Last post on Jul 29, 2013 at 9:14 AM
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BMW 5 Series, Sedan, Wagon
#1 of 30 2006 BMW 525i (N52) possible wide spread defect
Jul 27, 2011 (12:38 pm)
This is the message I sent BMWNA 2 days ago. They have still not responded by email or telephone. Are there any other owners out there with low miles that had problems with their timing chains? I'll be contacting the BBB shortly and I assume this might be one of those hidden defects that the company does not want others to know.
I had a recent problem with our 525i. I was driving it and it lost power/died. The car would not restart and no error lights or messages were displayed on the IDrive. I had the car towed home. After the initial check of the vehicle, it showed the crank sensor fault. I noticed a bunch of metal throw off in the oil filter and the vehicle did not have compression in cylinder 2 and 6. I was thinking catastrophic engine failure.
Since I am very familiar with American/Japanese vehicles, I decided to look into the problem myself after getting no response from BMWNA. The car is out of warranty with 85K miles.
The metal throw off was due to the timing chain jumping off of the exhaust cam gear and grinding against the back of it. The cause of the problem was the two aluminum screws under the cam shaft gears. Both heads were broken off and one made its way up the chain getting caught in the chain and gear. These screws are aluminum. I donít know if this is a common problem but for the bolts to break it would be due over torqued/tighten bolts or extreme pressure from expanding/contracting of the magnesium vs aluminum. I suspect over tightening. The other broken bolt head is still some where in the bottom of the oil pan. The exhaust cam gear was chewed up, but still serviceable. I re-timed the car and checked the compression. I got lucky and compression is good so no bent valves. I disassemble everything and now I patiently waiting for several parts. However, I'm still dealing with the broken head that is some where in the oil pan.
I re-contacted BMWNA and the customer service rep took down some information and stated there was nothing they could or would do for me. She noted my concerns to better service future customers and advised me to take the vehicle to the dealer. I asked to speak to some else and she stated she was only in customer service and no one there could assist me. I'm a bit surprised, because I have always had excellent dealings with BMW. I recall a time when BMWNA representative personally called me to rectify a warranty issue. The dealer did not want to cover the item under CPO. A person from corporate assisted me and earned my loyalty. This is the reason why we currently own 3 BMWs (05 325XI, 06 525i, and 07 335i). I understand car maintenance is a must, but when something is not the fault of the owner should I have to bear the entire cost of the repair. Iím not asking for anything other than consideration or a return call from anyone who has the authority assist me.
#3 of 30 update
Jul 28, 2011 (12:27 pm)
Still no response from BMWNA and I will be filling with NHSTA and BBB to have them look into this problem.
#4 of 30 Re: 2006 BMW 525i (N52) possible wide spread defect [hchi]
Oct 01, 2011 (2:02 pm)
H. Chi --- Did BMW ever respond? If so, I would like to learn what the result was. I have the same problem.
I have a 2006 530 with the N52 engine. Last year, I had a severe oil leak in the front of the engine. The BMW dealer took a look and discovered a broken cylinder head bolt near the oil filter. The estimate to repair (a complete head gasket replacement) was about $3500. After being turned down for an out-of-warranty repair, I took a stab at replacing the broken bolt myself. That fixed the oil leak.
Fast forward to today - - I was replacing my valve cover gasket (another small oil leak) and noticed that there were three other bolts broken off in the same manner as the first one. Turns out there are 4 aluminum bolts that hold the front of the cylinder head to the block (around the valve train galley). One is external; the other three are under the valve cover.
I plan to contact BMWNA on Monday and would like to know if you has any luck.
#5 of 30 2006 BMW 525i (N52) possible wide spread defect
Oct 01, 2011 (3:35 pm)
BMW wanted me to take it to a BMW dealer at my expense. They stated the service writer and their machanic would have to inspect it and then it coulkd be determined if it "might" be covered. However BMW wanted $1500 to look at it and (thousands) to repair it. Better bolts need to be made. They should be made with a steel core like several bolts that the N52 motor has on the outside holding the wire harness. Yes, 4 bolts are included in the replacement kit and 3 of my the heads sheared off. It is clearly a manufactures defect and I would advise you to file with NHSTA and the BBB. If enough others file, BMW might actually be obligated to do something!!! Maybe I can get re-imbursed the cost of my repairs!!!
I have completed the repairs and the car is fine. I ended up spending about $2,000 for specialty tools, parts, and a scanner. Others who are not so mechanic will have to spend a lot more. Let me know if you need any other assistance, but BMWNA was a waste!!!!!!!!!!!!!!!!!!!!!!!!!!
#6 of 30 2006 BMW 525i (N52) possible wide spread defect
Oct 01, 2011 (3:50 pm)
The aluminum bolts are stretch bolts. They are torqued to a specific amount and turned an additional 90 to 180 degrees to properly torque/stretch the bolts. The N52 aluminum head boats required another 90 degrees after the torque values. (BMW repair recommendation) I did not stretch my bolts and I think they were 15 or 10 nms??? About 88 inch pound of torque if I remember correctly. I never recovered one on the sheared aluminum heads and it is still caught up some where in the oil pan. Good Luck
#7 of 30 Re: 2006 BMW 525i (N52) possible wide spread defect [hchi]
Oct 04, 2011 (4:13 pm)
I started with the local BMW dealer and got confirmation that THIS IS A KNOWN PROBLEM with N52 engines. Next I connected with customer service at BMW North America. I worked my way up from first level customer service rep to manager --- same result --- acknowledged that this is a known problem. BMW will cover repairs if under warranty or, in some cases, will cover under "customer goodwill" if recently out of warranty.
Here is my gripe; BMW knows that this is a design problem (versus a maintenance issue) but refuses to repair. If repaired at a BMW dealer shop, it is a $3,000 to $4,000 repair. OUCH!!
#8 of 30 2006 BMW 525i (N52) possible wide spread
Oct 04, 2011 (7:51 pm)
My car was out of warranty and I purchased the car new. I did not buy the extended warranty. I was about 25,000 miles over and when I called BMWNA, they stated there was not much they would do. If I had the CPO warranty or if I was close to the 40K warranty??? Who knows. A known defect, but bmw refusses to repair or correct it. I find it a little disturbing that they would not recall the problem. I guess 50K buyers are small fish. Are they going to repair it for you at no cost?? Good luck and let me know what happens.
#10 of 30 Re: 2006 BMW 525i (N52) possible wide spread [hchi]
Dec 05, 2011 (6:24 pm)
Update - completed repairs a couple weeks ago. Like you, I had to "invest" about $2,000 in parts, speciality tools, etc. Based on BMW dealer estimate, this was about half the cost of dealer repair. All 4 aluminum head bolts were broken off -- the heads popped off. I dismantled the valve chain guide and other parts in search of the bolt heads, however, no luck. I suspect they are in the oil pan. However, I do not have the ability to remove front frame section and lift engine to pull the oil pan! What a pain! Before this, I would have recommended BMW to others, but not now. My ownership experience with Mercedes Benz was much better. I suppose this kind of issue also fuels the recent Audi sales pitch. On the bright side, I am now discussing options with an investigative legal firm.