Mechanics

CHEVY INTERMITTENT VALVE RATTLING

1999 Chevrolet Suburban

Engine Mechanical problem
1999 Chevy Suburban V8 Four Wheel Drive Automatic 90600 miles

I have an intermittent valve rattle in my Suburban. It usually will only present it's self when the motor started and has been cold for several hours. Most of the time, it rattles for up to one minute, usually less. Oil is up to spec, changes every 3k with new filter. It may go weeks with no trouble, then will rattle every day for a week then quit. Gas milage has not changed, spark plugs show clean burn, good plug wires, distibutor cap and rotor in good condition. This has been intermittent over the last two years.
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Netstarrider
October 14, 2010.



Start by measuring oil pressure with mechanical gauge.

What weight oil do you use?

It is especially important to see what OP is at startup.

Make sure oil filter has anti-drainback valve.
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Mmprince4000
Oct 15, 2010.
OIl weight is 10W-30. Electronic gauge reads 50 lbs at startup. Is the only place to attach a mechanical gauge at the same place as the sensor for the electronic? Have been using the same service place for 16 years and have faith that they are using the right filter.

Tiny
Netstarrider
Oct 15, 2010.
Yes just remove oil sender and screw in mechanical sender.

If mechanical pressure is good, then possible adjustment issue with lifter or bad lifter.

Mmprince4000
Oct 16, 2010.
I installed a mechanical oil pressure gage. Oil presssure on startup is 45 lbs cold. With the engine properly warmed up and driven 15 miles, oil pressure is at 14 at idle.

Tiny
Netstarrider
Oct 22, 2010.
It is possible you have a loose oil pump pickup or bad pump.

Change oil and look for metal particles in oil, using a magnet.

If present, then main, cam bearings, clogged oil galley.

If no metal is present, I would remove oil pan and inspect pump and pickup.

http://www.2carpros.com/forum/1999-chevy-suburban-intermittent-valve-rattling-vt515693.html

Mmprince4000
Oct 23, 2010.
Changed oil pump, added new oil (back to 5w-30), and new oil filter with anti-drain back valve. Oil pressure has increased across the range 15 psi and rattling has gone away. Thanks

Tiny
Netstarrider
Nov 14, 2010.

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