Lifters Tapping?

[99blazer]

I just purchased a 99 2dr Blazer 4x4. Love the truck but I had some concerns with a tapping noise I heard under the hood. It is not very noticible when at an idle but under acceleration you can definitely hear it. I asked a mechanic about it and he told me it was the Lifters tapping and it is common on chevys. He said that it was not hurting to drive the vehicle like this? Is that true?

I read here that if you use synthetic or a friction reducing oil that it might stop it. Any truth in that?

Thanks for your help.

[99blazer]

Doing some further research here, and found that it could also be the belt tesioner. What is an easy way to find out which one is the culprit.

[quaddriver]

I hope it aint the lifters....they have been rollers since 89/90

[99blazer]

Huh? Sorry I dont know much about engines. So in other words the only thing it could really be is the tensioner?

If this guy was a mechanic shouldnt he know that?

[nmoran429]

Could you possibly need to replace the exhaust manifolds?? Any leaks or holes in them?? I changed the ones on mine, much quieter ride.

[tomminajar]

Is the tensioner bouncing around at idle or if you rev it up ?

The lifter tick may be noisy Fuel Injectors- Put a long screw driver on one (if you can see one) touch it and listen to it ...

[rlith]

Originally Posted by tomminajar

Is the tensioner bouncing around at idle or if you rev it up ?

The lifter tick may be noisy Fuel Injectors- Put a long screw driver on one (if you can see one) touch it and listen to it ...

Considering our injectors are inside the intake itself, how is he supposed to do that? The 99 uses an injector pod similar to the 92-95 CPI unit... Essentially same principal (spider, with central pod) Main diff is that CPI in batch fired, CSFI is sequentially fired... Cant run without the plenum on.. Our injector pods really don't tick, they use poppets..

[tomminajar]

Drill six small holes ?!?
My bad - I just kind of assumed they dumped the cpi after those three wonderful years - I haven't been looking at many newish blazers

[crank182]

Yeah you don't want to drill any holes into your intake if thats what you're reffering to, anyway i had a similar problem to my blazer, when it's under load, giving it a lot of gas going up a hill, it'll get louder, it ended up being a small exhaust leak at the manifold, might want to check that out before you go tearing appart your engine, if you replace the manifold gaskets it should fix the problem unless the manifold itself is cracked, if you change the gasket make sure you change the bolts as well, exhaust bolts tend to get pretty ugly over time. As for the tensioner it shouldn't really make a tapping noise it'd be more of a vibration or even a squeak like noise, i never heard of fuel injectors making that loud of a tapping noise, they do tap when they pulsate but it shouldn't be that loud or even noticable because think of where the injectors are located, as for the lifters it could be making the noise, after time they do tend to make a dieseling noise when they are out of adjustment, hope this helps.

[99blazer]

Ok, today I heard the rattling, chain type noise as described with the belt tensioner problem. I plan on taking it to my mechanic here in the next few weeks. If the tensioner breaks while im driving what type of damage am i looking at?

[MeCNE]

Originally Posted by tomminajar

Is the tensioner bouncing around at idle or if you rev it up ?

The lifter tick may be noisy Fuel Injectors- Put a long screw driver on one (if you can see one) touch it and listen to it ...

What does it mean if the tensioner bouces at idle or Reved up?

Mine does..
And I have loud clunk and rattling noise when the AC pump kicks in and runs...
And sounds like a wosh wosh wosh .. when it idles. kind of anoying,.

THanks

[tomminajar]

Originally Posted by MeCNE

What does it mean if the tensioner bouces at idle or Reved up?

Mine does..
And I have loud clunk and rattling noise when the AC pump kicks in and runs...
And sounds like a wosh wosh wosh .. when it idles. kind of anoying,.

THanks

"loud clunk" is the ac compressor clutch engageing.
The tensoner should'nt be boucing wildly if it does it is worn out and could cause your accessories to slip on the belt - or the belt 'could' come off..