Exhaust Flex Pipe Question

[2000RX300]

A couple of years ago I went to a muffler shop with a leaking flex pipe. If I remember correctly, the original one had the steel woven mesh around it. They replaced it with one that is corrugated steel (not the mesh style). At the time, I was more concerned with talking them into replacing just the flex pipe and not telling me that I needed a complete pipe assembly so I did not ask them about the difference. Now it sounds like the flex pipe is leaking again. Does anyone know it the mesh style is just a covering over a corrugated pipe or is that mesh the actual pipe? The warrantee on the flex pipe has expired so if I am paying for a new one, I am thinking that I would try to find the mesh style if that is a better design. Due to the age of the vehicle, I was avoiding replacing the complete pipe because it bolts to the exhaust manifold. Call me chicken but those rusty manifold bolts make me nervous…

What do you folks think? (It’s for my 2000 Lexus RX300)

Thanks,

Bob

 

[Kestas]

The braided mesh is just a covering for the metal bellows underneath. It can stop rock damage, but unfortunately it traps corrodants and produces what is called poultice corrosion. It sounds like the shop replaced the original one with a cheaper version. This is one of the products I've studied for the auto companies in the past.

 

[HerrStig]

It's part of the price of transverse engine front wheel drive. The old Saab 900s with the engine mounted in the "conventional" way, (but backwards) didn't use one. Check RockAuto for prices on good quality pipes. If you don't live in California, but have a California spec car, you can often save on parts that fit perfectly but don't have the "approved for California (CARB) stamp.

 

[mechtech2]

Originally Posted By: Kestas
The braided mesh is just a covering for the metal bellows underneath. It can stop rock damage, but unfortunately it traps corrodants and produces what is called poultice corrosion. It sounds like the shop replaced the original one with a cheaper version. This is one of the products I've studied for the auto companies in the past.


This is correct.^
{Even though I don't understand how chicken wings [poultice] get in there!}

 

[AVB]

The mesh covered pipes can be expensive, are the motor mounts worn out? If the engine moves too much it can break the flex pipe.

 

[dwcopple]

Originally Posted By: HerrStig
The old Saab 900s with the engine mounted in the "conventional" way, (but backwards) didn't use one.
Chryslers too. At least the good 3.5L LHS's and 300M's that were FWD 1999-2004

 

[eljefino]

Saw a transverse cavalier 2.2 with just a spring loaded ball/socket gizmo with "packing" asbestos-y donut thing for flex. I was even more amazed when its 11-year old fasteners came loose easily!

You can get horrid quality universal flexpipe at the auto parts store, where you cut it to length and slap some clamps on it. This will leak from the get-go and won't pass inspection here. It's basically dryer vent! I like the braided stuff; I get at least a few years out of it and the ones I've bought (advance auto; $30) have been stainless.

Replaced nasty with good.

 

[2000RX300]

Originally Posted By: AVB
The mesh covered pipes can be expensive, are the motor mounts worn out? If the engine moves too much it can break the flex pipe.


Good Question. I was wondering about that myself. Anyone know a easy way to check the motor mounts?

 

[AVB]

If you lift the hood, can you see the engine from the drivers seat? If not you will need a helper. Start the car, hold the brakes and shift to drive. Watch the engine to see if it kind of flops back. Do the same thing with reverse. If the engine flops back and forth then you have some bad mounts. They can still be bad even if it doesn't, but if it does flop you definately have at least one bad mount.

 

[mechtech2]

Originally Posted By: AVB
If you lift the hood, can you see the engine from the drivers seat? If not you will need a helper. Start the car, hold the brakes and shift to drive. Watch the engine to see if it kind of flops back. Do the same thing with reverse. If the engine flops back and forth then you have some bad mounts. They can still be bad even if it doesn't, but if it does flop you definately have at least one bad mount.


This works if the mounts are really bad. With an auto trans, put it in drive or reverse, and goose the throttle a little [brakes applied hard]. Movement will be pronounced and jerky.
Some movement is normal.