You take your Wrangler a lot of places. If you go off-road, water can splash on hot exhaust manifolds and crack them. If they crack, the exhaust leak will sound horrible—like an old tractor. Sometimes the manifold just cracks after getting some age on it. Fortunately, you have a multitude of choices when it comes to replacement manifolds. Stock cast iron manifolds can be purchased from many companies and if you want to upgrade, you can choose fabricated stainless steel manifolds. Changing exhaust manifolds is not really any fun, but as long as you have patience, you can do it.
How to Replace Exhaust Manifold
Materials Needed
Step 1 – Locate the exhaust manifolds
Lift the hood and locate the exhaust manifolds down to the sides of the engine below the valve covers. A heat shield covers them and the spark plugs are cradled by them.
Figure 1. The manifolds are deep down in an unfriendly place.
Step 2 – Remove exhaust pipe
Your Wrangler sets pretty high, but you may still need to jack it up to get the access you need to the exhaust bolts. Use standard precautions when jacking it up.
Figure 2. Exhaust bolt.
The exhaust pipes are held on by two bolts that screw into nuts with keepers to make removing them a little easier.
Figure 3. Exhaust pipe nuts and keepers.
Soak the nut keepers in penetrating fluid and allow to set; the longer, the better. Using a long extension, U-joint and 15mm socket, remove the bolts from way up in there. If the nuts twist, you will have to use locking pliers to hold them. If yours look like the ones in Figure 3, you will be happy, but If it looks like Figure 4, not so much (plus the manifold is cracked).
Figure 4. Rusty exhaust nuts and keepers.
Step 3 – Remove heat shields and manifold
The heat shields are made of thin sheet metal. The top is held on by two of the manifold bolts. Remove them with a 10mm socket and extension. The lower one is held on with a single nuts that is also 10mm.
Figure 5. Heat shield and manifold bolts visible.
Figure 6. Exhaust manifold heat shields.
Figure 7. Exhaust manifold showing lower heat shield stud (arrow).
Remove the remaining four bolts and lift the manifold and gasket off. Clean the head where the manifold bolts on. Also, be sure the exhaust pipe flange is smooth for a good seal.
Figure 8. Engine without manifold.
Step 4 – Replace the manifold
Install the nut clips on the manifold with anti-seize on the nut threads. Put the new manifold and gasket in place on the head. Put anti-seize compound on all of the bolt threads. Start the four bolts that do not hold on the heat shield and tighten finger-tight. Starting from the middle and going out, torque the four bolts to 22 ft/lbs. Start the exhaust bolts in the nut keepers and snug up the two evenly. Torque the bolts to 30 ft/lbs. Install the upper heat shield and torque the bolts to 22 ft/lbs, then the lower one and tighten the nut snugly. That does it for replacing a stock manifold.
Figure 9. New exhaust manifold.
How to Replace Exhaust Manifold
Materials Needed
- Light
- 3/8" drive ratchet set
- long extensions and U-joint
- 10mm and 15mm sockets
- Penetrating fluid
- Anti-seize compound
- Manifold
- Torque wrench
- Jack and stands (optional)
Step 1 – Locate the exhaust manifolds
Lift the hood and locate the exhaust manifolds down to the sides of the engine below the valve covers. A heat shield covers them and the spark plugs are cradled by them.
Figure 1. The manifolds are deep down in an unfriendly place.
Step 2 – Remove exhaust pipe
Your Wrangler sets pretty high, but you may still need to jack it up to get the access you need to the exhaust bolts. Use standard precautions when jacking it up.
Figure 2. Exhaust bolt.
The exhaust pipes are held on by two bolts that screw into nuts with keepers to make removing them a little easier.
Figure 3. Exhaust pipe nuts and keepers.
Soak the nut keepers in penetrating fluid and allow to set; the longer, the better. Using a long extension, U-joint and 15mm socket, remove the bolts from way up in there. If the nuts twist, you will have to use locking pliers to hold them. If yours look like the ones in Figure 3, you will be happy, but If it looks like Figure 4, not so much (plus the manifold is cracked).
Figure 4. Rusty exhaust nuts and keepers.
Step 3 – Remove heat shields and manifold
The heat shields are made of thin sheet metal. The top is held on by two of the manifold bolts. Remove them with a 10mm socket and extension. The lower one is held on with a single nuts that is also 10mm.
Figure 5. Heat shield and manifold bolts visible.
Figure 6. Exhaust manifold heat shields.
Figure 7. Exhaust manifold showing lower heat shield stud (arrow).
Remove the remaining four bolts and lift the manifold and gasket off. Clean the head where the manifold bolts on. Also, be sure the exhaust pipe flange is smooth for a good seal.
Figure 8. Engine without manifold.
Step 4 – Replace the manifold
Install the nut clips on the manifold with anti-seize on the nut threads. Put the new manifold and gasket in place on the head. Put anti-seize compound on all of the bolt threads. Start the four bolts that do not hold on the heat shield and tighten finger-tight. Starting from the middle and going out, torque the four bolts to 22 ft/lbs. Start the exhaust bolts in the nut keepers and snug up the two evenly. Torque the bolts to 30 ft/lbs. Install the upper heat shield and torque the bolts to 22 ft/lbs, then the lower one and tighten the nut snugly. That does it for replacing a stock manifold.
Figure 9. New exhaust manifold.