Questions about Exhaust systems, Catalytic Converters and Headers/Manifolds

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15
votes
8answers
43k views

What is the best way to remove a stuck/rusted exhaust bolt?

I'm trying to disassemble the exhaust system on a 2000-2003 nissan maxima and I'm having trouble removing one last bolt.. its got a 14mm head and its just plain STUCK. I've tried soaking it overnight ...
13
votes
3answers
46k views

What does a water-like drop coming out of the exhaust of the car signify?

Sometimes while driving in the traffic, I come across a car or two which would be dripping water-like drop from it's exhaust steadily in a break of 4-5 seconds. I tried to ask a couple of people at ...
11
votes
3answers
7k views

When car is standing still, I smell Diesel exhaust. Why?

In my 2003 Opel Vectra, the cabin air smells of Diesel exhaust while stopped at e.g. a red light. The exhaust smell goes away when driving, and it also doesn't come back if I turn the ventilation off ...
9
votes
1answer
5k views

Is this what is making my car sound like a racecar?

Recently, my car (2000 Mercury Grand Marquis) started sounding like a racecar: the engine became very loud. There's clearly something going wrong with the exhaust system. I'm trying to understand ...
8
votes
3answers
3k views

Catalysator broken? Odd rope coming out of the exhaust pipe

[UPDATE] SOLVED! Hurray! The muffler had corroded inside and it blocked the exhaust system, making bad to motor. I got it fixed and the car energy efficiency improved from 12-15 liters/100km to ...
7
votes
1answer
4k views

What are the tell tale signs of a catalytic converter that might be going bad?

I've owned two vehicles whose catalytic converters were recalled due two a couple of reasons: one being the quality of the CC and the other being a reduction in power due to a material building up and ...
6
votes
3answers
4k views

How effective are exhaust patch kits?

How effective are exhaust patch kits in terms of longevity and limiting noise and leakage? Specifically I'm looking at using the kind that consist of heat-activated tape, an aluminium sheet and two ...
6
votes
2answers
5k views

Muffler off car. Safe to drive with exhaust open underneath?

So leaving work yesterday I heard a clang! - the muffler simply fell off. Further inspection revealed a lot of rust in one particular area on the pipe. Thankfully the forward muffler is still intact ...
6
votes
4answers
45k views

Sputtering while driving & idling

[My car: 2004 Mazda 3] So, my wife came home from running some errands and told me the check-engine light was on and that the car was sputtering and felt like it was going to stall while stopped at ...
5
votes
2answers
4k views

should I replace gaskets when replacing exhaust?

I need to replace a broken section of exhaust. Should I replace the gaskets also? one of the gaskets is directly between the engine and the new part. The other is between the new and an old part of ...
5
votes
2answers
314 views

Performance Exhaust — what, how, why?

I've seen performance exhaust pipes on sale for cars and motorcycles, and my questions are these: What does it do? (better performance [and how so?]? better mileage? cooler sounds?) Is/how is it ...
5
votes
1answer
2k views

Does it make the most sense to replace an old car's entire exhaust system all at once?

Back story: The Check Engine light came on in my 2005 Chevrolet Malibu LS Sedan (V6 3.5L). I took the car to a mechanic #1 (M1), an independent shop. They replaced the EGR valve. A day later, the ...
5
votes
1answer
63 views

Car feels like it's filling up with fumes

I bought a used 2000 volvo s80 with around 93k on the odometer. I was driving the other day and I felt sort of sick. At first I thought it was some dirt on the floor that got into the air. But upon ...
5
votes
1answer
56 views

Rust underneath rear of car (Toyota Mk1 MR2)

I have recently acquired an old (1989) Mk1 Toyota MR2 and took a few photos of the underside rear of the vehicle. There seems to be a fair amount of rusting on the rear axle and gear box: gear ...
4
votes
3answers
2k views

What does it take for a modern muscle car to sound like a classic muscle car?

To preface, I would grade my exhaust knowledge with a "B-". I know what the major components are and what they do, but I don't know if and when certain exhaust parts became mandated or introduced ...
4
votes
1answer
64 views

Exhaust on a replaced motor

I recently had to change the motor in my 2004 Hyundai Sonata. I bought a used one from the junkyard, and it fired right up after I got it put in, and all the wires, hoses, etc. connected. The only ...
4
votes
5answers
2k views

Remove rounded manifold bolt

I'm trying to take off the manifold bolts on an old Chevy 350 (the ones that connect the manifold to the header). I got 4 out of the 6 bolts out, but 2 are extremely struck and rounded due to all the ...
4
votes
1answer
2k views

Car Stalls When Coming to a Stop

Make: Chevy Model: Cavalier (4 cyl.) Automatic Year: 1993 Miles: 230K Normally my Cavalier drives just fine without problems. However, if I drive for 45+ minutes then it will sputter and stall out ...
4
votes
1answer
239 views

Motorcycles: Way to maintain shiny chrome on exhaust outlets?

