loud noise under valve cover

[importracer300]

i have a loud noise under the valve cover i think possibly that a lifter went or some thing like that but i tryed taking the valve cover off and it wont budge from the left side of the motor where you fill the timing chain is and you fill the oil do i have to take that off allong with the motor mount to take off the valve cover or is it just being gay?

[xeroinfinity]

Welcome to AF.

Your year, make/model and engine size would be appropriate....

[importracer300]

yea sorry about that its a 1998 pontiac grand am Gt 2.4 liter!!! i wrote it really fast before work today!!!

[J-Ri]

You're in for some fun!

I just had that happen on my '98. On mine, the timing chain tensioner went out and was causing the timing to float around and making an absolutely horrible sound. http://www.automotiveforums.com/vbul...d.php?t=909803

There are no valve covers on the 2.4, just the camshaft housing. To remove them, you have to remove the front cover and loosen all the bolts holding the timing chain housing to the engine, including the ones on the water pump. While it's off, replace the water pump with a new one if it's never been replaced, they leak a lot and you have to remove the front cover and timing chain again if/when it does go bad. There are 4 bolts behind the camshaft sprockets that hold the timing chain housing to the camshaft housing. Hold the sprockets while removing the bolts, THIS IS AN INTERFERENCE ENGINE AND THE VALVES HIT THE PISTON if you rotate the engine backwards. Sorry to "yell", but it's important! Before you remove the sprockets though, check the tensioner, it's on the right side of the engine below the oil fill, so I bet that's what you're hearing. The piston should be tight against the tensioner shoe, if it's not, replace the tensioner. To reset the tensioner (it comes shipped pressed in), simply install it on the engine and torque it to the spec, I remember 89 inch pounds, but you should look it up. Overtightening the bolts will deform the housing and the tensioner won't work right. Then just insert a screwdriver between the piston and shoe, and force the piston in, it should unlock and spring out.

While you're are it, check the head gasket for leaks, as that is also common on these engines. To do the camshaft followers (they're not called lifters on OHC engines) if that is the noise you're hearing, you do most of what is needed to replace the head gasket, so if it's leaking at all, I would replace it while you've got the engine down that far.

[importracer300]

ok thanks looks like im in for a hell of a job or a hell of a payment to my mechanic!!!

[J-Ri]

It's really not all that bad, just take your time and label every single part you take off. If you have a digital camera, it may help to take a picture as you take each part off so you can look at where it should go when you re-assemble it.

I took a total of 18 hours (or would have if I had the tensioner right the first time ). That included cleaning every part to where it was spotless inside and out (except the camshaft housings because I didn't want to get solvent into something I wasn't disassembling, they are two parts, but come off as one piece). The carbon deposits on the pistons, valves, and intake added 5 hours... I'd never seen it that thick on anything before!

When you take the camshaft housings off, tilt the top away from the center of the engine before you lift it vertically because all the followers will probably fall out, they did on mine anyway. That way if they do fall out, they'll at least land on something clean. When you're ready to reinstall the housings, remove all the followers and wipe them clean, then put some assembly lube grease around them to make them stick in there a bit.

Also, put the bolts back in the housing and snug them up before you take the bolts out of the timing chain housing. The cam lobes will be holding at least two valves open, and if you don't have the bolts in the top while you remove the ones through the front housing, I'm afraid you might crack the timing chain housing because it will try to twist as the front bolts are removed. Find the tightening sequence and remove the bolts in the opposite order that you tighten them, the same goes for the head bolts if you would end up having to do the head gasket. Also, the head bolts and the camshaft housing bolts are torque-to-yield, and must be replaced once loosened.

One other thing, since the engine is interference, don't rotate the crank- or camshafts when the chain is off. If you end up rotating the crankshaft to better clean the pistons like I did, make sure the timing marks are all lined up before you put the head back on!