Pushrods On G.M. 3.1-3.4 Engines – This Is Still Going On !!!

Exhaust and Intake Pushrods on G.M. 3.1 and 3.4 engines are different lengths.  

Quite often I am seeing bent pushrods and valves when they are mixed up.

Consequently, Exhaust pushrods on G.M. 3.1 and 3.4 engines are longer than their intake counterparts.

As a result, It’s critical to reinstall the correct length pushrods in the correct place.

Pushrods
Pushrods

The most common reason to remove the pushrods is to repair leaky intake manifold gaskets.

This is the most common problem on these engines. Some have blamed the problem on GM’s Dex-Cool antifreeze, but the real problem has been the intake manifold gaskets. The original equipment gaskets have a plastic carrier and soft sealing beads around the coolant and intake ports. Over time, the plastic carrier and seals soften and deform, causing the gasket to lose its seal.

Coolant then starts to leak down into the lifter valley and crankcase. Eventually, the loss of coolant causes the engine to overheat, which may cause additional damage. Eventually leading to a cracked cylinder head or crushed head gasket. The leakage problem can occur in as little as 60,000 miles on some engines. The higher the mileage, the more likely the intake manifold gaskets are leaking coolant.

Coolant leakage can be diagnosed by checking the oil dipstick or by pressure-testing the cooling system. 

ALSO, IF THE OIL LOOKS MILKY OR FOAMY IT PROBABLY HAS COOLANT IN IT !!

If an internal coolant leak is indicated, the fix is to pull the intake manifold and replace both intake manifold gaskets. Several aftermarket gaskets offer design and material improvements over the OEM gasket to provide a longer lasting trouble-free seal.

I also recommend using a pushrod removal tool, that could also save stripping a rocker bolt.

Pushrod Remover
Pushrod Remover

Redesigned for Newer 3.5L and 3.6L GM Engines. Also Works on GM V6 2.8L, 3.1L and 3.4L.

Quickly removes pushrod so you can replace the intake gasket.  No need to loosen and retighten the rocker arm.   The tool pivots the rocker arm to compress the valve spring and free the pushrod for removal.

Pushrods
Pushrods

Exhaust and Intake Pushrods on G.M. 3.1 and 3.4 engines are different lengths.

  • The intake valve pushrod measure 144 mm (5.75 in) long.
  • Exhaust valve pushrod measure 152.5 mm (6.0 in) long.

So, how do you commit to memory which pushrod goes where?

It’s easy if you remember this short phrase…  “It’s been a long, exhausting day.”

This should help you remember that the long pushrods belong to the exhaust valves.
PLEASE SHARE ENGINE PORTAL NEWS
About Danny Bender 147 Articles
DannysEnginePortal.com Is The Premier Automotive Engine Troubleshooting Resource Site. DannysEnginePortal.com Shares Information On Engine Troubleshooting, Engine Rebuilding, Engine Repair Tips, Tech Info, Basic Machining, Automotive Testing, In Addition To Possible Solutions.

Be the first to comment

Leave a Reply