More subframe stuff

[luciano136]

With all the talk about subframes recently, I checked my car again and compared with pics from 2.5 years ago (coincidentally the supercharged years). The spotwelds look a little deeper but it might just be an optical illusion. Not sure. I think it's the same

Dec 22nd 2006


Aug 7th 2009

[Randy Forbes]

That looks like a rust-ring around one of them. That's not good.

[Kenn]

In the second picture, there's a smear of something the same color as the "rust ring" to the left of the spot weld on the left side of the photo. On the weld on the right side, there's also some of that color. The color isn't quite like rust, either, although that could just be the way the photo turned out with flash. I'm thinking it might be something else that got down into the spot weld and was wiped out, mostly.

[Z3RO 2 6T]

Everytime I read one of these I get nurvious. If its gunna happen it will happen. Just wait till you here the creaking

[luciano136]

That looks like a rust-ring around one of them. That's not good.

That's what I thought at first but it doesn't look quite that dark. It kind of looks like the sticky stuff on the bottom of the carpet. I looked under the car but didn't really see anything worrisome. Time will tell I guess...

In the second picture, there's a smear of something the same color as the "rust ring" to the left of the spot weld on the left side of the photo. On the weld on the right side, there's also some of that color. The color isn't quite like rust, either, although that could just be the way the photo turned out with flash. I'm thinking it might be something else that got down into the spot weld and was wiped out, mostly.

It's something sticky; like some sort of glue.

Maybe I should try to clean out the spotwelds. If it comes off easily, it shouldn't be rust.

[knievil]

Looks the same before and after. The rust ring one also looks the same from the photos.

[luciano136]

Looks the same before and after. The rust ring one also looks the same from the photos.

At least some peace of mind

[budman54]

I asked for some info (help) a couple of days ago w/r/t the 'diff mount' issue that I began reading about and I'd like to say 'thank you' to the folks that responded. I was reading more on the subframe thread this evening and noticed the pictures that were posted here, so I checked out my trunk and I found the same thing as is in the posted pictures. I don't think mine are quite as severe, but they are definately noticeable. Is this situation really dangerous? I am pretty confused at this point. I don't notice any abnormal noises, creaking, etc. Are these welds going from the trunk pan to the subframe? Is this a different problem than the differential mount problem I have been reading about? I am thinking about going back to the dealer (used cars, primarily BMW) that I bought the car from and placingthe problem in his hands, I just need more information...

Thanks for any help...

[tracecom]

I asked for some info (help) a couple of days ago w/r/t the 'diff mount' issue that I began reading about and I'd like to say 'thank you' to the folks that responded. I was reading more on the subframe thread this evening and noticed the pictures that were posted here, so I checked out my trunk and I found the same thing as is in the posted pictures. I don't think mine are quite as severe, but they are definately noticeable. Is this situation really dangerous? I am pretty confused at this point. I don't notice any abnormal noises, creaking, etc. Are these welds going from the trunk pan to the subframe? Is this a different problem than the differential mount problem I have been reading about? I am thinking about going back to the dealer (used cars, primarily BMW) that I bought the car from and placingthe problem in his hands, I just need more information...

Thanks for any help...

I, too, bought a Z3 before I knew there was any such thing as a "sub-frame issue" and I, too, am upset about the possiblitity of facing a major repair cost. As a newcomer here, I'm not the most knowledgeable about this issue, but, like you, have read a lot about it and formed some opinions.

1. In the beginning, it's not dangerous. I have not read of a single accident being caused by this problem. It seems to be a progressive deterioration of the spot welds followed by a failure of the differential mount and separation of the trunk floor. Presumably, the differential could eventually detach from the frame of the car and cause an accident. Long before that could happen, there are numerous warning sounds coming from the rear of the car. While there may have been accidents caused by this issue, I have not read of any and conclude that they must be very rare.

