I just had this done to my 2003 V8. I must say it really, really quieted the car down. I guess I had gotten used to how noisy it had become. The car has 109k miles and I would say the crack started being heard a few thousand miles ago. The crack appeared on the bend of the manifold next to the #2 cylinder (i.e., passenger side, toward the front of the car). It was a big, visible crack. On startup the car sounded like something from a trailer park, but it never fully quieted down even in operation.
So I determined to replace the cracked manifold. I know that some people advocate putting in the Thorley headers so that there's no chance of having cracks again. I'm not sure I could have found a set of Thorley headers, but even if I could have my mechanic advised against it. The magical thing that I enjoy about the V8 4Runner is the insane amount of twist available at very low rpms. It just wuffles along like a Rolls Royce! My mechanic said that owing to the lower back pressure, the headers would probably move peak torque up the rpm band. So, overall performance might indeed improve, but it would probably be at higher rpms, which would have taken away the whole point.
Anyhow I bit the bullet and bought an OEM Toyota manifold, gasket and stud kit. The best price I could find was $539.28 for everything, from Toyota Parts Center (they often seem to have the best prices, and the shipping's free).
The mechanic charged me $373.73 to carry out the work. This seemed like a good deal since those old studs were completely rusted in place after 18 New England winters and it took him a huge amount of effort to get everything apart and reassembled. Surprisingly, he was able to get the old O2 sensor out and it works fine so we just re-used it.
At any rate, the truck is way, wayyyyyyyy quieter now.
So how much did all those parts cost? Everything squared away, ticking gone?
Just got this problem myself, hopefully I donÂ’t have to bend over too badly! Curious about whether warranty would still be available for sub-80k mile V8s...
