I have a 1996 Blazer 4.3 liter 4X4 and a week ago it started making a noise like a rod knocking. It has been getting worse and worse, noise wise, and today and my oil pressure dropped to 0 while idle at a stop light. When giving it gas I have plenty of oil pressure so I drove it to work and parked it. I started it again 2 hours later to have a friend listen to it and I do not have any oil pressure problems. Any ideas?

 

I am having the same problem on my 94 blazer. its a vortec 4.3, i have had it looked at and someone said it is a lifter going bad, but im not exactly sure.

 

most commom cause for a tick or knock noise is a bad lower intake gasket. check to see if you are loosing coolant, if you are thats the problem. antifreeze leaks into the lifter valley and mixes with the oil and makes it thiner, the oil/antifreeze mix cant pump up the lifters and causes excesive lash. when you replace the lower intake gasket, but the metal felpro one, not the plastic one. and then flush your antifreeze out of the block, heater core and radiator, then refill with the green stuff. the orange dex-cool corrodes alluminium parts and plastic intake gaskets, the green stuff doesnt.

 

As far as the intake gasket goes... will it cause a loss of power and a really cruddy running engine too?

 

The 4.3 Vortec seems to made noises. The drop in oil pressure would concern me. You could have a spun cam bearing you could have a main bearing issue. I have seen rod bearings spin & not blow out for a short while. If it was just noise & not getting worse & not dropping oil pressure I would say it sounds like our 97 Blazer 4x4. The engine has rattled & knocked for almost 60,000 miles now. It doesn't get worse & runs 20PSI @ idle hot & 40 PSI hot above idle. 60PSI COLD. That is what it has run for the two years & 60,000 miles we have driven it.

 

it will run like crap but i never head of it causing a loss of power, that seems like a fuel issue to me.

 

I got a 1996 chevy blazer with the same problem we had a bad snow here a few months ago i lost oil pressure but kept coolant pressure. i have been told so many things. I just want to know what the problem is and how to fix it if it can be fixed