2002 blazer 4.3 engine sounds like valve train noise, noisy
lifter, ticking . scan tool shows no dtc code, vacuum gage shows solid engine. steady 17 with no flucuations. any ideas.

 

Check my post of the 98 4.3 L with upper engine noise and listen to the video link I posted. I couldn't figure it out for awhile but I have after lots of research and picking and prodding etc.. If it's an upper sound, that appears to be a steady hammering sound I'd say you have a collapsed lifter that probably resulted from an engine over-rev situation that forced some sludge into one of the lifter's check *****. Whereby it got stuck, collapsed, never recovered like it's supposed to (it can't when the check ball's seat or gallery is overly contaminated) and there ya have it.

You could check all your rocker arm's mounting nuts for proper torque (like I did). Check all your push rods for straightness on a piece of glass (like I did...lol) and end up replacing all of your lifters because of contamination like I will be doing today.. .

If you're not big on oil changes like the guy I bought this vehicle from apparently didn't change his oil enough. Which, results in engine internal sludge and sediment buildup. Its a recipe for trouble.

You could pull your lifters and take a few apart, if you have a black sludgy buildup within the oil at the base of the lifter, just dump them all and buy all new lifters and install them. They're not worth cleaning.

 

check PCV valve? they are noisey and similar to tick but go away with giving it throttle.

 

how hard is it to pull a lifter? im helping my neighbor pull the engine out of his 98 jimmy (think it spun a bearing) and its not exactly easy. but jw about how many hours/days that would take for lifters.

 

You have to pull the valve covers and the lower intake manifold off. It isn't anywhere near as difficult as pulling the motor.

 

It really depends on you and the amount of experience-skill you have. If you desire to clean up the intake and plenum like I did it could take up to 10-12 hours. But I prefer to take my time so as to not miss anything. The former owner of my vehicle didn't change his oil much and there was a whole lot of grime in the engine where it shouldn't have been at all. Here's a few photos with the new GM style (4th generation) heavy aluminum intake manifold gaskets installed (GM part Number # 89017866-ACD -$50.-54.00 dealer?found them online for $30.00), valve covers back on, new lifters in place, dog bone (lifter retention bracket) bolts, cleaned and thread locker applied and torqued. We're almost there on the 24 hour cure time for the RTV sealant. Addin water the first time for a flush and new coolent if all is good. So it's just cake now!

 

Here's a video of my son's 4.3L engine in question after new lifters are installed and it's been reassembled and running again. Hellva tap and coming from number 3 cylinder for sure..

YouTube - mike's tapper.3GP

 

Sure sounds like a rod knock.

 

Its interesting. Before the lifter change it didnt quite sound like one.. lol. But now it does. I've never had to repair such a beast of a problem. Does it involve new pistons and reusing the existing connecting rods but with new bearings or what?

 

The pistons are likely fine. You may be able to reuse the rod, but that depends on how bad it is. The crank may also have to be turned and an oversized rod bearing used. It all depends on how things measure out once you get it apart.