Hello everyone,

I have a 2001 Chevy Blazer. I have had this noise for the past 10k miles along with a suite of codes about O2 sensors and misfires and etc while there is nothing wrong with anything mentioned in the codes.

I have been told by several sources that the noise is due to worn lifters and they need to be replaced. I have a factory repair manual so getting all of that done shouldn't be a big deal but I do need some advice on potential other parts to swap out while I am in there.

I am definitely going to change all the gaskets I take out and all of the lifters. Question is, what else should I change while I have the engines top torn apart?

Thanks

 

Sounds like sticky lifters for sure, its worth taking a hollow metal tube of some sort and sticking it on the block around the lifter valley and see if you can hear the ticking noise clearer by sticking your ear near the other end, if so its definitely the case. Really the only thing worth changing otherwise is the Lower Intake gasket if its not already been done, Thermostat while the top of the motor is apart and its easy to access and check your throttle body springs.

How many miles are on the motor, and have you actually replaced the O2 Sensors?

 

I had to replace the lower intake manifold gaskets two years ago. Seems like I gotta go through it all again. I had replaced all the O2 sensors besides the one after the cat. I don't know if thosd would cause noise though. Engine reached 200k miles and it still runs fine so I think I will go ahead with the repair knowing its mostly time consuming rather than expensive parts.

 

Does it make noise all the time or only a little while after you first start it?
Are there any exhaust leaks up by either manifold?
Did you check with a stethoscope?

If it’s ticking all the time and no exhaust leak, if I were you I’d first run a can of EPR though it, then do an oil change and use a quart of MMO and the rest 5w-20 Mobil 1.
If a lifter is hanging up, doing the above might free it up and save you a little time and $

 

When I replaced my LIM gaskets, I also upgraded the fuel injectors as a preventative item.

 

Most of the noise is prominent during start up or or when idling in gear. When I rev it up it picks up in frequency but then the engine noise takes over. I don't have magic ears so I'm not sure if its ticking at 1000+ rpms, its definitely not obvious.

Only exhaust leak is before the muffler, the gasket is half chewed up. I checked the noise using a poor mans stethoscope and its definitely highest near the sides of the engine. When the noise first started I added lucas heavy duty oil stabilizer thinking it might help. I will try MMO this next oil change.

 

A quick and easy fix is to change the oil with a 5w/30 cheaper oil ( minus 1 quart) and add a quart of automatic trans fluid and run the vehicle for 1 thousand miles or so. The trans fluid will most likely clean out the sludge in the lifters. Being roller lifters they are more than likely sludged up than worn out.