Originally Posted By: ArrestMeRedZ
Originally Posted By: 96Vortec
This is my first vortec. What commonly fails on these engines in your experience. Whats your mileage?
Intake manifold gaskets. Yours have probably already been changed out, but watch it in case they weren't, or were replaced with the gaskets that were the original bad design. 1996 was the first year for the use of Dexcool, and those gaskets combined with Dexcool were a problem. Mine went at 66k. Other than that, my engine has been bulletproof.
Cheap parts, easy to work on, and reliable to boot, other than the gasket problem. I have used synthetic oil from the start, and haven't had a leak yet. Factory recommendation is for 5W-30 anywhere, with 10W-30 acceptable for non-freezing weather conditions.
+1. Id do an oil change, with a quick 500 mile OCI on the same oil, just to get consistent oil in there, then pull a UOA after 1000-3000 miles on the second change.
Look for telltale signs of a LIM leak.
If you have a diagonal radiator neck, check the cap. Plastic caps are bad. Stant caps at least were good.
Id do a change of the coolant regardless. My truck has all original, clean and bright cooling system, having never seen anything besides dex cool. Dex isnt bad in an dof itself, with new gaskets at least. Mixing it with other stuff like green coolant is. Rebaseline it by changing out the radiator and then after 1000 miles doing the radiator again, that will get >50% out at least. Any signs of brown sludge and you may need to be a bit more aggressive and/or flush the block.
Why not get some fresh Dex VI in there too, if you trust that the AT has been serviced before?
plugs, wires, and distributor all ok?