4.3 Engine Tap

[Sierra89]

Hi all, my 95 blazer with the 4.3 vortec has started to knock. Its louder when its cold then gets more quiet as she warms up. Still runs and drives great. Does this engine suffer from the same valve tapping that the 5.3 V-8 is known for?

Thanks,

[unit731]

My 1990 Chevrolet 1500 with 4.3.

 

I got used but with all documentation and copy of all service work.

 

The original owner complained from day one about same noise. Original owner had truck for first 8 years then I had truck for another 10 years. Still same noise. Always ran great and I never had to do any engine work.

[Draenor]

There is a big difference between a knock and valve tap. Are you sure its a knock? Can you tell if it is comming from the bottom end?

[Sierra89]

After a quick inspection I am wondering if its not a leaky exhaust manifold. The exhaust system is starting to go and the tap seems to be coming from the bottom end. It sounds like a constant ticking. Its also not going away as much when the engine is warm now.

[Draenor]

After a quick inspection I am wondering if its not a leaky exhaust manifold.

Thats was gonna be my second guess, if it wasnt the "knock".

[Sholman5401]

Hi all, my 95 blazer with the 4.3 vortec has started to knock. Its louder when its cold then gets more quiet as she warms up. Still runs and drives great. Does this engine suffer from the same valve tapping that the 5.3 V-8 is known for?

Thanks,

 

 

More than likely, your probably right. I Drive a 91 s-10 Blazer and I had a ticking. Found out it was do to loose exhaust Manifold. and it caused most things to heat up alot quicker and being in the north currently it cools down alot quicker cause my Cad Coverter Cover to become loose. Which made a ticking sound that when a way when things warmed up and expanded. Its either that or a lifter. If I'm not mistaken I think you have a roller lifter not a flat head. But you said the noise was coming from the bottom so never mind. Good Luck