# 2002 745LI Engine Knocking Noise



## drockstar (Sep 17, 2006)

Hi all,

Just wanted to hear if any of you have heard a knocking noise when the 745 engine is at idle. I have to bring it in to get it checked out, and was wondering if it was an on-going issue. I have searched the forum and found similar threads, but not quite what I was looking for. "Dieseling" may be it, it does kind of sound like a diesel engine at idle. It goes away when I rev it up though. BTW, it has 37,000 miles on it.

Thanks all.


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## gbelton (Aug 3, 2003)

*When Was Your Last Oil Change?*

Sounds like similar thread posts already experienced by many of us...

Lifters, Valves, Pistons clanging... The dealer will be able to resolve it easy, just be sure to produce it for the tech to hear or describe exactly what they must do to repeat your symptoms...

If you don't I am sure you will come back here and post, "They said nothing is wrong".

Good luck


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## drockstar (Sep 17, 2006)

Thank you gbelton. I did let a service writer hear it and he suggested that I get it looked at ASAP. So apparently I am not hearing things. I just bought it as a CPO. Have any of you ever been to the BMW dealership in Fort Pierce, Florida? (Coggin) I bought my 530i from there and the service is just outstanding. If any of you ever have to go to their service department, ask for Derrick Levelston. Amazing service.


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## jbpatel82 (Feb 23, 2007)

Hay, what ever happened with your engine noise issue?? what did the dealer do, i think i'm having the same issue.
thanks in advance
jp


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## gbelton (Aug 3, 2003)

drockstar said:


> Thank you gbelton. I did let a service writer hear it and he suggested that I get it looked at ASAP. So apparently I am not hearing things. I just bought it as a CPO. Have any of you ever been to the BMW dealership in Fort Pierce, Florida? (Coggin) I bought my 530i from there and the service is just outstanding. If any of you ever have to go to their service department, ask for Derrick Levelston. Amazing service.


Excellent!:thumbup: I will definitely look them up when I am in town.

Let us know how it goes when you get a chance.


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## drockstar (Sep 17, 2006)

I will let you guys know. I am taking it in on Wednesday, so as soon as I find out, I will let you know.

BTW, I am getting ready to put the pictures up for the 20" Asanti's. Check it out...


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## drockstar (Sep 17, 2006)

*update*

Well, yhey have had my car for a week. They still don't know what it is. I guess they have been talking to "higher ups" somewhere in the world. I am really nervous now.


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## drockstar (Sep 17, 2006)

*update*

Tomorrow will be 2-weeks. BMW has authorized the dealer to go exploring to find where the noise is coming from. They have now had my car longer than I have... this sucks.


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## drockstar (Sep 17, 2006)

*update*

The techs are telling me that that have cleaned a lot of carbon from the top of the pistons and that 70% of the noise is now gone. They said that they have never seen this before in one of those engines. It seems strange that there was so much carbon that it is creating that kind of noise. They said that the engines are very sensitive and that the previous owner's driving style caused it. Supposedly it is caused by a lot of "stop and go" driving versus interstate driving. Anyway, the latest is that they may be taking the rest of the engine apart for access to the rings to clean it even further. It depends on some sort of diagnostics they are running today. I want my car back, but not until it is running 100%. I told them that as long as they keep me updated, I will try my best to remain patient.

I actually talked to the service manager yesterday, he assured me that my car was in good hands and have been authorized by BMW to do whatever it takes to make it right. That is a little comforting. I will keep you all posted, but it is seeming that this is a very isolated incident and may not be much help to anyone.

Thanx


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## 03745Li-chicago (Oct 15, 2006)

My 04 exhibits this knocking noise as well @ idle. Im gonna be taking it to the dealer early next week. My issue might be a little different than yours. When my car is in park, I dont hear the knock.  When Im in drive @ idle, I hear the knocking. I have a feeling the dealer is gonna *NPF* my concern but im gonna bring it up regardless


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## DenverNoob (Apr 12, 2006)

drockstar said:


