Engine knocking sound- Recording included

[laxman21]

99 blazer.

Had the Lower intake manifold replaced a week ago. Wife said it started making this noise tonight.

Click here to watch clip



What do you guys think?

[Hunter1]

From what I can tell... I had a similar noise a few months back and it ended up being a cracked distributor cap. thats what it sounds like to me anyway.

[kb3jhp]

whats it do when you rev it does the sound speed up or quit. also why did you get the gasket fixed was it getting coolant in the oil.it sounds more like the valve train taping check the oil.and get a steatho scope and put it down on the vaulve covers,dist,ideler pully and find out where it is comeing from and then repost with what you find

[laxman21]

Originally Posted by kb3jhp

whats it do when you rev it does the sound speed up or quit. also why did you get the gasket fixed was it getting coolant in the oil.it sounds more like the valve train taping check the oil.and get a steatho scope and put it down on the vaulve covers,dist,ideler pully and find out where it is comeing from and then repost with what you find

Cause it was leaking.

[534BC]

sounds like valve, pushrod,lifter,rocker noise. Pulling a valve cover may reveal it.

[muddog321]

Agree on the valve train noise. Often the lifers got Dex Cool on/in them when the intake leaked so change the oil/filter and use the high mileage type and that should quiet it down. It should be louder at startup and quiet some as you rev up and the lifer (s) pump up. Also check the air injection check valves and rubber hoses on the front of the exhaust manifolds cause they sound similar with an open (burned thru) hose.

[kb3jhp]

Originally Posted by laxman21

Cause it was leaking.

but was ther coolant in you oil

[dmbrisket 51]

coolent in the oil DESTROYS the moter, perioud, there is no 'fixing' without a rebuild of the bottum end... you can re seal the gasket but the bearings are already whyped... it does sound like a valve train noise, as kb3 said get the stetho out and listen... a long screw driver, metal to the moter, handle to your ear is fine as a stetho

[laxman21]

Originally Posted by kb3jhp

but was ther coolant in you oil

Nope.




The sound goes away if you rev the engine fast. It gets faster if you do it slowly until 2000 rpms or so.

[kb3jhp]

thats good there was no coolant in your oil did you find out where you sound in coming from also how many miles do you have

[laxman21]

Originally Posted by kb3jhp

thats good there was no coolant in your oil did you find out where you sound in coming from also how many miles do you have

Must have been the oil pump, since I lost pressure tonight while driving.

[BlazerLT]

Sounds like something in the front belt assembly. A puller or something.

Check your distributor cap to see if it is on right and check your plug connections.

[534BC]

How about the oil pump suction? That would make a knocking and a loss of pressure.

[laxman21]

Originally Posted by 534BC

How about the oil pump suction? That would make a knocking and a loss of pressure.

It had pressure when moving and lost it at idle. The engine lost power and overheated, too. HAd it towed to my mechanic.


I hope I didn't ruin the motor, but with my luck lately.....

[laxman21]

Engine is toasted, needs to be replaced.


IS it worth it on a 99 blazer with 110k miles?