[Rawtid]

Ran over piece of metal debris on highway at about 70mph, no way to avoid. Heavy piece of some metal looking pipe, likely fell of truck.

Car is brand new (2 weeks old M240ix), less than 500 miles.
Took it to dealer to inspect same day.

The metal engine cover under-tray has some damage but not too bad. The problem is that one of the bolts that attaches the engine cover to the subframe was hit directly and its now bent (see attached pic).

BMW mechanic advised I contact my insurance and have them authorize front subframe replacement, as there could perhaps be some hidden damage to the subframe, since the impact was hard enough to bent the bolt that screws into the subframe itself.
Also might be issue if I have to remove the metal cover in future, as it could be a problem putting it back on the car.

On the other hand the car seems to drive ok, and I'm not thrilled with having to replace subframe on 2 week old car, plus all the crap that goes with it (insurance deductible, renting another car, accident on car report, insurance increase, etc....)

So I guess the question is, assuming you know what you are talking about, it this severe enough to warrant full subframe replacement just because 1 bolt that attaches the undertray cover is bent?

Thanks for any advice !

[RockCrusher]

Originally Posted by Rawtid

Ran over piece of metal debris on highway at about 70mph, no way to avoid. Heavy piece of some metal looking pipe, likely fell of truck.

Car is brand new (2 weeks old M240ix), less than 500 miles.
Took it to dealer to inspect same day.

The metal engine cover under-tray has some damage but not too bad. The problem is that one of the bolts that attaches the engine cover to the subframe was hit directly and its now bent (see attached pic).

BMW mechanic advised I contact my insurance and have them authorize front subframe replacement, as there could perhaps be some hidden damage to the subframe, since the impact was hard enough to bent the bolt that screws into the subframe itself.
Also might be issue if I have to remove the metal cover in future, as it could be a problem putting it back on the car.

On the other hand the car seems to drive ok, and I'm not thrilled with having to replace subframe on 2 week old car, plus all the crap that goes with it (insurance deductible, renting another car, accident on car report, insurance increase, etc....)

So I guess the question is, assuming you know what you are talking about, it this severe enough to warrant full subframe replacement just because 1 bolt that attaches the undertray cover is bent?

Thanks for any advice !

That's unfortunate.

I have some experience with road debris and dealing with the aftermath.

My goal is to have the car repaired to its pre collision condition as best as humanly possible. And every time there have been no subsequent problems.

Thus my SOP is to take the car in to a dealer and let the (ideally senior/most experienced) tech decide what's the right repair.

This has worked well for me.

In this case....

I would certainly replace that metal tray. It serves as a stiffener and being bent may affect alignment of what it bolts to. It can also prove to be difficult to remove/install.

(My Boxster had a similar metal tray.)

After some thought on this while at first I thought I'd write/offer my opinion that the original sub frame could be left in service, I can't do that.

I'm not a professional auto tech. In your case I would agree with the tech and replace what could be any compromised components, even a sub frame.

Not much you can do about the fact the car (may have) this on its car history. I document the damage with pics. I have the damaged repaired as per a professional tech's advice, and use factory parts. I save the repair paperwork.

When the time comes to sell the car I can show the prospective buyer the true extent of the damage, the completeness/correctness of the repair.

At some point a relatively minor accident -- one in which the damage repair involved just replacing the damaged components vs. more involved repairs -- counts for little. Used car buyers are more concerned with price and condition -- proper servicing, lack of mods, and all systems working -- rather than a relatively minor accident some years prior.

In the meantime, after the accident repair, and until you go to sell the car, there are no issues/complications arising from a less than correct repair. Nothing worse that skimping on a repair and living with the aftermath/consequences.

[Pentland]

I wouldn’t replace it. It ain’t going to fall off or impair performance.

I never owned a boxer so I can’t mention it in almost every reply I write. Sorry.

Also sorry of the short reply.

[Rdurty2]

Originally Posted by Pentland

I wouldn’t replace it. It ain’t going to fall off or impair performance.

I never owned a boxer so I can’t mention it in almost every reply I write. Sorry.

Also sorry of the short reply.

Just wanted to say that I always love your posts.

[RockCrusher]

Originally Posted by Pentland

I wouldn’t replace it. It ain’t going to fall off or impair performance.

I never owned a boxer so I can’t mention it in almost every reply I write. Sorry.

Also sorry of the short reply.

Mentioned the Boxster because I experienced some similar experiences with it and being a German sports car felt it more applicable to the OP's situation than say my Datsun 510 or my D200 Dodge pick up truck.

I had intended to post a pic showing the damage to the component of interest but I couldn't find the picture and forget to re-edit my post.

My SOP is to replace any component damaged (even bent) that is held on by bolts. The presence of bolts implies it is more than just there for cosmetic reasons.

The incident is a miserable event. Makes one sick.

But as I mentioned the goal is to repair the car back to its pre collision condition and knowing it is repaired to this standard allows me to put the unfortunate incident behind me. This may not be possible if one seeks a sub standard repair. There can be doubt on the correctness of the repair and this can keep the repair, the whole unfortunate incident, on one's mind going forward.

I prefer to avoid this and resume making more pleasant memories going forward.

While your reply is brief it is none the better for it as you have no authority to judge the damage and consequences of your repair advice. I advise the OP go by what a professional tech tells him to do.

[Pentland]

Originally Posted by Rawtid

So I guess the question is, assuming you know what you are talking about, it this severe enough to warrant full subframe replacement just because 1 bolt that attaches the undertray cover is bent?

Thanks for any advice !

Originally Posted by RockCrusher

While your reply is brief it is none the better for it as you have no authority to judge the damage and consequences of your repair advice. I advise the OP go by what a professional tech tells him to do.

The OP specifically stated, “assuming you know what you are talking about…”

You don’t know what my background or areas of expertise are so you have “have no authority to judge” me. FWIW, I wouldn’t have responded had I not met the OPs criteria.
You on the other hand have confessed always to rely on “a professional tech” so certianly have no expertise to share. Your opinions are anecdotal.
The fact the OP has already done what you suggested and isn’t comfortable with the advice speaks volumes.

[Littlecoupe]

I haven't had a reason to get underneath my own M240i, but assuming that skid plate is only held by bolts and does not require removal of any other adjacent components, if it was me I would have the skid plate removed to examine the subframe and determine if there is any structural damage. I have experience in heavy manufacturing (non-automotive) and I have seen plenty of instances where the fastener can bend, but the structure in which is it attached is completely unharmed. If nothing else, you'd pay for some labour (hopefully only an hour or two) and a replacement bolt, then leave knowing you're good, less the scuff on the skid plate.

I would personally want to know if the subframe was damaged. Without having a schematic, I can't be sure what else that bolt secures besides the skid plate to the subframe. A bend in structural component like a subframe can lead to stress fractures and failure after being put under repetitive stress. Contrary, to Pentland's point, it may be inconsequential and result in no long term harm to the vehicle. It's really your call whether you pursue diagnosis.