My 2016 4R has been dropping the heat shields between the body and the exhaust system. Just chinsy aluminum shields that rot where they are screwed into the body. The last one I had to remove that was directly over the muffler because the only way to reattach it is to drop the entire system.
Is it really important that I have this reattached? I highly doubt this would be covered under my extended warranty and I also doubt these parts are even available. Any thoughts?

not critical. many people drive without them. dealers will usually rip them off when a customer comes in with a loose or broken shield. reason being is they are probably $100+ to order a new shield.

if you can salvage them I'd try to make them work. if you can't or can't be bothered then it's no big deal. I have never heard of damage caused by the floorboards heating up or surrounding lines heating up because of lack of heat shield. no these shields will not stop grass from catching fire they go above the exhaust not below. the cat heat shield on driver's side is probably the only more important heat shield. yet only one cat is covered

if these shields were so important for safety purposes auto makers would design a better fastening system and not use dissimilar metals which can lead to galvanic corrosion - hence why so many shields drop

the best way to go about this is to buy some nice big m6 fender washers and new stainless steel m6 serrated bolts. you can then put the fender washer and new bolt on there and it will not fall off again. if the fender washer is not wide enough just get some aluminum flat stock and cut to size

I had a couple shields break loose and the above is exactly what I did. for some of the larger broken through sections where I wanted more diameter than a fender washer I used aluminum flat stock 1/8" thick, cuts easy with hacksaw and drilled a hole through the centre

I replaced almost all my heat shield fasteners over the course of a few weeks during the summer/fall after two dropped on me. interestingly enough the shield over the exhaust seemed to have a nice fender washer/nut combo on it already - where none of the others had. Idk why that one came from factory like that.

I ended up ripping them off one by one on my old 2012 T4R. Usually while on the road. When that one above the driveshaft ended up dragging on the driveshaft on the highway it wasn't pleasant.



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YUP! That is how mine decided to drop and make a nasty racket. Good thing I had gloves and could pull off but a real PITA to bend and rip it out. This one over the muffler will not be reattached because the entire system would have to be dropped just to get at it.

As a real bush (or "permanent") fix, one could even worm drive clamp a piece of sheet metal to the exhaust component in question (top side only). The more "corrugated" the metal the better. Yes there would be some conduction w/ this approach, but also some convection, resulting in a heat shield lite result.

Had this issue on my 03 and 08 4th gens, I removed the shields to stop the vibrations and never had any issues with heat or rusting. Just my 2 cents

They're there for several reasons. Obviously they shield/protect critical components from excessive heat such as manifold and head gaskets. They're also there for scientific purposes dealing with fluid physics and thermodynamics.. the idea is to keep the majority of the heat within the exhaust pipe. This increases exhaust flow which allows your engine to breathe more air and perform better. Also it reduces engine bay temperature therefore reducing IAT(intake air temperature). 👽

I'm sure you could come up with an alternative method of attaching that hard to get to shield. I'm assuming it's attached from the top side.. would maybe want to rig it to where you can attach it from the bottom side if you're into a little engineering.

Im pretty sure you can get at it with a swivel socket and ratchet. I didn't have to drop any components on mine. maybe later model years are different though

First off, the muffler sits just under the rear passengers seat and has little to do with engine heat. On my 2016 Limited there is about 3 inches between the top of the muffler and the floor above and it gets fastened from the underside and not from above. A post above mentioned the cause of the condition, dissimilar metals interacting with each other. Thin aluminum attached with steel screws against a steel underbody. Where I could reattach the fallen shields I just used much larger fender washers but they too will rot soon enough. I am pretty sure these heat shields do serve a purpose but I would love to hear from a Toyota dealers mechanic about how the dealer might attack this issue. My bet is the dealer would just do as I did and yank them out or if they have a sucker on the line and could get new shields it would be a very hefty bill to drop the exhaust system and install the new ones. I seriously doubt, even with my Platinum warranty, this would be a covered repair but I don't know for sure. Just thought a few here might know.

I got the one on the driver’s side up by the engine rattling when off-roading. So f’n annoying. Looks very tight to get in there to address.

Yeah a mechanic would rip it out. You might want to talk to one of there properly educated engineers to explain fluids and thermodynamics to you. Especially with that fancy warranty.
Cooler exhaust fluid, yes gases are fluids, equals reduced air flow from the intake back and increased back pressure. Making your engine work harder and even distributing a/f ratio. Your cats lifespan will be greatly reduced then you'll really have a hard time compared to this little issue.