I have a motorcycle that has chromed exhaust pipes. I am worried that there will eventually be discolouration where the pipes join the engine, due to the heat. Is there a way to treat the pipes so ...
4
votes
1answer
463 views

Biodiesel and DPF (Diesel Particulate Filter)

I read a little about DPFs and biodiesel. Some claim that there's a reduction in lubricity and/or viscosity of engine oil when using B30 or above. They warn about increased engine wear because of it. ...
4
votes
1answer
289 views

Options for replacing rusted exhaust mounting bolts

The car is a 2005 Mini Cooper. The bolts that hold the exhaust mounts in place have rusted and snapped on both sides: I've taken up the floor of the boot and have located their heads on either ...
3
votes
3answers
38k views

Why am I smelling exhaust inside the cabin of my car?

When I drive my car the first few miles, I smell exhaust inside the car with the windows rolled up. It happens when I have either the AC or the heat/air on... What's going on?
3
votes
2answers
77 views

Repairing a thin cut in exhaust pipe

I am looking for a way to repair a small hole I created in my exhaust. The hole is about 1 to 1.5 inches long and only about the width of a cutting wheel (you can guess how the hole got there). I ...
3
votes
3answers
240 views

How much of the exhaust is the “cat-back”

My brother-in-law's car has just failed inspection. One of the items listed was a "cat-back." Since the bill is astronomical, I was wondering how much of the exhaust system is encompassed in this term ...
3
votes
2answers
349 views

Single Cylinder 2 stroke bike with twin exhaust, will it need two chambered exhausts?

I am asking specifically about Yezdi (not in production anymore) 250/350cc motorcycles. Yezdi RoadKing was a 250cc single cylinder two stroke with twin exhaust. If upgrading to a calculated chambered ...
3
votes
1answer
156 views

Exhaust smell emanating from old car?

I drive an '97 Subaru Legacy. Far as I know, it still works perfectly. Lately, there's been a bad exhaust smell around the car when I park and get out. I can smell it inside the car on occasion, but ...
3
votes
1answer
477 views

White smoke from tail pipe on operating temp start

I have a 89 Buick Century Custom. On the first start of the day, I have no problem. No smoke and no difficulty starting. However, after the car warms up, say, after driving to a gas station the ...
3
votes
1answer
1k views

Can header / exhaust insulation replace metal heat shields?

Following up on my saga: What could be causing a distinct exhaust drone in a tight band around 3250 rpms on a 2004 Subaru WRX? At the end of that quest, we concluded that the right hand exhaust ...
3
votes
1answer
1k views

Is it possible to use biodiesel in a BMW 335d if I remove the DPF and remap the ECU?

The new (2009-current) BMW 335d sells in the U.S. with a DPF to reduce emissions, but which prevents the use of biodiesel. I've read about people removing the DPF and re-mapping their ECU to get ...
3
votes
1answer
48 views

How long will my motor last having clogged catalytic converters?

My catalytic converters have been clogged for awhile, and the o2 sensors need changed because of this. What is it doing to my engine? And gas mileage for that matter? If i take out my ...
3
votes
1answer
2k views

2000 VW Golf TDi (Mk. 4) grey smoke from exhaust before engine has warmed up

I have had my Golf for 8 years. It’s had good maintenance and a the record is kept by my dad. It’s just passed its MOT (Ministry of Transportation) test, and the mechanic mentioned that the tappets ...
3
votes
2answers
715 views

VW Golf 2.0 SDI (2005) - smokey when pulling away

Over the last 12 months I have noticed that as I pull away and put my foot down a little more, there is often a bit more of a cloud of smoke left behind. Its not thick smoke but still it seems like ...
3
votes
1answer
44 views

Lost torque on my Yamaha XVS650

I have a Yamaha DragStar 650 1999. I have a Highway Hawk exhaust and I removed the baffles. Now the exhaust is completely open. When the engine is cold I can start it only if I pull the acceleration ...
3
votes
1answer
91 views

Is it normal to attach a catalytic converter with U-bolts?

