Exhaust Manifold On A 98 Corolla - Corolland: the Toyota Corolla Forums

My 98 Corolla LE has made a buzzing noise when going into 2-3rd gear for the past 5 years (engine compartment). Its VERY noticeable when it has rained and i'm driving, sounds like the car is farting. haha.

I'm almost certain its the exhaust mainfold (several trips to the dealer werne't helpful). It barely passed emissions inspection 2 years ago (I'm in CA), and I am almost certain it won't pass this year, as the sound has gotten slightly louder.

What kind of exhaust manifold should I buy, as I see there are a lot of aftermarket options and don't want some POS that will rust out. Second question, any ideas what this would cost to install??

I'm the original owner with 136k miles and I plan on running the car into the ground. default_biggrin

Thanks.

david

I doubt the exhaust manifold itself is cracked or has a hole in it - on our generation of Corolla, it is more likely that the exhaust donut between the flexpipe and exhaust manifold is burned up or cracked.

If you are set on getting an aftermarket header - avoid the eBay ones like the plague. I'd some more than 50%-60% that went with an eBay header (majority of those were OBX) immediately regretted it. Leaks, poor fitment, spotty welds, sometimes bent flanges - not worth the headache. DC Sports is a reputable one for the 8th gen Corolla. There are others - but are harder to find.

Another option, since you were considering swapping out the exhaust manifold, is to port the existing one. A few that have spent the time porting the OEM one actually had better gains than ones running aftermarket exhausts. Not only will you probably find/fix the leak (usually donut, exhaust manifold gasket in other cases) - but gain a little extra out of it and pocketing around $250-$350 for a new header.

I doubt the exhaust manifold itself is cracked or has a hole in it - on our generation of Corolla, it is more likely that the exhaust donut between the flexpipe and exhaust manifold is burned up or cracked.
If you are set on getting an aftermarket header - avoid the eBay ones like the plague. I'd some more than 50%-60% that went with an eBay header (majority of those were OBX) immediately regretted it. Leaks, poor fitment, spotty welds, sometimes bent flanges - not worth the headache. DC Sports is a reputable one for the 8th gen Corolla. There are others - but are harder to find.
Another option, since you were considering swapping out the exhaust manifold, is to port the existing one. A few that have spent the time porting the OEM one actually had better gains than ones running aftermarket exhausts. Not only will you probably find/fix the leak (usually donut, exhaust manifold gasket in other cases) - but gain a little extra out of it and pocketing around $250-$350 for a new header.

Sorry, what exactly does it mean by "port" the header or manifold? Where would I go to have that done? default_smile

I am looking at the diagram for the exhaust system (posted on here) and what exactly would need to be fixed? The Front Exhaust pipe. Where is the donut located on that layout?

K_Watson

My car also buzzes after running in heavy rain, or through a puddle. I suspect it's something to do with the intake.

Sorry, what exactly does it mean by "port" the header or manifold? Where would I go to have that done?
I am looking at the diagram for the exhaust system (posted on here) and what exactly would need to be fixed? The Front Exhaust pipe. Where is the donut located on that layout?

Porting is a process where a tech will grind and sand portions of the exhaust manifold to smooth transitions between joined pieces and to make everything inside more or less smooth. Same effect as taking sandpaper and smoothing any rough edges on a wood project. "Smoothing" the correct areas on the OEM exhaust manifold will enhance exhaust flow and speed, generally freeing up some power in the process. Not something that can be done by anyone - takes years of practice to get the right feel for it. A mix of engineering knowledge and artistic metal work - but there are some speed shops in many cities that probably have people that can do it.

Here is a link that might help - https://img.photobucket.com/albums/v620/fis...hgenexhaust.jpg

There are two exhaust donuts. One is right after the exhaust manifold, one is right infront of the catalytic converter. Usually the one right after the exhaust manifold gets chewed up over time. If you drive in a heavy rain or splash water up under the car and the engine sounds seems to change pitch or volume - then either you sucked some water into the airbox or more likely, you have an exhaust leak due to a bad donut.

My 2000 Toyota corolla is doing the same thing. I have 197,000 miles on the motor. 90,000 of them were put on in the past 8 months. When I first bought the car I could hear the noise slightly (it was bairly noticeable) wen dropping into 3rd gear for a corner at about 65 mph. But its been 90,000 hard... Really HARD miles and it was raining pretty good the other day and now I hear what sounds like water in my engine...... I ALSO SUSPECT IT IS AN AIR INTAKE PROBLEM! PLZ HELP

if the noise is much more noticeable after you run the car through a puddle or the roads are wet - definitely have the exhaust system's gaskets looked at. Especially on the downpipe, on these 8th gen Corollas/Prisms.

There is a spherical like gasket between the exhaust manifold and the downpipe - right by the upstream O2 sensor and the spring bolts. There is another one, flat spiral type gasket, on the downpipe leading to the resonator right after the catalytic converter, under a band clamp. Because that downpipe can wiggle around during operation, and usually occurs after a significant amount of miles and/or the engine/transaxle mounts are worn out - it can chew those gaskets up pretty quickly.

On my 2002 w/ ~ 255K - I'm on my second replacement set of gaskets - pretty cheap parts, just a PITA to replace without the right tools.