FJ Engine Bay Body Rips

Thai

Thai

Elite Member
Hey all,

This is an interesting thread over at FJ forum: http://www.fjcruiserforums.com/forums/problems-dealer-service/33440-engine-bay-body-rips.html

Apparently, this is happening more often on FJs with aftermarket bumpers. However, on page 10, Bellydoc wrote an extensive analysis of the issue.

It's worth reading for those who are thinking about aftermarket bumpers. However, as some have noted (see POLL RESULTS), this does happen with stock bumpers too.:( I would look into the 4runner's engine bay if you off-road often...just to be sure.

It may be related to build dates too..."According to our (not-so-scientific) comparisons within this thread, the pre 01/07 build models are the units that have been tentatively identified as more susceptible to cracking. While the post 01/07 models are showing little, if any, problems."

BTW, this problem is apparently a known issue on Land Cruiser Prado overseas.
 
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Here is a quick summary to the whole thread by 4xx4:

"As for a summary, there are a few viable theories as to what is causing the premature collapse of the crumple zone on the inner fender. So far, we have determined that the cause is NOT specific to lifted rigs or aftermarket bumpers. In fact, some heavy wheeling members have reported no problems, and contrasting that, we have some light wheeling folks who report minor to major ripping. There is no concrete pattern.

As far as the build date, and so far this is just theory, some light has been shed on a difference in the inner fender stamping and spot welds that may be reason as to why the newer FJ's have not reported the same drastic effects from wheeling that the '06 builds have. There has also been very convincing arguments against drawing a conclusion based on a few "new" holes in the general area.

So as you can see, we have not found THE solution to our problem. Some fine members have brought this to Toyota's attention but we are still in the early stage's of receiving any acknowledgemnet from them.

Hope this helps, mlovett, it's the best I can do."
 
After reading just about the entire threat, it seems like a serious design flaw in the FJ unrelated to Mods being that the poll shows that over a 1/4 of the stock vehicles also have the problem. I see class action lawsuit coming a mile away with possibly the demise of the FJ as it looks and is designed today.
 
Don't tell anyone this!! Last time i mentioned Tacoma's weak frame or axle issue, a few on here blasted me for exaggeration and imagining up stuff!:D

IMHO, Toyota is trying to do too many things with one platform. With one platform, the models range from luxury SUV (GX470/4runner) to off-roader (FJ Cruiser) to truck (Tacoma). I think that this platform is excellent for a midsize SUV (GX and 4runner). However, Toyota is asking a bit too much of it when it used the same platform in the FJ where aftermarket mods and brutal off-road abuse are the norm. I don't think that Toyota even changed the frame at all from Prado to FJ Cruiser. When you start to add aftermarket gears (heavy ass bumpers, high lifts, big ass tires) and severe off-road abuse (Rubicon trail for example), you are truly testing the limits of the platform.
 
Wow that pic of the fenders tearing under the hood of the FJ is amazing....I don't think I've ever seen anything like that....:awais:

I remember when Toyota first released the Tundra they claimed that they used X amount of cross members which caused their frame to be the most rigid in it's class. Now I don't know the inner working of how Toyota researches and develops it's frames, but I'm guessing that they use the same methods for all the different frames they offer.

That being said.....

It has been my experience that a certain amount of frame flex is good for a frame. It allows movement under load to allow the frame to withstand the stress of the load it is under. So having the most rigid frame is not necessarily they best thing. Ford, Chevy and Dodge have been building large trucks for far longer than Toyota has, and I'm sure in that time they have seen many different frame situations and have determined what works and what doesn't.

Now I'm not saying this is necessarily the case, but it could be. Maybe Toyota is using such a rigid frame in the 4Runner/FJ/ Tacoma that it is not allowing flex.....so the frame tries to flex to relieve stress on itself and it can't....so over time it develops weak points and then finally fails at the weakest point on the frame. Which appears to be the front section.

Or maybe designs and tolerances that work on the larger Tundra/Sequoia frame are trying to be used on the smaller 4Runner/FJ/Tacoma frame and due to the differences in size and geometry those designs and tolerances are not working with the smaller frame.

It seems to me that there has to be a serious design flaw for a frame to fail in such a short period of time. I mean the FJ has only been available for 2 or 3 years correct, :confused:
 
The problem is that the frame does indeed flex. Now, the question is...is it the frame that flexes TOO MUCH thus resulting in body damage OR is it the body that cannot withstand the minimal flex of the frame??? All frames flex...some more than others. I think that this is the problem with this issue...no one knows exactly what caused it nor the solution for it. And i am sure that Toyota is aware of this issue.

My guess is that the body is the weak point, not the frame. The frame is widely used and is strong from everything that i have read. Maybe Toyota underestimated the stress at the inner fender in an off-roader like the FJ? I think that the crack/ripple is occuring at the crush zones...which, i assume is inherently weak to begin with.
 
Good question. I would definitely look if you do any moderate off-roading.

BTW, i have merged threads.
 
Originally posted by Thai
The problem is that the frame does indeed flex. Now, the question is...is it the frame that flexes TOO MUCH thus resulting in body damage OR is it the body that cannot withstand the minimal flex of the frame??? All frames flex...some more than others. I think that this is the problem with this issue...no one knows exactly what caused it nor the solution for it. And i am sure that Toyota is aware of this issue.

My guess is that the body is the weak point, not the frame. The frame is widely used and is strong from everything that i have read. Maybe Toyota underestimated the stress at the inner fender in an off-roader like the FJ? I think that the crack/ripple is occuring at the crush zones...which, i assume is inherently weak to begin with.
Click to expand...

Ok that makes sense....;):

I also read the link about the Tacoma that had the frame fail around the shock hoop. Being these are the same frame I was looking at that issue as not having enough ability to flex and exposing a weak point.

I guess my post was more towards this issue than the body of the FJ tearing.
 
Thai said:
Good question. I would definitely look if you do any moderate off-roading.

BTW, i have merged threads.
Click to expand...

Thanks Thai...didn't realize there was already a thread on this...don't hang around here as much as I use to...
 
didn't read all the post. I had an 2002 civic at one time and at 50k miles the tranny blew. (out of warranty) Dealership would not cover the problem. After one week of countless hours on the phone with honda reps they covered the problem. I only had to pay labor ($278)

Just keep at 'em. I also found this line seems to work "I bought this vehicle for the wonderful reliability rep it has. If I knew it would crap out this quick I would have bought a dodge, I will never own another honda and I am only 23. Lots of new cars in my future." Something to that context. Said that and got offered a new tranny.

Good luck
 
11/06 build date, 30k miles (mostly highway plus moderate offroad driving)... inner fenders look perfect, no bulging/cracking/tearing.

I've always told myself that if I see any sign of it, I'm trading it in for a T4R the same day. :)
 
SupraTuRD said:
11/06 build date, 30k miles (mostly highway plus moderate offroad driving)... inner fenders look perfect, no bulging/cracking/tearing.

I've always told myself that if I see any sign of it, I'm trading it in for a T4R the same day. :)
Click to expand...

Sounds like it needs a lot more off road time so you can get a 4Runner :D
 
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