> The techs are telling me that that have cleaned a lot of carbon from the top of the pistons and that 70% of the noise is now gone. They said that they have never seen this before in one of those engines. It seems strange that there was so much carbon that it is creating that kind of noise. They said that the engines are very sensitive and that the previous owner's driving style caused it. Supposedly it is caused by a lot of "stop and go" driving versus interstate driving. Anyway, the latest is that they may be taking the rest of the engine apart for access to the rings to clean it even further. It depends on some sort of diagnostics they are running today. I want my car back, but not until it is running 100%. I told them that as long as they keep me updated, I will try my best to remain patient.
> 
> I actually talked to the service manager yesterday, he assured me that my car was in good hands and have been authorized by BMW to do whatever it takes to make it right. That is a little comforting. I will keep you all posted, but it is seeming that this is a very isolated incident and may not be much help to anyone.
> 
> Thanx


could be that the previous owner used inferrior grades of gasoline...which in turn causes much less efficient combustion, leading to carbon buildup. granted these engines can handle a tank or two of lower grade gas, but constant running of said grades can be bad. there are a number of things that can cause this, but that can be one of the more common.


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## drockstar (Sep 17, 2006)

I just heard from my service writer. The diagnostics test were "unacceptable". They are going to tear down the engine.


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## gbelton (Aug 3, 2003)

*No...Not Regular!*

Thanks for the update. I did fear this would be the case. I am sorry to hear about this.

I tell you, people buy these expensive cars and put in REGULAR gasoline pisses me off! The manual says, MINIMUM 91; these people do such a disservice to people like you. You pick up such a nice ride and BAM, you get hit with that kind of crap.

Some additional advice:

Once all is good and you get you car back, use only Shell, Chevron, 76, Texaco, or Phillips. They all use extra detergents to keep your car purring... Of course nothing less than 91 octane should be used at the pump.:thumbup:

If you are unable to get these fueling options please insert a gasoline cleaner from BMW or your local auto store.

From BMW: 82 14 0 413 341 Fuel System Cleaner Plus; 20 fl.oz. bottle

From Local Auto store:*Chevron TECHRON Concentrate Plus Fuel System Cleaner to treat up to 20 Gallons bottle [Link: *http://www.chevron.com/products/prodserv/fuels/additives/concentrate_plus.shtml* ]
*
I use this one every third fill-up.


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## DenverNoob (Apr 12, 2006)

good advice. you can never really keep motor internals TOO clean.


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## drockstar (Sep 17, 2006)

Thanx gbelton. I am sure you nailed it with that comment. The previous guy probably didn't care because he knew it was a lease and would be returning it.


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## love V8's (Mar 11, 2007)

gbelton said:


> Thanks for the update. I did fear this would be the case. I am sorry to hear about this.
> 
> I tell you, people buy these expensive cars and put in REGULAR gasoline pisses me off! The manual says, MINIMUM 91; these people do such a disservice to people like you. You pick up such a nice ride and BAM, you get hit with that kind of crap.
> 
> ...


So my friend has a 04' 745Li. She uses Exxon gas, but it is 93. I use it for my MB E430 and for the Designo S430. So does anyone know if Exxon/Mobil uses these extra detergents like Shell, Chevron, 76, etc. Thanks in advance.


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## drockstar (Sep 17, 2006)

*update - need opinions*

Hi All, I need your opinions...

I just found out that BMW is putting a brand new engine in my car. They want to ship the original engine back to the factory for studying and tests. I am worried that in the future, it may affect the re-sale value of the car. My questions are:

1) If the odometer statement stays the same, would it affect your decision to purchase it?

2) If the odometer changes to reflect the new mileage on the engine, would it affect your decision to purchase it?

Thank you.

D


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## BmW745On19's (Aug 12, 2005)

Both questions, yes, both would affect my decision to purchase. As long as I know how many miles are on the chassis _and_ the engine, however, I wouldn't mind buying it as long as I know why the engine was changed and I know you didn't blow it up due to extremely hard driving, etc.


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## gbelton (Aug 3, 2003)

*Hmmm*



drockstar said:


> 1) If the odometer statement stays the same, would it affect your decision to purchase it?


Yes, because it is a new engine the odometer readings should be accurate.

Once upon a time I worked at a dealership (Mitsu), and when we had to change out an entire engine, the odometer was set a few ticks (100 miles), as required by the manufacturer but the dealer also included a certification that exclaimed the engine was brand new (Replacement from the factory/dealership). Don't know if this make sense to you but that was then (90's) and who knows what they do now...



drockstar said:


> 2) If the odometer changes to reflect the new mileage on the engine, would it affect your decision to purchase it?


See response above.


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