Heya. A Honda tech told my I have a cracked header that needs replacement. It was mentioned that the header may be able to be welded instead of replaced. I have read online that you can check for a header leak by placing your hand over the exhaust pipe and seeing if the car still runs. I placed my hand over it for about five seconds until the pressure was so great it popped my hand off like a loud cork. Could this mean my header is fine, or is that a bad way to test it?

Edit: I also thought I'd mention, this thing's gas mileage really sucks. I get about 20mpg. I did a little test though... I took a road trip, about 600 miles total of straight freeway driving. I got between 37-42mpg, so it seems like my economy problem is related to acceleration... this thing is totally gutless. FYI, I've done all the standard tune-up procedures, and have made sure it's in time. Could this mpg problem be caused by a cracked header?

 

WHAT...???? Please clarify.. put your hand where..???

When pepz said put hand over exhaust, meaning put it near the area that you suspect where the crack is and you can feel the exhaust air coming out.. Not literally put hand on it..

 

The advice was to place the hand over the exhaust pipe on the backside of the car where it comes out of the muffler. I believe the theory is that if you cover the exhaust pipe, and a hole in the header exists, it'll force the air out of the hole, allowing the engine to continue running. I believe I read this on a different forum. I'm just curious if this is a valid way to test for a header leak. If not, I'll trust that the leak is indeed there, and figure out a way to either have the header welded or maybe replaced...

 

WTF..?? Stay away from that forum advice, but you just made my day ROFLMAO

Stuff a rag on the end, don't put your hand on it.. LOL

 

Heehee, glad I provided some laughs. It actually hurt my hand when it shot it off, lol. Anyways, I will stuff a rag in it. I'm guessing if it stalls the car, the header is ok, and if it keeps running, there's a leak... is that right?

As a side note, I definitely smell exhaust in the engine compartment and occassionally in the cabin of the car. And as mentioned earlier, sluggish accelleration and low mpg.

Thanks for your input, btw.

 

It will not shut the car off if the hole in the exhaust pipe is blocked..... you know... like it should be. Stuffing something will not do anything except for creating a possible mess.

It is common to see the y7 exhaust manifolds crack in between runners. Some weld them shut, and it works, some are not so lucky.

Are you getting a CEL from it? O2 sensor CELs I would presume if anything.

You are getting less gas mileage since the exhaust gases are escaping from the manifold and not allowing the o2 sensors to read the air/fuel mixture properly causing the excess gas to be wasted.

You can try to have it welded, and hope it works. Otherwise, replace it and move along. If you replace it yourself, buy a set of extractor sockets in addition to replacement bolts since it is likely you will break or strip every 14-or-so-year-old bolt that is on the exhaust system (common). It took me about 2 hours to replace my brother's cracked y7 manifold.

 

Have someone else block the tailpipe while you are under the hood to listen for a hissing sound from the header or wherever the crack may be. If pressure builds up quietly, there is no leak. It isn't necessary to wait until the engine may stall.

 

cvcrcr99, thanks for the reply. I'm not having a CEL. I have not visually inspected the header yet, but will try to take a peak while doing my t-belt this weekend. As an aside, if a weld doesn't work, and one does not want to shell out $500 for an OEM replacement, what is the best route? I keep reading about aftermarket header + cats causing issues due to the length of the O2 sensor wire.

 

Alright, so I jammed a rag into the tailpipe and started it up and let'r run for a minute or two. I heard no discernible difference in the header area between the time the rag was in and out. I did notice that when the rag was in, a small amount of water pooled below the area where the muffler connects with the pipe below the car. Could this be problematic?

As an aside, thanks for all the help you guys provide. I was able to do my t-belt, water pump, cam and crank seals thanks to the help here.

 

That is just water draining out of the drain hole in the muffler. You could remove the header heat shield for a visual inspection.