Got a rather large exhaust leak...

[jayinatlanta]

As soon as I start my engine, I start seeing exhaust coming up through the vents. Tonight I opened the cover and looked to see a steady stream of exhaust coming from below the spark plugs, a bit more to the rear than the front of the engine.

So, I'm suspecting a cracked manifold. I can't see the crack from underneath or overhead. I'm going to bring this thing to the Lotus dealer tomorrow.

1. How big a deal is this to fix immediately? NOTE: I stop seeing the exhaust after a few minutes of the engine running, which suggests to me that heat expansion is correcting most of the problem. But the engine management is affected--the idle fluctuates about 100 RPM.

2. How much would you think the manifold replacement would cost? I'm guessing this is the worst case scenario...any guestimates?

Thanks for any help,

Jay in Atlanta
1993.5 Silver Frost Esprit SE

>>> Edited by jayinatlanta on Wednesday 28th April 11:46

[danny tattersall]

I have just replaced my exhaust manifold and it cost me about £850 in parts. That would equate to somewhere in the region of $1500. Pretty expensive even though I did all the labour myself. Judging by your description though you may just have a couple of nuts that need tightening a little. The slight expansion when hot is sealing the manifold so I would not suspect that the manifold is cracked.

Good luck.

Danny '93 SE Highwing.

[johnwatkins]

Hi Jay,

If you're seeing oil smoke rising off the engine when you first start it up then the problem sounds more like oil running onto the manifold from leaking cam cover gaskets.

A very simple task to fix

Does it sound like the exhaust manifold is cracked, are you seeing a redction is turbo boost?

Cheers,

John W
'95 S4s

[MikeyRide]

Dumb question: are you sure it's not burning oil off the manifold? An exhaust leak there makes a pretty distinct noise (tic, tic, tic) which you didn't mention, and there shouldn't be much smoke. The "smoke" you normally see from the pipe on cold start is just accumulated moisture evaporating off from the muffler.

[jayinatlanta]

Thanks for the responses.

Yup, I'm sure it is exhaust rather than oil. And I just got the news from the dealer:

Catalytic Converter is split wide open. Also a hole in the exhaust pipe itself. Manifold is fine.

So now what I am looking at for cost? Anyone know? Can a typical exhaust shop do this?

[Dr.Hess]

Sounds like a backfire. From what I hear, OEM cats are a bit pricey. I don't see why a decent muffler shop couldn't cut out the old one and weld in a new high-flow.

On Toyota motors, people have found on a dyno that the Toyota OEM cat (in good condition, of course) does not rob horsepower.

Dr.Hess

[jayinatlanta]

Since I have a hole in my pipe, I think it might be a good idea to have a performance exhaust shop craft a custom exhaust + high-flow cat. I know a good shop so if the dealer price is too high, I'll try that.

Thanks again.

[rlearp]

You can get brand name high flow cats for about $200 off of Ebay. Same thing Jegs sells for $450. I bought one for $165 and it is 3" in and out. Couple that with some good 3" mandrel bent pipes and you'll be in good shape. You might want to buy the parts yourself to avoid the upcharge the shops will put on the items, catalytic converters are notriously high at shops.

Ron