My 99 Blazer has 132k on it and runs fairly decent.

I'm having issues getting the engine to put out heat to the heater core (see my other thread in this forum).

I decided to run the engine up a bit (80MPH 3k RPMs or so) to get the engine warmer. I did NOT work. I had done this the other week and the heater started blowing hotter.

Anyways, when I got off the highway I noticed the engine developed a loud ticking noises. It's the same speed as the valvetrain so I'm guessing a lifter crapped out when I ran up the engine.

Is it still safe to drive my truck or will a collapsed lifter blow up my engine ?

Short of ripping the engine apart, what's the best way to free up a collapsed lifter ?

 

It's a loud ticking noise?