3.4 Chevy Motor Problems

by Richard Rowe
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Image by Flickr.com, courtesy of Mike Licht

The Chevrolet 3.4L (3400) V6 is just one variant of a huge family of 60-degree V6s in production since 1980. Though this engine has seen constant improvement over the years, no amount of evolution will ever eliminate all of GM's notorious engineering flubs. One stands above all others in this engine family as both easily preventable and endemic, but is nonetheless responsible for countless engine failures and malfunctions.

Cooling Woes

The main cooling system problems with this engine are manifest in those cars with the third-generation engine, produced i the 1994 to 2003 model years. The problem begins as a minor external cooling system leak and eventually develops into a full-blown flood. Less-observant owners have often tfound themselves sitting on the side of the road with an overheated engine and a sizable repair bill.


The problem is that, for whatever reason, GM didn't realize that it's newest super-coolant DexCool was going to eat the intake manifold gasket. The intake manifold lies in between the engine's cylinder heads and carries not only air and fuel, but water. The water that flows through the manifold is extremely hot and under a great deal of pressure, meaning that it can put a lot of strain on the gasket-mounting area. Combine this with DexCool's corrosive nature, and it's small wonder that owners have had problems.

Fluid Flush

Though a complete fluid flush and replacement with standard "green" anti-freeze is possible, there is no guarantee that you will get all of the old coolant out. DexCool and green anti-freeze are like oil and water; the two will not mix in your coolant system, and their separation will ultimately cause cooling system failure.

Gasket Replacement

Some owners have replaced 3.4L intake manifold gaskets enough times to do it in their sleep. This has been the default solution for many years, but a more permanent one was offered by GM a few years ago. The General opted not to replace the corrosive DexCool that came stock and has instead offered for sale a new intake manifold gasket that should resist breakdown.


To be fair, the 60 Degree V6 has always been a fairly reliable and low maintenance engine family. The fact that they are well known to survive hundreds of thousands of miles of abuse may be of some comfort when it comes time to shell out $700 to replace your intake gasket (average, includes parts and labor).

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