Could head gasket repair cause damage to exhaust pipe?

subaru
imprezaoutbacksport

#1

I own a '05 Subaru Impreza Outback Sport. In February '16 I had the head gaskets replaced by my local Subaru Dealership. When the car was returned to me, it was noticeably louder. When I asked about it, they said something about there being more power in the engine with new head gaskets. I know nothing about cars so I leave. A few days later I notice a rattling under the rear passenger side of the car when I rolled over a bump and hear it regularly still. I ask about it every time I take the car in for an oil change. They can never find anything wrong and they can never seem to make my car make the rattling noise.

Today I took my car to another Subaru mechanic. They say they my head gaskets are still leaking and there is a crack in my exhaust pipe. Obviously, I’m going to take the car back to the dealership to fix the head gaskets, but is it also possible that they somehow damaged my exhaust pipe during the first repair? It’s hard for me to believe that these are not related because my car was so much louder when I picked it up from the initial repair. But then again, the problems are at two different ends of my car.

Thoughts?


#2

This is largely informed speculation… but you should have called BS when the first dealer said the engine was making more power with the “new” head gaskets.

I’ve never seen under the hood of a Subaru, though I know they are a different animal than your typical car. Did they have to remove/loosen an exhaust manifold to get to the head gasket? I wonder if that wasn’t re-installed properly and/or it was damaged. That would explain the louder exhaust sound.

If it were my car, I’d have it back at the first dealer tomorrow morning demanding an explanation. Good luck.


#3

No kidding. That’s an impressive level of lying.

And yes, the exhaust headers come off when you change the head gaskets because if you do it right, you pull the head completely and send it off to a machine shop for milling. Clumsy exhaust header removal can damage exhausts, and any shop which is so full of crap as to think it’s ok to tell people that a head gasket replacement is a performance modification probably has just as tenuous a relationship with good work ethic as it does with honesty.


#4

Depends on where the crack is. They do disconnect the exhaust manifolds from the heads, but if they can get the heads out without further removal of the exhaust system, they will just let it hang there.

Most of the time, there isn’t enough stress to do any damage, but if the exhaust pipe is rusted and about ready to go, then the strain could crack it, but it was going to crack soon anyway. Considering the age of your vehicle, it would probably have cracked sooner than later.

But that was some creative bovine scatology spewed out by the service rep at the dealer.


#5

I would see if the second subaru dealer would fix the head gaskets under warranty since it was done at a subaru dealership. Sure you will probably pay for the pipe either way, but I would try and avoid number 1


#6

Replacing the head gasket usually involves completely removing the head from the engine. The cylinder “head” is sort of like the grand central station of an engine, as incoming fuel and air from the intake manifold go through it one direction, and the exhaust gas goes though it in the other direction, escaping to the exhaust manifold, cat, and out the tailpipe. So all that stuff, the intake manifold, the exhaust manifold, etc, it is all manipulated as part of the job. With 12 year old parts, pretty much anything in those areas could be damaged in the process.

So it’s not unusual to end up with an exhaust leak. But it is pretty unusual to discover the head gasket is still leaking. Suggest to focus more on why that happened. If you can discover that, the cause of the other problems might be painfully obvious.


#7

I would suggest to contact that first dealership ASAP

Many shops warranty their parts and labor for one year . . . so that will soon be over


#8

I have an appointment with the dealership that did the head gasket repair on Friday. Thank you all for your insights. I will use the information you gave me to steer the conversation and you better believe I won’t be afraid to call BS this time.

Many thanks!