a sweet truck nevertheless

April 21, 2010 7:12 PM

Can I wait a couple of weeks to fix my exhaust system?

I'm driving a 1986.5 Nissan hardbody with an epic 230k on it, which I just bought a few weeks ago. I had associated the growl with what i understand is a small common flaw -- the vestigal vacuum tube hole in the catalytic converter -- which I planned to take care of some time in the near future, once I've gotten a few paychecks from the job that I needed the truck for.

Today, however, I realized that the exhaust pipe before the muffler has corroded and cracked all the way through so that the muffler and exhaust pipe are literally hanging by a thread. Not such a big deal to replace the exhaust system, I realize, but I don't have the cash on hand yet. I don't mind the growl, and even don't mind a loss of power or efficiency for a few weeks, but I don't want to keep driving it if I'm risking doing serious damage to the truck.

Important -- I drive between 150-250 miles a week for work.

posted by milkman to Travel & Transportation (14 answers total)

As long as the exhaust manifold (the much more substantial thing that takes the exhaust out of the cylinders, down the side of the engine, and to the exhaust pipe) is still in one piece and connected to the block, you should be fine.
posted by M.C. Lo-Carb! at 7:24 PM on April 21, 2010

You probably get a bit more power, as mufflers restrict the airflow, and you are now successfully bypassing it! Agreeing with M.C. Lo-Carb!
posted by defcom1 at 7:38 PM on April 21, 2010

You'll be fine but you want to make sure that if the two pieces separate that they'll remain with the truck rather than hanging down where they will get ripped off and possibly damage the body or brake lines. Just about any kind of uncoated wire will do the job short term to tie the pieces to the truck.

If the pipe hasn't broken off flush with the muffler a band clamp will keep things together (you don't need stainless ones obviously) and are cheap.
posted by Mitheral at 7:43 PM on April 21, 2010

You won't do any damage to the truck, but you do risk getting pulled over and ticketed either for noise or for missing required equipment. Throw some muffler tape on it to quiet it down until you can do the real repair. A break that far back shouldn't effect your engine performance at all, btw.

(currently driving around with no muffler at all, hopefully only until Friday)
posted by bizwank at 7:45 PM on April 21, 2010

If it's hanging by a thread, it's a serious hazard to both the back end of your car and other drivers. What if it breaks off on a crowded freeway? You should fix or get this fixed right away. The good news it's a relatively cheap repair.
posted by Camofrog at 8:06 PM on April 21, 2010

Best answer: 300 feet of 18-gauge hanger wire is available at Home Depot for about $7.50. I suggest that you buy some and then get under your truck to make sure that rear portion of your exhaust is not going to fall and make your truck do a bit of a pole vault while doing 30. Besides the danger, I can personally attest that it's scary as hell (at least in an '83 VW Rabbit).

I would also take bizwank's suggestion and try to mend the leak with muffler tape. If I felt good about my work with the wire, I might even mend the leak with a soda can and some JB Weld and not worry about it until I needed a sticker, but I'm classy like that.
posted by Mayor Curley at 8:14 PM on April 21, 2010

A contrary opinion: If the vehicle has electronic fuel injection (EFI), you run the risk of the oxygen sensor (O2 sensor) not reading the proper air/fuel ratio. The O2 sensor measures the amount of oxygen that is present in your exhaust gases. On your vehicle it is the primary sensor the engine uses to maintain a ratio of 14.7:1 for best mileage during part throttle cruising (i.e., most driving around). If the exhaust leaks before the sensor can measure it, the EFI computer won't get the right reading and will try to compensate -- in this case, there would not be enough oxygen, so the computer would think the engine was running rich (that there was too much fuel in the mix of air/fuel) and would remove fuel, making the motor actually run lean (not enough fuel). Lean running can cause all sorts of problems, but the most significant is that it will raise temps in the cylinder, which can lead to burnt valves and a ruined catalytic converter. It also raises the risk of detonation, which will cause your motor to damage itself.

My advice would be to get this dealt with as soon as you can afford to. You sound like you are on a tight budget, but this is the sort of small problem that can lead to a huge problem if it is left unattended. 150-200 miles per week is enough mileage to worry about this doing just that.
posted by mosk at 8:53 PM on April 21, 2010

One of your fellow Mefites (and human beings) could easily have been killed by a muffler that fell off a car in front of him. Fix it tomorrow.

This. (Emphasis added.)
posted by three blind mice at 1:31 AM on April 22, 2010

Are there any rust-through points (visible or not) in this old vehicle, that would allow exhaust to enter the passenger compartment ? That would be my main concern.
posted by Kevin S at 5:11 AM on April 22, 2010

You can avoid it falling off by getting under there with tin snips and hacking it off. Then you can forget about it indefinitely.
posted by Meatbomb at 6:52 AM on April 22, 2010

For all the jokes Mayor Curley spews about Mainers and their Coffee Brandy and backwardness, his advice is about as Maine as it gets.. nevertheless, I 2nd his suggestion.
posted by mbatch at 7:52 AM on April 22, 2010

Nissan made this trucks forever (the hardbody line i think), should be a lot in junkyards, so go and look around, you can probably find one that has a exhaust system in better shape than the one you are driving. It doesn't have to be perfect, just good enough to limp along until you can fix it right. However there are some long term things to think about running a car without a sound exhaust system:

1. without a functioning catylictic converter you are producing way more harmful emissions so there is the good citized angle

2. without adequate backpressure (the pressure in the exhuast system caused by the constrictions of the cat and muffler) can cause some engine problems like burned valves and rough running from lack of functioning o2 sensor.

3. if that crap falls off and causes and accident you are liable and culpable. at least make sure it is secured to the vehicle

4. its loud and annoying without a functioning muffler, good citized angle here also

5. the exhaust system prevents toxic gases from entering the cabin and KILLING YOU.

so anyway, check out a junk yard, you can probably piece something together. this is all bolt on stuff that is probably the easiest system to fix on the whole car. I got a whole new exhaust system with muffler from the cat back on a civic for about $120 at a muffler shop, a wrangler setting in my garage currently has this issue and will cost about the same to fix so we are not talking a huge amount of money.
posted by bartonlong at 10:35 AM on April 22, 2010

citized should be citizen, stupid keyboard
posted by bartonlong at 10:36 AM on April 22, 2010

Response by poster: a soda can, some jb weld, and some muffler tape has resecured the pipe and quieted down the ride considerably. as soon as I get a paycheck that isn't already earmarked for backrent, I'll have someone help me replace the cat.

thanks everyone for the sound advice.
posted by milkman at 6:37 PM on April 22, 2010