pushrod problems
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New User
Joined: Jul 2010
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pushrod problems
Hey there guys I just got an 89 F-150 with the 5.0L, and came on here for a little bit of help. the truck sat for about two yearsand fired right up but keeps bending pushrods on the intake valves, I'm not too sure wat it could if anyone has any info it would greatly be appreciated.
Fleet Mechanic
Joined: Sep 2003
Posts: 1,716
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My guess would be crap built up on the shafts of the intake valves causes them to seize intermittently in their guides. A long-sitting engine seems to increase the chances of sticking.
I had a '83 302 with 130k+ miles that sat for a while before I bought it cheap. I found a bunch of bent intake pushrods when I had the intake manifold off to fix a gasket leak. Though bent, they would still open the valves. With the intake manifold off, I rotated the crank with a breaker bar, and could look at the valve stems through the intake ports in the heads. The intake stems looked awful. Crystallized carbon all over them.
I then removed and rolled on a flat surface each pushrod. Replaced any bent rods. Then turned the crank to put each cylinder one by one on their intake lobes, so intake valve opened to the max. Then hit each opened valve's stem smartly on top with a plastic hammer. I wanted to really open the valve, to be sure that the pushrod wasn't pressing against a tight valve that wasn't quite open all the way due to crud. Seemed to work, though I never took it apart again to check. But it kept running well, so I figured they were still OK.
I had a '83 302 with 130k+ miles that sat for a while before I bought it cheap. I found a bunch of bent intake pushrods when I had the intake manifold off to fix a gasket leak. Though bent, they would still open the valves. With the intake manifold off, I rotated the crank with a breaker bar, and could look at the valve stems through the intake ports in the heads. The intake stems looked awful. Crystallized carbon all over them.
I then removed and rolled on a flat surface each pushrod. Replaced any bent rods. Then turned the crank to put each cylinder one by one on their intake lobes, so intake valve opened to the max. Then hit each opened valve's stem smartly on top with a plastic hammer. I wanted to really open the valve, to be sure that the pushrod wasn't pressing against a tight valve that wasn't quite open all the way due to crud. Seemed to work, though I never took it apart again to check. But it kept running well, so I figured they were still OK.
Elder User
Joined: May 2010
Posts: 586
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From: Salisbury, MD
I just purchased an 89 F-250 with a 5.8L. I got it cheap because the guy selling it thought it had a rod bearing going up. Turned out to be a push rod. I will be puttin in all new rods and rockers sat. When we pulled the valve covers off you could see how it was abused by the deposits. and you could see on the rods where the were rubbing. As far as a cleaner you could try the Seafoam and also just changing your oil and switching to a heavier weight oil will help clear out the deposits. I will post how it goes.
