On 10/3/22 I bought a CPO Pre-Owned GLC63 AMG with 12K miles.
It is still under the Factory Warranty until 12/2023, then the CPO kicks in until 12/2024.
On 10/15th I was ordering New All-season radials for it and when I checked the passenger front wheel I noticed that two of the lug nuts were stripped and only in there hand tight.
One other lug on that wheel was so swollen I could not get it off. There were one or two other swollen lugs on other wheels I could not get off.
It took my local garage almost an hour to get that wheel off, making me question if the car actually went through the stringent CPO process, there is no way they could have inspected that wheel's brakes, rotors, etc...
The dealership actually reimbursed me for the 20 one piece lugs I had to order to install my new tires on 10/19th.

Now to the engine/performance....
On 10/27th my Engine light (cel) came on.
I called the dealer and the service advisor told me as long as the light is not flashing it is safe to drive and give it a few drive cycles to see if the light goes off.
On 10/29 the cel was still on and my local garage scanned the codes and got:
P152B00 - Current - leakage in inlet air system - cylinder bank 1
P227900 - Current - leakage in inlet air system
P002177 - Stored - inlet camshaft (cylinder bank 2) differs from specified value, camshaft position cannot be achieved
P012800 - Stored - engine coolant temperature is below the coolant set temperature.

I called the dealer again, they said safe to drive and they set appt for 11/18th.
The CEL went off a few days later.

On 11/12 I hooked up my dragy and did a couple of 0-60s:
4.23 and 4.15 - definitely a little bit slower than expected.
On 11/14 the cel came back on.
11/18th took the car to dealer and they got code p012800
11/22 - they updated software and cel went off.
11/23 - picked car up and on way home from dealer CEL came back on.​​ I hooked up dragy to try a 0-60 with cel on and got a 4.89, definitely down 80-90 hp. Called dealer and set appt for 12/12.
12/1 - cel went off
12/2 - tried a 0-60 and got a 4.50 (4.24 with rollout), definitely down 45-50hp.

Looking back at my carfax on 6/22/2021 - went to dealer and "body electrical system checked"

Keep in mind, I am not using the Original Dealer for service, they are too far away, I am using my local dealership. For my next service appt there I am using a service manager my son knows personally.

Any advice, experience or opinions as to what is wrong with this car would be appreciated.
I am wondering if the car had been tuned originally or modified and not restored back to stock correctly.

I have no problems with a tuned car, but they would not be able to CPO that car.

 

While it's certainly possible you've just hit a run of terrible luck, this isn't the first time an MB CPO'd car suddenly turns out to have issues that should have been caught by the CPO process. I had a 2009 E550 that I bought CPO. Turned out the car had very poor paintwork on the roof and the headliner was clearly askew in the rear. The electric sunshade for the rear didn't work either, when I bought it they just said take it to your local dealer (I bought the car a couple of hundred of miles away) to get fixed, should be no big deal. Months later, lo and behold something popped on Carfax, my body shop surmised that the original owner drove under a parking gate which dented the roof.

I would definitely encourage you to open up a case with MB corporate. That was the only way that I was able to get the selling dealer to buck up for all the paintwork that needed to be done in addition to the other stuff. Have you contacted the selling dealer? You should also ask your local dealer for any information on previous service history, it's one of my checkboxes whenever I've bought any used car, CPO or not, along with whatever repair order was performed in order to bring it up to CPO standards. Since the car is under warranty, I would expect that any service was performed by a dealer so they should have access to that information. Depending on your trust of your local dealer, maybe ask them to perform a comprehensive PPI or reinspect the car as-if they were getting ready to sell it CPO.

 

Thanks so much for the advice and previous experience:

I bought mine about 60 miles away in another state, so the local dealership is much more convenient for service. On carfax they are the original dealer who sold the car and had performed some services after that.
Plus I know the girl who sets up the appointments, she lives around the corner and my son is friends with the new Sales Manager there. He had the Sales Manager have a much more proactive service advisor take over the service on the car.
That service manager called me and took down all the info, where the previous guy said he didn't need those codes, they could see them when they scanned the car.
I told the new service manager about researching that same code being related to a stuck thermostat and he said that they are going to replace the thermostat to rule it out.
At that point I know they will hold the car for a coupe of days to make sure the CEL does not come back on, probably have the tech or service manager drive it to and from work.
The p012800 CEL is often due to the car not reaching operating temp fast enough due to the thermostat being stuck open.

