Hi. I'm brand new to this forum. I signed up to see if I can get help with a problem I have.

I have a 2000 bonneville without a supercharger. The problem I'm having I think was caused by a leaking head gasket or a leaking intake manifold which allowed coolant to enter the cylinders and get compressed which bent the valve train somehow. It started making a horrible ticking sound and didn't seem to hold any coolant. I took off the valve cover and discovered a push rod totally loose against the rocker arm. It seemed to me it had fallen through the valve lifters below and was totally loose. Has anyone had experience with this problem? Sounds like I may need to replace the hydrolic valve lifters and maybe the intake manifold. Thanks for your comments and help!

Sounds like upper intake manifold failure.
Dont drive the car untill you have it repaired. you may have bent a push rod.
Are you going to do the repair yourself?

Thanks for the response!
Yes I'm not driving it, and yes I'm doing the repair myself. I removed the push rod, and its not bent (as far as my "roll on the table" test can tell). The push rod is just making contact with the rocker.

Drain your oil right away. You have coolant in your oil. You may have collapsed a lifter in the process. Your UIM should be replaced with an APN kit or a Bob Dillon reworked intake manifold, and your lower intake gaskets should be replaced with the new GM aluminum framed design. In addition, you need to get RID of the DEXCool and go with Prestone long-life Dex-compatible coolant ASAP.

http://www.bonnevilleclub.com/forum/...e=article&k=38

In addition, there'* a sticky topic in General Chat regarding DexCool.

Ok! Great. I'll drain the oil ASAP. Is there a way to tell if the intake manifold is cracked? Or is it always guaranteed that the problem is the intake manifold?

Also, is the valve lifters visible from the top part of the engine? Thanks again!

The lifters are buried in the valley under the LIM.

It was either an UIM rupture or LIM gaskets. You need to do both, or the other will bite you soon enough.

It'* a 3-part fix:

1. Improved UIM (APN or Dillon)
2. Aluminum framed LIM gaskets
3. Lose the DEX.

You can inspect the manifold for cracks once you remove it.
The lifters can pulled with a slender magnet once the rods are removed.

In the UIM & LIM discussions, I hadn't previously read about valvetrain damage... can anyone explain how it can cause valvetrain damage? I am not real familiar with the lube "circuit". A mechanic told me hydrolock can bust the starter nose housing (torque with nowhere to go). I love driving this car but geez, if it wasn't for this site it would be a ticking time bomb for Joe Driver!

I had some similar lifter noise recently. Was it ticking all the time or just at startup? When the hydraulic lifters bleed down after sitting it seems the pushrods would have SOME slack in them.

It would get worse the hotter the engine got. There was one rocker and push rod with a lot of slack. The rest of the rockers had no slack. There was probably 1/4" - 1/2" play in the rockers and the push rods.

I'm assuming if one cylinder compressed too much liquid, a valve would get bent or something like that. I guess there was too much pressure an a lifter got broken.

You really do blow stuff up.