I need to replace my catalytic converter. The current one is held in place by U-bolts. Two U-bolts between the cat and the manifold exhaust pipe (looks like a patch). One holding the exhaust pipe to ...
3
votes
2answers
328 views

MINI Cooper Oil Leak

I bought a 2007 MINI Cooper 8/27/14. On 9/9, as I drove to work, I noticed smoke coming from the back & front of the car. When I drove home late that night, the car was not smoking. After that ...
3
votes
2answers
5k views

Mass Air Flow Expected Values

I have a 2002 Audi A4 Quattro 3.0. I have a Vagcom USB cable and I am trying to diagnose the MAF sensor. I had a friend get some readings from an OBD2 scanner, which indicated that both precat O2 ...
3
votes
1answer
854 views

Mechanic Troubles And A Small Watery Oil Leak

My car is a 2005 BMW 525i E60 with about 180,000km on the clock. It has been well looked after and serviced. I don't get dealer services, but go to a mechanic who has always been good and uses the ...
3
votes
1answer
288 views

muffler positioning, and x-flow for specific sound

I am re-designing a ferrari exhaust system with 2 objectives: 1: enhance the specific high pitch raspy sound that you expect from a small ferrari V8. 2: achieve a good free-flow design. There is ...
2
votes
3answers
4k views

Blue-ish smoke coming out from the exhaust

I have a VW Golf mk4, 1.9 TDI from 2001 with 230.000+ km on board and for some time now I have blue smoke coming out of the exhaust. The problem aggravates when I'm stuck in traffic or when the ...
2
votes
3answers
9k views

Rattle on Ford Focus, suspect heat shield

Ford Focus 1.8 Ghia '99 V A little while ago a large section of the aluminium heat shield above my exhaust came loose. Being in a situation where I needed to keep going and without tools, I crawled ...
2
votes
1answer
31 views

Rusty exhaust manifolds

Most of the engine on my 2007 V6 Tacoma is in a really good shape but both exhaust manifolds coming out of the engine block are really rusty. Q1: Is that a reason to worry or replace them, provided ...
2
votes
2answers
3k views

Failed emissions - high lambda, low HC and CO

My 2007 Daihatsu has failed the national car test on emissions. The readings at 3500rpm are: Lambda: 1.10 (normal range 0.97 - 1.03) CO: 0.02% volume (normal range below 0.20%) HC: 11ppm (normal ...
2
votes
1answer
47 views

Emissions codes after oil through exhaust

I have a 2003 Subaru Legacy L with the EJ251. I rebuilt the engine because of a thrown rod. There was significant damage to the shortblock, which resulted in a significant amount of oil escaping the ...
2
votes
1answer
658 views

Changing the exhaust on a motorbike

I have a Yamaha XJ6 from 2012 and I would like to change the exhaust. But I have a choice. Do I change only the muffler or the whole "line"? Other than cost what are the pros and cons of changing ...
2
votes
1answer
691 views

2003 Honda Civic 1.7 vTec - White Smoke from the tailpipe

I have a Honda Civic 2003 gx 1.7 liter vTec stick shift 4 cylinder. Just today I had to put oil in my car. Drove for about 5 minutes got to a light and when I shifted into first gear a white cloud of ...
2
votes
2answers
703 views

Grey smoke when idling 1999 GMC Suburban, coolant system pressure loss

The most recent update is at the bottom. This looks interesting. The Smoke I'm confident the smoke is from burning oil. It's slightly blue, absolutely not white. If the engine is warm and I am ...
2
votes
1answer
841 views

What causes the “pop” and “burble” noises on overrun?

I love the sound, just wondering what causes it.
2
votes
1answer
145 views

How should I diagnose an exhaust “howl” when descending through 3200 rpms?

As mentioned previously, I have a 2004 WRX wagon with a stainless Prodrive circular-tip axle back installed around 2006. Lately, the weather has been nice enough to drive with the windows open and ...
2
votes
2answers
220 views

Is there a good online resource for exhaust system design? (theory)

I am looking for information on the effects of changing certain criteria in an exhaust system relating to its performance and its sound. I am unable to find any resourses relating to this on the net ...
2
votes
1answer
515 views

'04 Nissan Sentra - Smoke from engine compartment after long drive

My sister has a 2004 Nissan Sentra with a 1.8L engine, and a day or two ago she started noticing some (not a lot) smoke coming from the engine compartment after driving for a long time (i.e., more ...