I have a 95 Intrepid with the 3.3 liter engine. We have had lifter noise that started last winter. Typical, noisy at start and would leave after warmup. A couple of weeks ago the noise return with avengence and the engine ran rough. I have started to tear down the top end and I ran into a broken rocker tube boss. The lifter that was noisy was also next to the broken boss. The boss that was broken was at the end of the train, in the back on the #6 cylinder. What I am wondering is what would cause the rocker boss to break off like that. The car was driven by my daughter about two miles with the loud lifter. If the lifter collapsed, could the pushrod fall out of position and jam up under the rocker hard enough to break the head?
Usually the pushrod will bend and cause no damage to the head. The bosses or any guide can break because of poor manufacturing (they’re just cheap). You wouldn’t spend a lot on that part when it will work for ten years anyway and maybe forever. Pontiac used to have steel guides made of stamped sheet metal and, impossible as it may seem, the end would break off. That’s why it is a good idea to fix it without too much delay. I’ve delayed too long about a dozen times myself and still haven’t learned.