: Exhaust manifold ?



PerryT
12-09-03, 10:53 AM
The engine in my '94 STS makes a ticking sound during medium to hard acceleration. I suspect it is an exhaust leak. How hard is it to get to the exaust manifolds on the N*? I can't even see them from above the engine and I haven't tried looking from under the car. Is it a major operation to replace the gaskets? I have a feeling it won't be as easy as working on my '70 Mustang. I appreciate any help or advise.

Perry

eehoepp
12-09-03, 10:26 PM
The front exhaust manifold gasket should be relatively easy to do. Relative to everything on this engine to be limited access, that is. You will probably have to support the engine and remove the front engine mount bracket (or at least unbolt & position out of the way) to get at the front manifold.

I had the rear manifold off when I had the powetrain out of my car. I don't think it can be done with the engine in the car.

There have been other threads about ticking under acceleration. I THINK it had to do with starter/flywheel clearances. Search the forums and see what you can find.

Good luck.

growe3
12-09-03, 10:30 PM
These engines rarely have an exhaust leak, but on the off chance you do....

I would first check the connection where the exhaust pipe connects to the catalytic converter for signs of leakage. If it looks like it has been leaking, and the bolts are tight, unbolt the connection, look in see if the catalytic converter is showing signs of blockage.


Sudden or prolonged acceleration and a partially blocked converter will build up backpressure and push off the exhaust pipe. The exhaust pipe is held in place by two bolts with springs. The springs act as a pressure relief to avoid dangerous/harmful pressure buildup.

Looking into the converter, the "honey comb" should look light tan to white in color and not exhibit any sign of blockage. If all is OK bolt it back together (there is no gasket at this connection).

The exhaust flange bolts to header bolts are a little harder to get at. You must get at them from the bottom of the car. You will need enough 3/8" drive extensions to reach about 2 1/2 feet and a couple of metric sockets.

The two nearest the center of the car take a 15 mm socket. The two nearest the driverís side take a 10 mm socket. The bolts are the same diameter but use different size heads to try and make it easier to tighten.

Tighten to approximately 35 lbs each.

If you have to replace the flange to header gaskets, that is another story. The gaskets should be good, they are made of a very high temperature material and soft; hopefully tightening them will do the trick

Good luck, George