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Installing exhaust manifolds, GM 4.3 V6 engine.

Fix A Connecting Rod Knock - GM 4.3 V6:

Engine Rebuild Part 10 -
Installing Exhaust Manifolds

May Also Apply To Chevy / GMC
350 Cubic Inch V8 Engines

In This Article: The exhaust manifold mating surfaces are cleaned up. Bolt holes are cleaned with a 3/8" coarse tap. Manifolds are installed with new gaskets, and accessory brackets are installed.	Related Articles: Index Of Engine Repair Articles Next Page: Part 11 -Oil Pump Previous: Part 9 - Cylinder Heads
Skill Level: 3 (Intermediate)	Time Taken: 1 - 2 Hours
Author: Bruce W. Maki, Editor	Project Date: August 2011

By Bruce W. Maki, Editor

By HammerZone.com Staff

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First - Installing The Oil Dipstick Tube:

Applying sealant to oil dipstick tube during engine assembly, GM 4.3 V6.

I cleaned up the dipstick tube with brake cleaner, and scraped off the old sealant.

I applied a liberal dab of thread sealant just below the ridge near the lower end of the dipstick tube.

I inserted the dipstick tube into the hole in the engine block and placed a 3/8 inch open-end wrench over the ridge. Then I hammered on the wrench with a small hammer to drive the tube into the engine. I was not able to push the tube in more than 1/4 inch... I hope the sealant blocks oil from escaping.

This will cause a problem: The dipstick will not give an accurate reading. Since the dipstick tube is too high, the oil on the dipstick will show a reading that is lower than the true level of oil.

Installing oil dipstick tube in engine, using hammer and small wrench.

Installing The Exhaust Manifolds:

Cleaning exhaust manifold mating surface on cylinder head, using Roloc Bristle Disc.

Cleaning Up The Mating Surfaces:

I used a coarse Roloc Bristle Disc to clean up the exhaust manifold mating surface on the cylinder heads. After this I used a fine regular Roloc disc to clean up the scratches left by the aggressive bristle disc.

I cleaned up the mating surfaces of the exhaust manifolds using a coarse Roloc Bristle Disc, a smooth file, and regular Roloc abrasive discs.

I also cleaned up the manifold where the exhaust pipe connects (the funnel-shaped area between the three studs).

Exhaust manifold for Chevy / GMC 4.3 liter V6 engine.

Exhaust manifold gasket or "donut" used to seal exhaust pipe to manifold.

Note the orientation of the exhaust gasket, sometimes called a "donut". The metal prongs go inside the manifold.

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Cleaning Up Bolt Threads:

On the cylinder heads, I chased the exhaust manifold bolt holes with a 3/8" - 16 tap.

To clean the bolts, I buffed them on a wire wheel and then ran them through a 3/8" - 16 die, which removed the old sealant from the threads.

Chasing exhaust manifold mounting holes in cylinder head prior to manifold installation.

Exhaust manifold with gaskets held in place by mounting bolts.

I laid the exhaust manifold on a block of 2x4 to keep the mating surface off the table, then I inserted the bolts through the holes into the gasket.

The gasket is made from multiple layers of metal and there are tabs that hold the bolts.

While doing this, I set these heat shields in place, because they are held in by the manifold bolts.

Exhaust manifold with heat shields, GM 4.3 V6 engine.

Installing exhaust manifold bolts on GM 4.3 V6 engine.

I held the exhaust manifold against the cylinder head and threaded the bolts into the engine.

Then I tightened the bolts to 11 foot-pounds, working from the middle outwards. After that, I tightened the bolts to 22 foot-pounds in the same pattern.

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The left-hand exhaust manifold after installation.

I also installed the accessory brackets on each head, just above the exhaust manifolds. These brackets hold the spark plug wires in place.

Left side of engine showing exhaust manifold, oil dipstick tube, and spark plug wire bracket, GM 4.3 liter V6 engine.

Right side of GM 4.3 V6 engine, showing metal bracket mounted to front bolt for exhaust manifold.

The right-hand exhaust manifold after installation.

Note the black-painted metal bracket (red arrow) on the left-most manifold bolt. This bolt is different from the others, it is a bolt-stud combo fastener. This fastener must go in the right place or else it could be a lot of work to move it later.

Next Page: Part 11 - Installing The Oil Pump

Previous Page: Part 9 - Cylinder Heads

More Info:

Tools Used:

Roloc Bristle Disc, 50 Grit, 80 Grit
Angle Die Grinder
Tap, 3/8" - 16
Torque Wrench
Misc. Sockets
Wrench: 3/8"
Small Hammer

Materials Used:

Exhaust Manifold Gasket Set
Copper-Based Anti-Seize
Thread Sealant

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