Exhaust manifold removal and re-installation on the 1996 Saab 900 (4 cylinder turbo). The manifold had to come off because there were two broken studs on the driver side of the manifold. The gasket needed a replacement too.

Tools:

  • 13 mm socket: manifold, turbo and steering pump nuts;
  • two 13 mm wrenches: manifold, turbo and steering pump nuts;
  • 10 mm socket: air filter housing;
  • 7 mm socket: hose clamps;
  • Torx T27 socket: PCV line;
  • ratchet handle;
  • torque wrench;
  • long 1/2" socket extension;
  • 4 mm Allen key;
  • drill with cobalt bits and right angle attachment;
  • a piece of metal pipe or a hose coupler that fits the stud holes;
  • small mirror;
  • screw extractors;
  • tap wrench (optionally with a 8x1.25 mm tap);
  • car jacks and stands or ramps.

 

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23.04.2005: Manifold
I had a misfortune of having a couple of studs go on the exhaust manifold. One day they just disappeared, leaving two gaping holes in the manifold. The studs were broken flush with the head.

 

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23.04.2005: Broken studs
A close-up of the problem area. In my case it was not enough to just drill the studs out, because the gasket moved and was partially blocking the port (and causing a leak too). Therefore the entire manifold had to come off.

 

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23.04.2005: Intake
The first step is to remove the intake. The airbox cover comes off with the intake pipe and the return line from the bypass valve. Plug the turbo inlet pipe immediately, you don't want any dirt to get in there.

 

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23.04.2005: Belt
Loosen the belt with a long 1/2" socket extension and lock the tensioner with a thin Allen key. Remove the belt from the steering pump pulley. This picture shows the airbox still in place, but it's actually better to remove it before starting on the pump. The airbox is secured by three 10 mm nuts.

 

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23.04.2005: Steering pump
The steering pump bracket is attached to the head with two bolts on the top and one under the pulley (use a 13 mm socket or wrench here). The lower bolt is a bit of a pain to get to. Unbolting the metal PCV vent pipe from the valve cover gives you some extra room.

 

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23.04.2005: Turbo studs
The manifold to the turbo nuts are next (13 mm). You can see that all nuts have been generously sprayed with rust solvent last night. That helped!

 

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23.04.2005: Manifold studs
The nuts on the remaining manifold studs come next. The three studs in the middle are short, while the outer ones are long and have cylindrical spacers on them, designed to help with deformations occuring at high temperatures.

 

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23.04.2005: Nuts removed
The leftmost nut took the stud with it, but the rest came off without a fight. The WIS calls for complete turbo removal, otherwise there's not enough room to get the manifold off the studs on both sides. We chose to remove the manifold studs instead, since we planned to replace them anyway.

 

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23.04.2005: Turbo stay
An extra wiggle room is still required to remove the manifold. It can achieved by unbolting the downpipe from the turbo, and the turbo stay from the engine block.

 

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23.04.2005: Hose coupler
This brass hose coupler has been found at the local hardware store. It was a snug fit to the manifold and worked well as a guide for the drill bit, helping to ensure that we start drilling at the centre of the stud. A small mirror came handy to peek into the hole to observe the results.

 

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23.04.2005: Drill
The right angle drill extension is needed since there is not enough room to fit the drill in front of the head. I initially purchased a set of left handed HSS drill bits, but they didn't last long enough as the studs were too hard for them. This set of cobalt bits was much better suited for the job.

 

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23.04.2005: Stud removal
The remaining manifold studs were removed using an old trick with two nuts tightened together. The short stud closest to the two previously broken ones also broke after we attempted to remove it. Fortunately, it left a piece long enough so we could grab it with vice grips and unscrew the stud later when the manifold was off.

 

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23.04.2005: Manifold
Here's the manifold off the car. You can see than its mating surfaces and the gasket are still clean where the nuts were tight, but the fourth cylinder area is covered with soot on both sides.

 

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23.04.2005: I.N.P.
My father happened to be visiting from overseas and didn't mind getting his hands dirty. He helped a great deal and made the job much easier than it would have been if I did it alone. Thanks, dad! ;)

 

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23.04.2005: First
With the manifold off, it was easy to drill the holes deeper. Then, after some struggle with a screw extractor, the first stud came out.

 

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23.04.2005: Second
And then the other one.

 

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23.04.2005: Extractor
Here's the remaining part of the broken stud as it came out of the head.

 

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23.04.2005: Stud
You can see a close-up of the hole we drilled in one of the studs.

 

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24.04.2005: New parts
About $60 worth of parts: new gaskets, studs, nuts and washers. The big gasket goes its metal side to the manifold, soft side to the head.

 

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24.04.2005: Turbo gasket
Time to clean the metal shavings and dirt, and pull the rug out of the turbo housing. The gasket goes on.

 

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24.04.2005: New studs
The manifold slides onto the turbo side studs first, and then new studs can be screwed into the head. Some were easy to put in, some requred the two nut trick again.

 

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24.04.2005: New studs
After all the studs are in, start putting the nuts on. Do not tighten them yet, just put the nuts on both the head and the turbo side. Tighten the turbo stay on the engine block.

 

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24.04.2005: Tightening
Tighten the nuts on the manifold and the turbo to 16 ft-lbs. Connect the downpipe to the turbo.

 

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24.04.2005: Steering pump
The steering pump bolts are hard to reach, especially the bolt below. There's only enough room to turn the wrench 1/12 of a turn.

 

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24.04.2005: Belt
Put the belt on and attach the vent pipe to the valve cover.

 

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24.04.2005: Done
Install the airbox and enjoy the job well done.

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