I have a 2000 ZR2 with 220k miles. A couple of months ago my lifters (maybe 3) started taping, I thought, well its time to buy new lifters, But first, I got on the forum to see what i could find. One person said it could be the lower intake blown and getting liquid on the lifters and washing the oil off. That did not sound right to me, i was thinking the lifters was losing their prime as it only did it when it was cold and would stop taping after two or three minutes, it would also skip until the lifter pumped up. I checked the oil level and it was about three qts over full. I am going to pull the drain plug off the oil pan and see if any antifreeze come out, If so i guess my lower intake gasket is bad. Question is, should i go ahead and get new lifter or is the liquid actually washing oil off the lifters. Thanks for helping

 

I have not had the LIM gaskets fail but I learned as much as I could about this as soon as I learned this failure could ruin an engine. I then replaced them.

With that in mind, take my thoughts as a starting point for what to consider:

• If the LIM gaskets have failed, there could be quite a bit of damage to the crank and connecting rod bearings. However, if all you are hearing is the lifters making noise, perhaps that is your only problem.
• Along with the oil being overfull, did you notice a corresponding loss in coolant?
• If the reason the lifters are making noise is only because they have been starved of oil, they might be ok once you get rid of the coolant and oil can get to them again. However, since you are in there doing the LIM gaskets anyway, it might be good to replace the lifters since to open up the top of the engine again would be a major hassle. They are roller lifters so that means the cam might not be worn down/wiped. (Perhaps someone with more knowledge of this will chime in)
• Be sure to get the upgraded Fel-Pro LIM gaskets to do the job. These have a metal carrier for the sealing surfaces. The Fel-Pro website can get you the part number
• I also replaced the fuel injection spider while I had the whole thing apart. However, if there is any question that after you replace the LIM gaskets that the cam or bearings are shot, you'd be wasting your money on a bad motor.
• Do what you can to get the issue properly diagnosed before you commit to doing all of the work necessary to replace the lifters and LIM gaskets. It is a pretty involved job.
• Here is a good link that describes the process of replacing the LIM gaskets. Pay close attention to the re-installation of the distributor.

Good luck

 

What weight of oil are you running?

It's certainly not uncommon for higher mileage engines to develop valve tap, it's more worrisome if it doesn't lighten up or go away after the engine warms up...

Many people have always chosen to run the next weight up in oil to stop the noise since the clearances on the older worn in motor have gotten larger. If you're running 5w30, try running 10w30 and see what happens. The oil will be thicker when cold and it might quiet down or possibly even eliminate the cold start valve tapping.

I would pull the valve covers and check valve lash before I jumped right to a collapsed lifter. Ideally this is done with a warm engine, but that's a little difficult to do in the 4.3 Blazer... But I think specs are out there on the interwebs about valve lash settings.

I'm by no means not saying it doesn't happen, but it's been a while since I've heard of someone's 4.3 (or 5.7 V8, since that's what the 4.3 is based off of...) having a valve collapse. It DOES happen, but usually when it does it's when someone's running a hopped up motor with a higher lift cam and some stiffer valve springs, not a bone stock motor.

 

I finally had time to pull the oil pan plug to see if any coolant came out, none did. The temp gauge has been showing it has been getting hot, not in the red but between 210 and 240, sometimes it runs on normal but it does get hot and falls back. I have recently replaced the thermostat and water pump. I think i will replace the lifters and lower intake gasket and hope that will fix it

 

I'm concerned that you said in your original post that the oil was overfilled by 3 qts. From where did the extra oil come? I've heard of the coolant mixing with synthetic oil to create an emulsion that looks a bit like chocolate milk. What did the oil you drained out look like?

 

My bad about it being 3 qts to much oil. i realized the front was on a rise and the oil went to the back of the pan. I got it on level ground and it was ok. My oil looked good but it has only 7 or 800 mi on it since the last oil change.. now i am wondering why the temp gauge is showing it going back a forth between normal temp to almost in the red. I am having to put a lil coolant in it every few days, geez, i just dont know

 

Any other symptoms?

White smoke from the tailpipe?
Rough idle?
Bad acceleration?

Do you have the ability to stop anytime and check coolant temp i.e. with an IR thermometer (thermometer gun)?

Wiring of the sensors in the engine bay?

About that lifter "tapping". Does it still have that issue?

 

The engine runs great, no white smoke from the exhaust, runs like a champ, except, when i first crank it up in the morning the lifters taps, only two or three and it misses on these cyl. until the engine warms up and the taping stops and so does the miss. It runs great the rest of the day. only does the taping after setting over nite.

 

May need some attention, maybe checking valve clearances as well, not that something has built up clearance.

Good luck with it and that it may only be the lifters bleeding a bit too much over night.