Exhaust Manifold leak

merduex · 04-07-2009, 07:50 AM

I'm planning to buy a MKI that has about 277k on the chassis and 40k on a rebuilt engine. body is straight, everything works fine, clean title, fairly cheap ($950) and haves an exhaust manifold leak. im not a mechanic nor do i know a lot about cars but how bad exactly is a exhaust manifold leak? how much would it cost to repair the damage or simply replace it? or if i choose not to fix the problem and let it persist. would it cause much harm to the car? whats the worse that can happen? overall, good or bad deal?

328FTW · 04-07-2009, 08:28 AM

That is not a huge problem at all. The exhaust manifold is the part the comes off the back of the cylinder head on the side of the engine facing the front of the car in this case that exhausts (coincidentally) the gases from your engine and connects to the muffler system. The manifold is probably crack on number four which is in America the drivers side (Left hand) part of the manifold. You can have it welded but it is normally easier to but a new set of extractors or a used manifold off another mr2 or a corolla (any fwd 4age car will do, the mr2 has a fwd setup in the back). It shouldn't cost much as it is an easy job. It won't harm your engine it is just annoying and means exhaust gases can possibly circulate into the cabin but it is just annoying more than anything.

mr3 · 04-07-2009, 08:34 AM

Often times the manifold on the #4 piston is cracked. I bought my car with a buggered up weld job on the manifold that didn't hold at all. It sounded like a something humming in my ear because it was right behind my seat. After a year I got one that was welded a bit nicer. Sounded so good. The car was silent at all speeds. 3 days later it cracked. My dad took the original one off and took it to his job. He works at a steel plant and had someone weld it up really nicely. Unfortunatly, the heat on #4 warped the mounting flange and now the leak is from there. It's still much quieter than before but it could be quieter. Even with 2 gaskets (an old v8 trick) it leaks. He's going to take the other cracked on in and get that rewelded but he'll bolt it down to something so it doesnt warp. Best bet is to find one that isnt cracked. The manifold gasket is about $20 tops and there are 3 bolts and 2 nuts holding the manifold on plus the egr bung. Then take the old gasket out and put a new one in and reinstall the manifold. I found it good to heat the engine up a little bit after the new gasket and tighten the nuts and bolts a little bit more. Hope this helps.

3dogsdad · 04-08-2009, 12:21 PM

My 1986 had the same problem. In Texas, we need emmissions test for licensing. Mine failed with 2000ppm. Mechanic said the leak in manifold caused the 02 sensor to send too much gas, and created the ppm issue. Got an estimate from mechanic for about $400.00. I found the part on e-bay or possibly Rockauto (good source), and replaced it myself. Ii is fairly simple, once you get room under the car. Do it yourself and save.
3dogsdad

04-07-2009, 07:50 AM	#1 (permalink)
merduex No Skills Join Date: Apr 2009 Posts: 2 Thanks: 2 Thanked 0 Times in 0 Posts iTrader Rating: (0/0% )	Exhaust Manifold leak I'm planning to buy a MKI that has about 277k on the chassis and 40k on a rebuilt engine. body is straight, everything works fine, clean title, fairly cheap ($950) and haves an exhaust manifold leak. im not a mechanic nor do i know a lot about cars but how bad exactly is a exhaust manifold leak? how much would it cost to repair the damage or simply replace it? or if i choose not to fix the problem and let it persist. would it cause much harm to the car? whats the worse that can happen? overall, good or bad deal?

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04-07-2009, 08:28 AM	#2 (permalink)
328FTW 3vzfe tinkering Join Date: Aug 2008 Location: New Zealand Posts: 1,531 Thanks: 12 Thanked 99 Times in 83 Posts My Google Map iTrader Rating: (0/0% )	That is not a huge problem at all. The exhaust manifold is the part the comes off the back of the cylinder head on the side of the engine facing the front of the car in this case that exhausts (coincidentally) the gases from your engine and connects to the muffler system. The manifold is probably crack on number four which is in America the drivers side (Left hand) part of the manifold. You can have it welded but it is normally easier to but a new set of extractors or a used manifold off another mr2 or a corolla (any fwd 4age car will do, the mr2 has a fwd setup in the back). It shouldn't cost much as it is an easy job. It won't harm your engine it is just annoying and means exhaust gases can possibly circulate into the cabin but it is just annoying more than anything.

04-07-2009, 08:34 AM	#3 (permalink)
mr3 Cage Fighter Join Date: Jun 2008 Location: Plymouth Mtg, Pa Posts: 844 Thanks: 19 Thanked 26 Times in 25 Posts iTrader Rating: (2/100% )	Often times the manifold on the #4 piston is cracked. I bought my car with a buggered up weld job on the manifold that didn't hold at all. It sounded like a something humming in my ear because it was right behind my seat. After a year I got one that was welded a bit nicer. Sounded so good. The car was silent at all speeds. 3 days later it cracked. My dad took the original one off and took it to his job. He works at a steel plant and had someone weld it up really nicely. Unfortunatly, the heat on #4 warped the mounting flange and now the leak is from there. It's still much quieter than before but it could be quieter. Even with 2 gaskets (an old v8 trick) it leaks. He's going to take the other cracked on in and get that rewelded but he'll bolt it down to something so it doesnt warp. Best bet is to find one that isnt cracked. The manifold gasket is about $20 tops and there are 3 bolts and 2 nuts holding the manifold on plus the egr bung. Then take the old gasket out and put a new one in and reinstall the manifold. I found it good to heat the engine up a little bit after the new gasket and tighten the nuts and bolts a little bit more. Hope this helps.

04-08-2009, 12:21 PM	#4 (permalink)
3dogsdad No Skills Join Date: Apr 2009 Posts: 1 Thanks: 0 Thanked 0 Times in 0 Posts iTrader Rating: (0/0% )	My 1986 had the same problem. In Texas, we need emmissions test for licensing. Mine failed with 2000ppm. Mechanic said the leak in manifold caused the 02 sensor to send too much gas, and created the ppm issue. Got an estimate from mechanic for about $400.00. I found the part on e-bay or possibly Rockauto (good source), and replaced it myself. Ii is fairly simple, once you get room under the car. Do it yourself and save. 3dogsdad