I have not contacted the original dealer about the engine issues yet. I have no faith in them and I do not want them getting their hands on the car. When all this is figured out, I will contact them.
I do plan on contacting Mercedes Corporate to report my issues with the original dealer depending on the outcome.

One thing that concerns me is the performance of the car.
If the CEL is off after the thermostat and the performance stays in the 4.5 (4.25) with rollout range, that would indicate a 45hp deficit.
If it runs consistent 4.1 (3.9 rollout) that would be close to the posted 3.8 with rollout in all the magazines and would be within a normal range, but anything over that is way off.

I don't think Mercedes will due a comprehensive engine test, leakdown, etc..., but if the car is not running correctly I may put it on a dyno and see what is going on in terms of power.
The more info I have for corporate the better.

I truly hope this is some form of electrical problem that can be corrected and not a mechanical engine problem.
Both are bad, electrical gremlins are tough to correct and getting Mercedes to replace a $50K engine is not going to be easy.

My stock 2018 Trackhawk had numerous electrical issues causing the engine to go in to limp mode, due to the engine feeling it was sucking in too much air.
I was about to have it lemon lawed, but I traded it for $5K less than I bought it for and was happy with that.
The similar Mercedes codes about leakage in air inlet concern me. I will make sure the dealer checks for pinholes and/or loose clamps.

I have not modified this car, I am very strict with my CPO cars so as not to void the warranty.
My 911 Turbo S had a CPO warranty that expired in 10./2022 after 2 years. The only mod I did was a catback which had no issue on that warranty and that CPO saved me $4K in brakes and a $7K Turbo that failed and was replaced.
Now that car has a larger catback,100 cel cats, and a high flow air filter. I have a JB4 tune waiting to be installed.
I realize the value of CPO.
The heavy Turbo S cabriolet ran a 0-60 in 2.91 (2.73 with rollout) bone stock on the dragy, right in line with posted figures. Definitely not the fastest, but normal.

My possible concern is that somebody may have modded the GLC63 and the CPO dealer did not check for it and that tune will be blamed on me, but that is getting ahead of myself.

I will say, the performance of this GLC63 even when it ran the 4.1 and 4.2 was underwhelming, it has no snap off the line as most owners state it does.
It sort of bogs and then goes, the Trackhawk would rip you back.

My Porsche will make you dizzy it is so violent.

Considering posted for the Trackhawk is 3.5 and the GLC63 is 3.8, they should be similar.

Thanks again for the advice!

 

Investigation of any intake-related issues on this engine should include verification that the vapor separators (catch cans) are functioning properly. These are a weak link on this engine and can lead to rear main crankshaft oil seal failure because of crankcase overpressure. Not clear if the vapor failure is always, or usually, preceded by intake CEL codes. It's something to consider.

 

Thanks!
I will have them look into this.

 

Wednesday 12/7th the CEL is back on.
Car has 14,209 miles.
Dealer picking car up 12/13th.

 

Thanks for the update. Please let us know what the diagnosis is when available.

 

I will, if my experience can help somebody else in the future that is a good thing.

 

Today 12/15/2022 the Service Department reached out to me.
Mercedes had a bulleting about this problem and said to check the Thermostat Operation which was found to be OK.
If the Thermostat was OK the bulletin said to Bleed the coolant system which they did.
They said this will solve the problem.

I am skeptical.
I asked the Service Manager if this would have caused the car to be so slow with the CEL on and he said possibly.

If I get this car back and it is still running 0-60s in the 4.5 range I will need to consider if this car has some form of engine damage or if there is another underlying problem.
I truly believe there is some sort of leak in the air intake system, but I will get the car back tomorrow and hopefully all is OK..

 

Thanks for the update. Please post a copy of the service invoice with your personal information redacted. It will be interesting to see exactly what they did.

 

will do

 

If you really think you have an intake leak, find a smoke machine, they make them for this use actually. Start the car and then shoot some smoke around the intake area. If you have a leak, you'll see the smoke get sucked in. You will have to move the cover and expose the edges of the intake so the smoke can get near the mating surfaces. I am not recommending the following, just so you can see what I am talking about.

