Exhaust Manifolds

Removal and Installation

Removal - L4 models

"I tried to remove the Oxygen sensor, but instead of coming loose, the exhaust manifold broke."
I had to replace my exhaust manifold on my '84 for the same reason. It was actually very easy, just time consuming. If I remember correctly there are 9 bolts holding the exhaust manifold (em.) to the head. Those came out fairly easily, just remember to use penetrating oil before breaking off the bolts! The hardest part of the whole thing is removing the two bolts connecting the em. to exhaust pipe. These two where rusted so much I had to get a hacksaw blade in there to cut them in half. If you have to do this be extremely careful to avoid puncturing the pipe. In my '84 there was a good amount of space to swing a wrench, but to get at the em. to exh. pipe bolts use a breaker bar and an extension. If you have someone to help you they can locate the socket on the bolt while you lay under the car. That way you can swing the ratchet 360 degrees. Don't worry about breaking these, you will have to replace them anyways, and the broken piece will be in the em. which you will toss anyway. Remember to disconnect the battery or the extension bars may have a chance to hit the connectors on the starter. I hope this is detailed enough, good luck.

From: Richard Simmons

Removal and Repair - V6 models

A few recent messages from people with exhaust manifold questions and problems may find this of interest. To these guys, feel free to contact me if you need more details on this experience of mine.

The engine ticking noise that once was, is no longer. This engine sounds like it's a day old now. The removal of the obstructive metal in the manifolds seem to have added a slightly better sound, along with a small but noticeable increase in horsepower as hoped. I am thrilled with the outcome.

I would NOT recommend doing all this work for the hp increase alone, but it is certainly worth it, if the manifolds are off for other reasons.

As I wrote in August, my engine had a sewing machine sound to it when accelerating. Someone on the net thought that it could be an exhaust manifold leak. Listening closely to where the noise came from, I felt this could be my problem. After I removed both manifolds, I inspected them and their gaskets, finding numerous leaks. Four of the six ports had some sort of leak. Black soot made it easy to diagnose. One port was cracked where the stainless pipe mates to the steel foot. Three ports leaked through the gasket, the result of loose bolts. There was also a crack in one manifold near the crossover pipe fitting. All the leaks surprised me because there was no indication of leakage, other than the engine ticking noise. Engine operation seemed fine. I could not see any soot without first removing the manifolds, so inspecting them prior to removal revealed nothing.

I decided to repair the old manifolds, rather than buying new ones. After all, I planned to mill out the obstructive material, then reinforce them by welding ring beads where the stainless pipe meets with the steel feet. I had the cracks re-welded as well. A welder did all the work on both for $30.00 total, much less than $170.00 for one new manifold. I gave him the manifolds bolted to hardwood to minimize foot planarity problems. Also, I soaked the feet in muratic acid to strip off the rust, insuring a good weld. When I got them back from the welder, I touched them up with a belt sander to perfect their flatness.

Another comment... I was the guy asking the V6 owners if their manifolds glow red in the dark, upon a cold startup, like mine did. Well now after all this work, my manifolds still glow, but somewhat less. If this is so, it may be due to the reduced restriction, resulting in lower underhood temperatures.


...assuming you have manifold cracks and/or leaks, and have had all the recalls done already.