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Hydraulic Lifter Bleed Down

6K views 3 replies 3 participants last post by  302 Z28 
#1 ·
Need some input on a 96 360 Dodge pickup that is somehow getting what I believe to be air trapped in the lifters. The engine has approximately 150,000 miles on it. He has been running 0W30 lil in it since new and ive never heard the rockers clatter before. As of about a month now he tells me it will start to get air trapped in the lifters.It has plenty of oil pressure and I had him change to a 15w40 oil and a bottle of lucas oil stabilizer. No change I went with him today to about 7 miles away and as soon as the engine as started,I could hear what sounded like 5 or 6 rockers. We got about 10 blocks and they completely quit ticking until we got off the highway again. Sometimes rpms seem to fix it,but then again coming back on the highway they started up again. Then they would quit till we got into town and started up again. He always changes the oil at about 2,000 miles,so thats not it.Somehow its getting air in the oil galley and causing the lifters to bleed down.

Dont think its a worn cam as it wouldnt get better like it does or pushrods or rocker pushrod seats or mushroomed stems. Is the oil pump pickup bolted or pressed on in a small block mopar? Wonder if it could be cracked and sucking air? No leaks like a galley plug or something. Engine has never been apart. Oil pressure is steady 45 lbs. Its soo hard to analyze without it apart,but having to pull the intake isnt going to be fun.
 
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#2 ·
I was having the same problem with a 96 Dodge 1/2 ton, 360. One hunderd twenty thousand miles... Religiously changed oil. Perfect running truck.

Untill I had to use it on a two thousand mile trip!! I started out on the first leg, got just across the border into Canada. Oil pressure gauge starts to fall, lifters start to make noise. I pull off the Queens road and check the oil. Full, just like when it was changed a week earlier. Checked everytjing I could along side the road. Let it set about an hour and started out again.

To make a long story short. It would go from 60-100 miles and the oil pressure would start to descend very slowly over the next ten miles till the Idiot light would come on. Lifters start to rattle.. The big problem was when the light came on the computer would shut the guages down and ??? but the truck would still run..Lifters just hammering...

I ended up making the next 1600 miles by adding Lucas and keeping the engine below 2400 rpm. Lifters just hammering! Motorists and truckers staring!! Which got to be interesting in the mountains..with a car on the back.. I figured any engine will run on low oil pressure at that speed.. Made for a looooong trip! shades of the 55mph speed limit!!

Got it home, bought a hi-volume pump, checked the bottom end and it looked like it was just assembled, changed to synthetic oil. Seemed to cure it.

Went to NSRA Nats in Kentucky, perfect running. Then tried to haul a load of parts to K-Zoo and only made it 40 miles, lifters HAMMERING! scared me.. Let it set, then limped back home.. From that time on it ran like a new truck, till it had to pull a load.. Got disgusted with it and sold it!!
 
#3 ·
The crazy thing is,he just had mopar put in a new overdrive tranny. $2500. Now hes talking about letting em swap out the lifters. Im afraid im going to have to at least pull the valve covers and see if there are any i can feel loose. I hate new style engines.too much crap in the way.
 
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