Our ride? The beloved '99 GC 3.3 family truckster. 132k on the clock but runs like new.....except.......

Couple weeks ago a sqweak started from the rear of the engine. Sounded a lot like an alternator bearing going out. Took it to a trusted indi shop and was told to get a new motor because the last two lifters on the rear bank were oil-starved and wearing into the shaft. The shop felt if the rockers were starved (presumably by sludge) then complete engine fail was the next problem. At my suggestion they pulled the front valve cover and found those parts to be in great shape (looked like two different motors). They replaced the bad rockers and shaft for $570 and the engine sounded smooth and quiet.

For 4 days. Then the squeek returned.

Back to the shop. They again said replace the motor (for $2500 - used) because the cam bearing was bad and it was blocking the oil passage to the lifter. I had asked them to do an oil pressure check and was told it was "OK" - but not given a number. They putit back together (with the squeak) and took another $42 from me. They wanted toput the engine on the bench to do a dignostic but I had the feeling by this time it was a precursor move to make engine replacement an only option.

My question:

Does the cam bearing story hold water? I've had many v-8s apart over the years and the that idea just doesn't sound right given there is no other issues (noise or odd vibration) that may indicate cam bearing failure. This is just a gut feeling.

My first impulse is to go after the cam for inspection - which leads me to my main question. To pull/inspect the cam is engine removal required? Can I pull the intake plenium from the top and the cam via the wheelwell?Also, is it still more likely that I'm dealing with a blockage in the passage to therocker and trycleaning that first? It's very unlikely they (the shop) removed any parts to come to the came bearing determination so my guess is they asked around and came up with a plausable explanation - and I have to admit it sounds logical. I just don't believe it.

Thanks folks. And thoughts will be apprieciated.

 

Try old faithful!! Drop a half to 3/4 of a litre of tranny fluid to see if that might unclog any oil passages that might be clogged! Change the oil in about 2 to 3 weeks after putting tranny fluid in!! Just did this in a 3.4 chevy motor(2004 impala with a noisy lifter)

 

Thanks Hessapp, but the lifters are fine. The problem is the rockers on top of the head. I did however try one of the "off the shelf" oil detergent boosters.......just in case it might have helped. It didn't.

 

I would go one step further and use diesel fuel as my cleaning agent.I wouldn't drive the van with this mixture in the engine but let it idle for about an hour while the diesel works at loosening up sludge deposits.About a quart should do the job.Use a clean drain pan and open the filter with something that won't leave metal cuttings and look for metal particles in the pleats of the filter.Let the oil sit in the drain pan while you open the filter so that the metal particles can settle to the bottom of the pan.You can use a paint filter and funnel to drain the oil into something to carry it to a recycler.Inspect the filter for more metal particles.
The particles can be aluminum,steel,babbitt,or carbon.Carbon will be in chunks that are easily smashed with your fingers and look like coffee grounds.A magnet can be used to tell the difference between steel and aluminum.The babbitt can look like flattened aluminum but will have a copper color to them as well.Large amounts of any of the metal particles will mean a rebuild or replacement of the engine.Large amounts can be anything over 1/4 teaspoon.
The squeaking sound would indicate a dry bearing and if thehydraulic lifter is running dry it should make a loud ticking sound.The rockers could have run dry but they are lubed through the pushrods and these can be cleaned out or replaced fairly easily I would think.

 

Along those same lines - does anybody know where I could find an oil circuit diagram? I'd like to find out exactly where that oil passage flows.

 

There should be a gallery drilled lengthwise (front to back) behind the lifter holes.Thispumps upthe lifters and lubes the cam lobes.The oil thenispumpedup the inside of the pushrods and runs out onto the rockers to lube the rocker and rocker shaft.It then runs by gravity back throught the head into the oil pan.

 

I have a cure for this problem,it started as a temporary repair but my neighbor has been running this fix for a year now with no problems.I am currently going to start offering to public. I'll start a post when I get them made. Thanks
Please feel free to e-mail me.

 

On the early NS 1996 thru 2000, the was rocker tower problems, the rockers on the rear head would snap off causing a misfire on number 1 or 3. The only fix was to replace the head. there was other problem with cam shaft bearings, and the cam shaft would snap in half. since the still runs I would remove the valve covers and inspect all rocker tower for cracks or being broken.

 

I just got the parts from dealer today,give me a couple of days and I will post the fix for sale. I can only sell a few until I get with my attorney.
This is a fix is for the rockers that wear through the shafts due to the oil passage being plugged by sludge or cam bearings spinning,You do not have to replace the bearing or pull motor,3.5 hr repair.Still running one from last year.

 

Okay, got 2 sets made.You can e-mail me and I'll give you more details.
I have them in the Parts sale section too.