Car question: rear bumper damage

Hi,

I recently got rear-ended in my 1999 Pontiac Grand Prix. I was the third in line of a 3 car fender bender - they guy two cars behind me hit the girl behind me, and she hit me. The front-end of his car and rear-end of her car were both severely damaged, but my rear-end and her front-end only have minor scratches.

The guy’s insurance company took full liability and sent me a check for the estimated repair costs which include replacing the rear bumper cover. They indicated that they would cover any additional damages to the bumper underneath once a mechanic tore it down to replace it.

Now, the damage to the bumper cover is vey minimal. In fact, a mishap I had with shopping cart left a bigger scratch, which I never fixed. I’m thinking of just cashing the check and not getting anything fixed, as I can live with the scratch, and can certainly use the $.

My question concerns the possibility of any underlying damage to the bumper itself. My estimator said it would be impossible to tell if there was any without removing the bumper cover. Can anyone enlighten me as to what exactly might be damaged under there, and whether or not a compromised bumper represents a safety issue?

I estimate we got hit at around 5 MPH. It felt like quite a jolt, but given only the minor scratch, I can’t imagine the car has any issues.

Is it worth checking out (and eating up the insurance check in labor charges)? Anyone have any similar experience? I’d hate to spent several hundred dollars to fix a scratch, if that is the only thing wrong with it.

IANACE, but I once got rear-ended in a 94 Grand Prix. Both the lights for the licence plate got crushed, but nothing else was even scratched.

Under the bumper is what looks like a big block of styrofoam - you can see a bit of it if you crawl under the car. It looked okay, so I charged the guy something like 100$, bought new lights and sockets for 50$, and replaced them myself. Woulda cost at least 300$ for the shop to do even that, so I figure everyone’s better off.

When my mom got rear-ended in a different car, the plastic brackets that look like they help hold the bumper on broke. My dad had put a hole in the front bumper a while earlier doing odd things in an alley, so we got the front one replaced instead and put some of the handyman’s secret weapon under the back.

Of course, if someone who knows wants to say that those blocks of foam must be in pristine condition all the time, listen to them.

Personally, I’d pocket the money. Sounds like the bumpers are fine.

Modern cars have a plastic bumper cover that will deform then go back into its original shape during an impact, making it impossible to tell what kind of damage has been done underneath. The bumper cover may look fine now, but there’s no way of knowing if you still have a functional bumper underneath without taking it apart. I doubt that much more than the bumper was damaged, but you may be effectively riding around without a rear bumper at this point.

I wonder if, in fact, the collision occurred at less than 5mpg. If she was stopped before being hit, it may be the case. If so, check the 5mpg bumper regs. I think they were in force for 1999. This means that your bumper would have to protect to 5mpg without any repairable damage. Maybe answers it.

When my car got rear-ended, there was very little visible damage to the bumper. Just a small dent. However, the total repair bill was $1,700 to replace it and fix the internal damage. (Paid by the other driver.) Although the bumper looked fine, it was in fact broken and needed to be replaced.

I’d think the labour costs alone, just to see if there is any damage would be pretty small compared to the costs of actually fixing that damage if it shows up later and you have to pay the costs yourself.

It’s also a safety issue. You need to be sure the bumper is still intact internally and protecting you like it should. Get it checked by a mechanic.

Lionel - how hard were you hit?

I was ready to pocket the cash (A/C needs fixing, anyway) until I read yours. My service manager tells me the mechanism underneath is mostly styrofoam. When I told him 5 mph he said it would be fine (not worth fixing).

I’m not sure, but more than 5mph. No other damage except the bumper though.

Mine didn’t have styrofoam in it though. There was some kind of internal ‘shock absorber’ system that had done it’s job, but needed to be replaced after that.

Sounds like you have a completely different system, so I don’t want to worry you for no reason. It’s just that to look at it, my bumper just had a little ding in it when in fact all the internal stuff was shot. But if your mechanic thinks it’s OK, then I see no reason not to believe him.

Energy absorbing bumpers can be badly damaged internally in a 5 mph crash. In fact, they are designed to sacrifice themselves for your safety. It’s a single-use product. If your bumper has absorbed a crash, it might provide no protection in the next crash.

Some bumpers use plastic foam, as Nanoda said. The bumpers we built at Guide for General Motors used a crushable plastic “egg crate” piece, with the holes about big enough to hold a fat cigar. The core of the bumper was a steel box beam, and the impact absorber bolted to that. The flexible fascia (cover) was riveted over that.

The rules have changed, here is some info from the NHTSA

you can and will damage the bumper and unlying structure in a 5 mph accident. How much damage and what the repair costs will be vary with the make / model of car, and just how hard the hit was. Here is a page detailing repair costs on some current SUVs.

AskNott - are the GM bumpers you are familar with subject to the “1 use rule”? I suppose I should have it looked at after all.

However, I find it hard to believe the service manager would recommend not worrying about it based on the info I glean from the last 2 posts.