2. Yes, the spot welds rusting out and detaching are related to the failure of the differential mount.

3. I bought my Z3 from an individual and currently, it shows absolutely no sign of differential mount or spot weld trouble, but even if I had found a major issue, I don't think I would have gone back to the PO. In individual-to-individual deals when the buyer has every opportunity to have the car inspected, I consider it "caveat emptor," but I think dealers should be held to a higher standard. So, I think that if you can get some help from the dealer, you should do so, and the longer you wait, the less chance you have. If I had bought a car from a dealer that showed signs of the problem, I would have tried to completely get out of the deal and let the dealer have the car back.

4. There is a lot of discussion about whether the issue will eventually affect all or most Z3's. I don't know the answer, but I think that once the problem starts, it will continue unless repaired. The potential for problems is there on all Z3's because it is a very poor mechanical design. The very idea of supporting the differential on only one side with a piece of stamped sheet metal spotwelded to more sheet metal is ridiculous.

5. I find that the Z3 contains a lot of very poorly engineered parts: the seat belt guides, the glove box door, the power windows, the o-rings used to retain the arm rest covers, the water pump, the seat bushings, and more that I can't think of at the moment or simply don't know about yet.

6. The car is a blast to drive and I love driving it, however the worry about the potential for major repair costs outweighs the fun (for me) and if I had it to do again, I would buy something else. If you are similarly worried, perhaps you should return the car.

Just my opinions. YMMV.

[SunzOut]

I, too, bought a Z3 before I knew there was any such thing as a "sub-frame issue" and I, too, am upset about the possiblitity of facing a major repair cost. As a newcomer here, I'm not the most knowledgeable about this issue, but, like you, have read a lot about it and formed some opinions.

1. In the beginning, it's not dangerous. I have not read of a single accident being caused by this problem. It seems to be a progressive deterioration of the spot welds followed by a failure of the differential mount and separation of the trunk floor. Presumably, the differential could eventually detach from the frame of the car and cause an accident. Long before that could happen, there are numerous warning sounds coming from the rear of the car. While there may have been accidents caused by this issue, I have not read of any and conclude that they must be very rare.

2. Yes, the spot welds rusting out and detaching are related to the failure of the differential mount.

3. I bought my Z3 from an individual and currently, it shows absolutely no sign of differential mount or spot weld trouble, but even if I had found a major issue, I don't think I would have gone back to the PO. In individual to individual deals when the buyer has every opportunity to have the car inspected, I consider it "caveat emptor," but I think dealers should be held to a higher standard. So I think that if you can get some help from the dealer, you should do so, and the longer you wait, the less chance you have. If I had bought a car from a dealer that showed signs of the problem, I would have tried to completely get out of the deal and let the dealer have the car back.

4. There is a lot of discussion about whether the issue will eventually affect all or most Z3's I don't know the answer, but I think that once the problem starts, it will continue unless repaired. The potential for problems is there on all Z3's because it is a very poor mechanical design. The very idea of supporting the differential on only one side with a piece of stamped sheet metal spotwelded to more sheet metal is ridiculous.

5. I find that the Z3 contains a lot of very poorly engineered parts: the seat belt guides, the glove box door, the power windows, the o-rings used to retain the arm rest covers, the water pump, the seat bushings, and more that I can't think of at the moment or simply don't know about yet.

6. The car is a blast to drive and I love driving it, however the worry about the potential for major repair costs outweighs the fun (for me) and if I had it to do again, I would buy something else. If you are similarly worried, perhaps you should return the car.

Just my opinions. YMMV.

Nice summary, except for point 2.

The spot welds fail, allowing moisture in and you see a rust "ring". From what Randy (and others) has seen, they do not fail due to rust in the first place. The failue is a stress related.

[TexaZ3]

To be honest, I'm not worried about the subframe issue at all. I had two Z3 Roadsters in the past (owned them for over 5 years total) and never even heard of the subframe issue. Drove the hell out of them. So, if it will fail, so be it, I will deal with it then. For now, I will just enjoy my car for what it is and be happy.