 

Thanks, just got car back, if CEL comes on again or if car is running like a snail I will check that out.

 

Here is the 2 services done for the CEL

I redacted personal information as advised by my lawyer "chassis" LOL

 

Thanks.

Summary of service work: Mercedes knows there is a problem and they don’t have a solution.

And the coolant was drained and refilled.

 

Drove to work with it today, 12 miles from home at 14297 miles the CEL came back on.
Dealer is picking the car up again tonight when they drop my wife's car back off.

I called the dealership I bought it from.
They said the car was checked out according to CPO and they stood by it.
They offered to take the car to their shop 100 miles away and check it out if my local dealership cannot get it right.

I am really frustrated, I know it is a first world problem, but it still is annoying,
I paid good money for the car and it is in the shop more than I have it.

The original dealership says they will make things right, but they also said they understand if I call corporate.

 

Update:

My local dealer decided not to pick up the car.
They said they can't fix it and sent me a Service Bulletin from Mercedes which I will attach claiming the car is safe to drive and there are no performance issues.
However, they did not replace the Thermostat, they only bled the coolant system.
Also, the performance of the vehicle according to my dragy shows it is off on power. 4.5 (4.3 rollout) 0-60 is way off.
My previous best was a 4.1 and 4.2 before the CEL issue started, about a 3.9-4.0 with rollout which is more in line with the 3.8 Mercedes claims for the 469hp engine.

I spoke to two people (used car manager and my salesman) at the dealership I bought it from and they said they will make it right.
They are 60 miles away, so I told them if they are willing to pick it up and bring it back I would give them a shot at it.

I still think they are missing another problem and only dealing with the coolant system. They are not even looking at the other codes I provided.

I do notice the CEL seems to come on when I put in my Individual mode or Sport Plus, makes me wonder if there is a tune on this car maybe based on mods that may previously been on the car?

More to come.....

 

Asking for sake of completeness, do you think you might be too picky? A couple of tenths on 0-60, does it really matter? Does the average consumer have the ability to properly and consistently measure 0-60 time?

 

That is a good possibility that I have thought of.

However, 4.1-4.2 like I ran when the CEL was not on is close enough, but 4.5-4.8 is definitely way off.
The dragy is spot on with results.

Usually if a manufacturer and/or magazine claims a number I can replicate or beat it, 4.5 (4.3 rollout like the magazines use) is way off, about 50-75hp.
However, if the check engine light was not on and that is how the car ran, I would be OK with it. Sure, it would be a slow GLC63, but as long as there was nothing mechanically wrong I would be fine.

If other people on this forum were having the same issue I would feel better, but this seems to be something I cannot find on any forums.
I have searched.

 

The service department called me today and they confirmed the car is not running right.

They pulled all the codes and are:

1 - Replacing the thermostat
2 - There is a boost pressure leak and they are going to fix that also.

 

The car is done and being brought back tomorrow....

Shlick96 on the C63 w205 forum, you are the man with great advice.

1- they replaced the cam magnets while they were doing the work.
2 - they replaced the thermostat
3 - they found boost leaks at the crank case and other leaks while they were in there, so they replaced all the lines.

The tech told the sales manager I will be very pleased and that is is an animal now.
They said it was not making much boost before and it was performing terribly when they got it.

Will update when I get to drive it.

 

I got it back this morning, it is rainy, but the car feels spunky.
Also, for the 1st time my temperature gauge is 208.

Here is the work that was done, pretty extensive.

 

How the f did all that get past the CPO inspection? Maybe it was remotely inspected over Zoom due to COVID protocols

Looks like you found a great dealer and service department though, they really went through that car thoroughly.

 

I said that from the beginning.
Just know, when buying CPO it might not really have been done, but the CPO warranty has you covered even if not.
My car is still under the factory warranty until the end of 2023, the CPO will take that though 2024.

 

0-60s are now in the 3.85 range with rollout and 60' times are 1.90.

Before the work was done on the car the best it did was a 4.25, and towards the end, no better than 4.3s-4.5s.
Car was definitely down over 40-50hp.