no ticking.
The tinning/raspy sound may or may not be due to carbon buildup on the exhaust pipes. I haven't crawled under mine lately to check for heat shields, but you might have a heat shield slightly rattling against the exhaust pipe.
If your trans is kicking down fast on moderate to hard acceleration, that is not a problem. It should do that. Mine kicks down on light accelerator pressure. I want it to be responsive, and am glad mine does this. In order to get more power as pedal pressure is applied, the transmission will step down to a lower gear depending where in the power band your currently held gear is. Think about a manual trans for a minute. If you are cruising along at 60 mph in 4th gear, and then suddenly need to pass someone that pulled right out in front of you(usually a snowball LOL), you would drop it in to 2nd and punch it to pass the traffic offender as fast as possible(Lord knows, I don't want to be stuck behind that idiot). Your auto trans will do the same thing, you just don't have to press the clutch, pop it into 2nd, and nail it, with an auto, just nail it.
I'm not sure of the feeling you are getting from the accelerator or brake pedal at slower/lower speeds as I haven't experienced this.

 

[LankyJ]

I'm sure you are right and I do appreciate the feedback. I am aware of the power under that hood. I'm just comparing what I'm feeling / hearing now (today and yesterday) compared to the first 5 days. It became less liquid smooth and the exhaust has definitely gotten more throaty/tinny. I can hear it (with out trying) now even under the slightest accelerations. The first 5 days I heard / felt nothing like this, super smooth.

I know cars break in but this much only after 5 days and 450 miles?

 

[LankyJ]

steves300c >>>
I get what you are saying and I agree. The point at which it chooses to down shift has changed. I would have much more power in the current gear prior to it downshifting then it does now. And if it did downshift, the power I would feel was much more substantial than what I'm feeling now when it
downshifts.

There was more power on tap before in each gear prior to the down shifts / upshifts... now for little acceleration it downshifts and seams to scream with less power / acceleration (I don't feel it in my ass like I did and it's screaming).

It's either this or all of these things were happening but I wasn't hearing them, which again brings me back to the exhaust. I know it might sound like I'm tripping out but I'm not.......should I bring it to the dealer?

 

[steves300c]

steves300c >>>
I get what you are saying and I agree. The point at which it chooses to down shift has changed. I would have much more power in the current gear prior to it downshifting then it does now. And if it did downshift, the power I would feel was much more substantial than what I'm feeling now when it
downshifts.

There was more power on tap before in each gear prior to the down shifts / upshifts... now for little acceleration it downshifts and seams to scream with less power / acceleration (I don't feel it in my ass like I did and it's screaming).

It's either this or all of these things were happening but I wasn't hearing them, which again brings me back to the exhaust. I know it might sound like I'm tripping out but I'm not.......should I bring it to the dealer?

I think I see what you are talking about. Are you saying that even though it downshifts and rpms are climbing fast, it doesn't feel as fast as before?
One of a couple things here, 1 is you have gotten used to it. 2 is, are you using the recommended 89 octane and not 87 or 93? I've read that using 93 can actually be a hinderance to this motor? I don't know how true that is, but...
I know I get used to the performance of this car, then will end up driving my wife's Olds Silhouette for the weekend, then get back in the C on Monday morning and it's like, whooooosh! Ah, passing power again!
I've had my mufflers removed, so mine is a bit louder than stock anyway, not annoyingly loud, just a touch more rumble, but when I had the mufflers on it, I only remember hearing the exhaust on WOT. Carbon buildup in the exhaust and mufflers will create a deeper tone to the exhaust, but I don't know if that will happen within 500 miles.
If it does bother you, by all means, you should take it to the dealer and at least have them check it out. I had become very 'service dept unfriendly' after hearing 'could not duplicate customer concern' too many times on previous cars, but broke down and took my C in for a few things(fully expecting to hear ' could not duplicate'), but was pleasantly surprised when they acknowledged the concerns, and actually fixed them!
Good luck!

 

[LankyJ]

I appreciate that and yes, that's exactly what I'm saying. I've been using the 89 octane. I too have become that way with service centers and am hesitant to start with this one. I'm going to bring it in this weekend and see if they can help. Again, I appreciate your reply.

 

[KC300C]

If it does bother you, by all means, you should take it to the dealer and at least have them check it out. I had become very 'service dept unfriendly' after hearing 'could not duplicate customer concern' too many times on previous cars, but broke down and took my C in for a few things(fully expecting to hear ' could not duplicate'), but was pleasantly surprised when they acknowledged the concerns, and actually fixed them!
Good luck!

I agree with Steve, for his reason stated above, but also to document any of these small problems in case they turn into big problems, especially when you start getting close to the end of the warranty. I found this out on my '02 Suburban this passed Summer. I noticed a slight burning smell and a hum coming from the rear end with about 2,000 miles left on my warranty. I took it in twice, but they could not figure it out. This summer while pulling our camper through the Colorado Rockies, the rear end devoured itself. I was 7,000 miles over my warranty and it was going to cost me 4 large to fix it. I don't think so!!!! I called GM customer service and since it was documented prior to my warranty expiring, GM paid for it.

Have the dealer document everything and keep a somewhat detailed record of your visits to the dealer for repairs including keeping all of the receipts. If they could not find the problem when you bring the car in, make sure they note that on your receipt.

Good luck with your 300C. I called Union Pacific today and my cool vanilla "C" is being unloaded onto the carrier and should be at my dealer tomorrow. Unfortunatley I will not be in town to pick it up until the weekend. Oh well, I've waited 13 weeks already, what's an extra few days going to hurt.