[Car54]

You guys that are new to the Z3 community...give it time and don't dwell on this. As stated earlier, it happens slow. Hell look at Luciano going 2.5 years between inspections and he has a supercharger. If you're really that concerned, spend a few hundred and have the rear end reinforced. The fix doesn't have to cost you multiple thousands to prevent either. Enjoy your car, learn to trust it, and focus more on the insignificant things like the glove box and seatbelt guides.

[amancuso]

Rear subframe issue wayyyyyy overblown. My friend has had his Z3 for six years and he beats the crap out of it. Not even 1 sign of RS issues.

[Mpyre]

In the last pic there seems to be something on the diff mount. That is the exact spot I first noticed a problem on mine!

[Car54]

I have done about 15 track days and 15 autocrosses AFTER I noticed this:



I drilled it out (to stop it) because I had the diff out for other things and did another 20 or so track days and 15 or so autocrosses.

In the last pic there seems to be something on the diff mount. That is the exact spot I first noticed a problem on mine!

[tracecom]

To be honest, I'm not worried about the subframe issue at all. I had two Z3 Roadsters in the past (owned them for over 5 years total) and never even heard of the subframe issue. Drove the hell out of them. So, if it will fail, so be it, I will deal with it then. For now, I will just enjoy my car for what it is and be happy.

Your attitude is the right one, however my nature is to worry. I'm trying to just enjoy the car (and fix the little stuff that I can), but it's not easy for me.

You guys that are new to the Z3 community...give it time and don't dwell on this. As stated earlier, it happens slow. Hell look at Luciano going 2.5 years between inspections and he has a supercharger. If you're really that concerned, spend a few hundred and have the rear end reinforced. The fix doesn't have to cost you multiple thousands to prevent either. Enjoy your car, learn to trust it, and focus more on the insignificant things like the glove box and seatbelt guides.

Good advice and I am trying to follow it.

Rear subframe issue wayyyyyy overblown. My friend has had his Z3 for six years and he beats the crap out of it. Not even 1 sign of RS issues.

I sincerely hope you are right. In some ways, I wish I didn't know the issue existed. Ignorance might be bliss.

[bob3275]

I noticed some questionable spot welds on my 1998 Roadster shortly after buying it and after then reading about it in here. I was not aware of the problem when I bought it. I have mine "fixed" for now with a small piece of angle iron under the car with several bolts running up through it to a metal plate that was epoxied in, in the trunk, under the carpet. It was a much cheaper fix than Randy's although I'm sure I'd sleep better at night if I would have him install his kit in my car. Maybe someday, that will happen. For now, I keep my eye on it and with how it's currently done, unless the bolts break which is highly unlikely and unless the forces somehow pull a fairly large metal plate right through my trunk floor, which is even more unlikely, I believe it will stay fixed. The work was done by someone very familiar with the problem, as he has worked on all types of BMW repairs and maintenance for many years. Personally, I believe different welding spacing or a different welding technique at the factory could have resulted in this issue never surfacing in the first place.

[JWin]

I sincerely hope you are right. In some ways, I wish I didn't know the issue existed. Ignorance might be bliss.

No. Awareness is empowering. Just take a minute once a month to do a quick check. Odds are you won't have an issue but if you do you can catch it before it's actually an issue.

[budman54]

To everyone who has chimed in: Thank you!!! You folks are great. Very professional. This is my 4th BMW; and everytime I leave, I just somehow figure a way to come back. When I bought my first one, the dealer (same one that I bought this M roadster from) told me that these cars have soul. He was right. I love them. My legacy is '87 535IS-A red/tan; '89 525 I black/black w/many upgrades-set up for track; 94 318 I boston green/tan; and now this '99 M roadster black/black. I have checked out the spot welds in the trunk again and they are very similar to the pictures posted in this thread, but not quite that developed. I have also contacted Turner Motorsport (Amesbury, MA) and talked to their repair shop about this problem. They said that they do not have a reinforcement kit for this problem, but that they are specialists with the E-46 subframe problem. Thay have engineered a kit for those and will be able to perform acceptable repair work on mine. I think that I will drive the car, keep checking the welds, and then bring the car to them at the end of my driving season (November) and leave it with them to do the work as well as upgrade the bushings and suspension etc at the same time. I would love to gowith Randy, but it's just not practical based on distance...
Does anyone have experience with Turner?

