I recently had this issue with my 99 Blazer...it sounded like a lifter on the aftmost cylinder on the left hand side of the engine was sticking until the engine got warmed up. My assessment was that there was lubrication issue, because the problem cropped up in the location that was most remote from the oil pump.
A clue bird flew past me when I saw this post on an oil filter page...the post concerned the Fram Extra Guard oil filter:

"Fram Extra Guard PH8A
This filter cartridge has a small outside diameter with a rather low filter element surface area (193 sqin), and features cardboard end caps that are glued in place. The rubber anti-drainback valve seals the rough metal backplate to the cardboard end cap and easily leaks, causing dirty oil to drain back into the pan. If you have a noisy valve train at startup, this filter is likely the cause. The bypass valves are plastic and are sometimes not molded correctly, which allows them to leak."

(His page is an interesting read...here is the link:
http://people.msoe.edu/~yoderw/oilfi...lterstudy.html)

As luck would have it, I had been using a Fram Extra Guard filter on my Blazer. I did an oil change and switched to an AC Delco PF 52 and while I was leak checking the oil change, the ticking went away. The next time I cranked the engine, there were 3 ticks of the lifter, then a smoothly running engine. Since then, there have been no more recurrences of the valve noise at startup.
The theory expressed in the page quoted above goes like this: 1) the Blazer has a horizontally mounted oil filter. 2) If your vehicle has such a filter arrangement, then the anti-drainback valve of the filter must work well, because 3) If the anti-drainback valve on the oil filter does not do its job, then the oil in the oil filter will partially drain back down into the crankcase after you shut the engine off, leaving a partially filled filter. Then 4) when you go to start the engine, the valve train will be deprived of oil for a while until the oil filter can be filled up by the oil pressure and the oil can circulate to the valve train.

If you drive a vehicle with a vertically mounted filter, especially if it is mounted with the gasket facing up, so that when you remove it, it is filled with oil, then the anti-drainback valve would not cause an issue.

If you look at the gasket end of a new filter, you will see little holes on the perimeter of the filter...those are the holes through which the dirty oil flows into the filter. As the oil flows into the filter, oil pressure forces it past a neoprene rubber seal....that is the anti-drainback valve that is referred to here. When the engine is shut down, the neoprene rubber anti-drainback valve prevents the oil in the filter from draining out the small holes and back down to the crankcase. If that seal is wimpy, it doesn't do its job, and it's not an anti-drainback valve any more, it's a pro-drainback valve.

I did cut open the suspected bad filter to examine the anti-drainback valve, and there was nothing obviously wrong with it...but the design features a pretty weak approach to holding back the oil. I also cut open an identical new Fram filter and a new AC Delco PF 52 and when I show the internals of the two new filters to folks, they all agree that the AC Delco arrangement of the anti-drainback valve is more robust. There are lots of other good oil filters out there...check the oil filter discussion on this forum for more on that topic.

So the lesson for Blazer owners is this: if you have valve noise on startup, the anti-drainback valve of your oil filter may be causing the issue, and you may be able to quiet the engine just by changing the oil filter over to a high quality filter with a known good anti-drainback valve. It's an inexpensive and quick fix to try.

Hope this helps somebody !

MrBill99

 

This just started to happen to my 99 Blazer. Shut it off last night, it was fine. Started it this morning and it was just rapping. Sounded like no oil at all. The oil pressure was good and the oil was full. After running for about 5 min. it was quiet..thanks for the heads up. That is the first thing we're gonna check. It does look like a Fram oil filter on there now.
I'll let you know what happens

 

I want to thank everybody for their input. I had the oil changed (we live in a townhouse) and gave them an AC Delco PF52 that I purchased. Oil was changed with the new filter. Guess what? The ticking has stopped!!! The AC Delco will be the only filter I will use from here on out. I love it when it is something simple; I do simple so well!! ;-)

 

Glad it was something so simple! What brand of filter were you using before?

 

I think they were using Frams.