Exhuast Manifold

I have a 99 Toyota Tacoma. I bought it about 2 years ago. When I purchased it I had a cracked exhaust manifold that I had replaced with a new one in October of '08 since then the new one has cracked (I am estimating this happend about 4 or 5 months ago) Does anyone know what might be causing this to repetitively happen?

 

Which motor? 3.4L, 2.7L or 2.4L?

 

2.7l

 

Here are links to a couple of threads that have covered some of this ground before.

http://www.tacomaworld.com/forum/1st-gen-tacomas/67188-manifold-cracked.html


http://www.tacomaworld.com/forum/1st-gen-tacomas/57091-exhaust.html

 

Im interested in this as well. I just replaced mine, 117.00 from O'reillys. When I pull the old one it had a crack all the way around, I intentionally dropped it from about 3 feet, and it split in two, there was only about 30mm where it was attached prior to the drop. Only about 30mm didnt have rust on it, in the process (before installing the new EM I blew both O2 sensors, bank 1 sensor 1 and bank 1 sensor 2, quite an expensive fix. Its working like a champ now (crossing fingers) and all engine lights are off. good luck!

 

Where is it cracking? Your exhaust flange may not be truly flat, which may put strain on the manifold. Then when it heats and cools it expands and contracts. Then it gets weak and cracks.

 

Very common for the 2.7 engine. Mine was cracked really bad when I bought my truck. So bad that you could smell exhaust when the heater was on.

I would recommend buying a set of headers (solid steel tubing=stronger and less prone to cracking). Stay away from Pacesetter, though. I've heard bad things about them and you get what you pay for. I got a set of ceramic Doug Thorley Tri-Y headers from TRDparts4u.com for under $400.

 

I have been talking with a few local mechanics regarding my situation. I was able to get my Dorman Manifold replaced through lifetime warranty but will have to pay someone to do the labor again. The mechanic I am working with told me that Tacoma's are known for this happening as well as Jeep Wranglers. "It's like a design flaw" He also told me it could be the manifold itself, and I could have gotten a bad one. Any thoughts on this?.........