Thanks to all of you.

One more thing: to CAR 54: I solved the problem of the glove box and the seatbelt guides. I put an umbrella-short one under the glove box near the console as a 'prop'. The GB doesn't move at all now. Second, I used a large spring clip on the SBG and it works fine now...I know, kinda like turnng the radio up louder when you hear 'funny noises!'

Thanks for everything. Please keep thecomments coming, as well as ideas for my suspension upgrades...

[luciano136]

In the last pic there seems to be something on the diff mount. That is the exact spot I first noticed a problem on mine!

I noticed that too but man, it is REALLY microscopic! Anyone that looked under their car, will realize that the mount itself is already small, so that hairline you see is barely visible. I'll keep an eye on it but I don't think there is reason for concern yet.

On the spotwelds, I think they might be the same as 2.5 years ago. On Sunday, I'll try to inspect the spotwelds further to see if it's actually rust or just dirt/glue. If it's rust, yeah, then my subframe is starting to go...

[Randy Forbes]

To everyone who has chimed in: Thank you!!! You folks are great. Very professional. This is my 4th BMW; and everytime I leave, I just somehow figure a way to come back. When I bought my first one, the dealer (same one that I bought this M roadster from) told me that these cars have soul. He was right. I love them. My legacy is '87 535IS-A red/tan; '89 525 I black/black w/many upgrades-set up for track; 94 318 I boston green/tan; and now this '99 M roadster black/black. I have checked out the spot welds in the trunk again and they are very similar to the pictures posted in this thread, but not quite that developed. I have also contacted Turner Motorsport (Amesbury, MA) and talked to their repair shop about this problem. They said that they do not have a reinforcement kit for this problem, but that they are specialists with the E-46 subframe problem. Thay have engineered a kit for those and will be able to perform acceptable repair work on mine. I think that I will drive the car, keep checking the welds, and then bring the car to them at the end of my driving season (November) and leave it with them to do the work as well as upgrade the bushings and suspension etc at the same time. I would love to gowith Randy, but it's just not practical based on distance...
Does anyone have experience with Turner?

Thanks to all of you.

One more thing: to CAR 54: I solved the problem of the glove box and the seatbelt guides. I put an umbrella-short one under the glove box near the console as a 'prop'. The GB doesn't move at all now. Second, I used a large spring clip on the SBG and it works fine now...I know, kinda like turnng the radio up louder when you hear 'funny noises!'

Thanks for everything. Please keep thecomments coming, as well as ideas for my suspension upgrades...

Ask the guys at Turner if they'll install one of my kits for you.

They approached me about using one of my pictures for their website...

[budman54]

Will do Randy...I'll be happy to and I'll let you know the outcome.

[mpire]

You know, I am well aware of the subframe issues and I bought another Z3. Its too much fun to give up the Z3 for something like this.

Randy is very reasonable, and when I figure out the logistics I will be getting the subframe, engine recall, why not.

[budman54]

Randy:

I contacted Turner MS and they checked out your kit. They said they would definately do the install for me. They are working with their fab guy to come up with a price, how long to do it, etc. I would need to get the kit from you and bring it tothemwhe I want it done. They also said that the diff cover with two ears is preferable and they have them in stock. They recommend going with the two ear cover. Thoughts?

Best regards,

Budman54

[Randy Forbes]

Randy:

I contacted Turner MS and they checked out your kit. They said they would definately do the install for me. They are working with their fab guy to come up with a price, how long to do it, etc. I would need to get the kit from you and bring it tothemwhe I want it done. They also said that the diff cover with two ears is preferable and they have them in stock. They recommend going with the two ear cover. Thoughts?

Best regards,

Budman54

I think that's great, and I will work with them in any way I can to make the installation go as smoothly as possible.

Of course the downside, will be if their installation(s) look better than mine...