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Old 02-13-2011, 09:37 PM
Hqqi Hqqi is offline
Registered User
Location: Philadelphia
Join Date: Feb 2011
Posts: 2
Mein Auto: BMW
Should I go for this 07 M6?

Planning to purchase a 2007 M6 with a mileage a little bit under 36K+ miles (SMG transmission, 2 previous owners (I will be the 3rd), no accidents (yet to confirm it with a technician & carfax). Went to see it on Saturday and I liked the car a lot. The only thing that worried me was the fact that the cold air intake (CAI) was modified (afe air filter) and also the stock exhaust was replaced (I am attaching the picture of the engine I took). The car hasn't been used lately so especially the engine compartment was very dirty. Also, the "Service Engine Soon" light was on inside and when I checked the on-board computer it showed increased emissions as an issue. I have done some reading online and it looks like the aftermarket CAIs cause irregular/more air to pass through mass air flow (MAF) sensor, as a result triggers the service engine light (because of the possible lean combustion that will occur in the chamber) or sometimes the oil from the aftermarket CAIs clog the MAF sensor causing the issue. The owner also told me that as soon as he installed the aftermarket CAI it triggered the "Service Engine Soon" light.

The car is supposed to be still under 4 year warranty, although the owner will let me know exactly when it will expire (hopefully not February). So my questions to you are;

1. Should I walk away from this deal, am I taking too much of a risk, given the modifications and the engine light? I hopefully will use that as a leverage and get a good deal but still do not want to buy a car that I will have to pay to get it fixed every month - especially given the costs associated with fixing an M car.

2. I am hoping that after I replace the aftermarket CAI with the BMW part, the emmissions will settle and the service engine light will go off (if the MAF is not damaged). My question is, throughout the time that the car is still under warranty, will BMW give me hard time because of the aftermarket exhaust (and the old aftermarket CAI) that is(was) installed? I am sure even if I install the stock CAI, they will be able to tell there was an aftermarket CAI from the data they have on car's computer and/or by looking at the screws holding the CAI box.

3. It looks like although the aftermarket CAI triggered the "Service Engine Soon" light the current owner did not care and used the car with the warning sign on. From the reading that I have done, as I have stated earlier, the engine is getting more than enough air and this is effecting the stoichiometric burn ratio. Assume he used the car like this for at least 15K miles, has the current state affected the lifetime of the engine? I will take really good care of it from the day I will own it but if the current owner has already ruined the engine, I don't think it will matter.

4. I have also read some horror stories regarding the SMG transmission catastrophically failing without notice. Looking at the mods on the car I don't think the current owner used it at low revs all the time. So assume the car was sometimes(or regularly) pushed to its limits, does it mean that SMG transmission is already close to its lifetime?

5. Given the condition of the car, how much offer should I give to the seller? Assume you were buying the car in the given condition, what would be the maximum value you would comfortably offer given all these risks?

Thank you all for your time. The pictures of the engine are attached.

(Posted this to another forum but got zero feedback so wanted to try my chance here, thank you so much for your time )
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