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Exhaust Manifold


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Hello NPORA!

 

I recently picked up a 1994 Pathfinder v6 with an awful exhaust leak at the manifold on the passenger side. I pulled off the heat shield to find the stud closest to the firewall missing. After trying to thread in a new bolt it is also obvious that the threads have been pulled out of the head too. Running the Pathfinder is quite loud, and I have confirmed from feeling around with the engine running that the leak is where this stud is missing. 

 

So onto my question: Is it ok to continue to drive like this? I understand it is not ideal, and the noise bothers me, but I just bought the Pathfinder and was hoping to be able to enjoy it a little. Also not really looking forward to retapping threads in a tight clearance area, as well as probably breaking more studs trying to remove the manifold. But will driving it end up burning an exhaust valve, or causing any other damage? The previous owner drove it around like this for many years it sounds like, and the truck doesn't have any running symptoms that would indicate a burnt valve at this point. 

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I drove like this for some years (as well as the PO for some years) and never had an issue.

I eventually got tired of the noise and had someone fix it out in the country (cheaper than the city and they're used to patching things back together).

 

My guess as to what could possibly happen if it's not fixed is more studs could break, possibly fail an inspection (if you have them) and the O2 sensor readings not being 100% correct so the car does not run optimally. Also, depending on where the escaping heat is directed, could ignite the jute padding on the other side of the firewall but that probably would have already happened at this point.

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:welcome:

 

I've been ignoring the same problem for years. Busted stud, same as yours (same one too, I think). It's dead common on these. The studs were too small or the wrong steel or something. The next version of the engine (the VG33) uses larger studs, not that this helps you any.

 

My dad had the same problem on one probably twenty years ago, and had a shop cut an access hole in the inner fender to make it easier. I bought a 90* drill adapter to try and do mine without cutting sheet metal, got some 300ZX exhaust studs (IIRC they're supposed to be stronger?) and new manifold gaskets, and then never got around to it because it looked like a PITA and it wasn't obviously hurting anything.

 

I don't think I've ever heard of one of these burning an exhaust valve.

 

There's also a common exhaust leak at the Y-pipe, under the driver's floor. Tends to rot out the floor under the driver's right heel. That one will set your carpet on fire if it gets bad enough.

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  • 3 weeks later...
On 5/25/2024 at 4:01 PM, Slartibartfast said:

That one will set your carpet on fire if it gets bad enough.

Thanks for triggering my PTSD over this even though it was nearly a decade ago.

  • Haha 1
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