Just under 2 months ago upon starting our XJ we heard a problem. Ended up getting it towed and diagnosis was a bent push rod (#2). The repair shop made some repairs but asked if I'd been racing. (NO). I explained the last things I did with it. (Went over to the next town, then got gas, then came home, started it two days later (when we ran out of propane and I needed to go to the corner store to be able to finish cooking chicken) and the problem began upon starting the vehicle. Now, Fast foward to yesterday. Same EXACT precursory events --literally, (down to running out of propane while cooking chicken!). I went out and started up the jeep and we start hearing the sound that sounds all too familiar. Just like the last bent push rod. Why would this happen????? Ideas??
Why??? Bent push Rod..
- Thread starter JKs-XJ
- Start date
tardis454
New member
That's a tough call. There are many causes for bent pushrods.
Weak timing chain:
I've seen this a few times, but not on Jeep engines.
The chain gets weak, flexes, and the pushrods bend on the compression stroke.
My S-10 Blazer engine did this on a road trip, it sucked.
Loose rocker arms:
Common sense, loose parts = bent parts.
Weak valve springs:
Same as bad chain, only worse. If the springs are too weak to hold the valves shut, the compression from the piston will bend the pushrods.
Bogus lifter(s):
Common sense tells you if you have loose parts in your engine, you're likely to have bent parts down the road.
Bad head gasket:
Some cylinders will have much higher compression than others which causes blow back thru the intake(path of least resistance), and puts excess pressure on the valves.
Bad cylinder head:
Similar to bad head gasket, but isolated to the "bad" section of the head.
Piston(s) hitting valve:
Speaks for itself...
Weak timing chain:
I've seen this a few times, but not on Jeep engines.
The chain gets weak, flexes, and the pushrods bend on the compression stroke.
My S-10 Blazer engine did this on a road trip, it sucked.
Loose rocker arms:
Common sense, loose parts = bent parts.
Weak valve springs:
Same as bad chain, only worse. If the springs are too weak to hold the valves shut, the compression from the piston will bend the pushrods.
Bogus lifter(s):
Common sense tells you if you have loose parts in your engine, you're likely to have bent parts down the road.
Bad head gasket:
Some cylinders will have much higher compression than others which causes blow back thru the intake(path of least resistance), and puts excess pressure on the valves.
Bad cylinder head:
Similar to bad head gasket, but isolated to the "bad" section of the head.
Piston(s) hitting valve:
Speaks for itself...
Sparky-Watts
Banned
Along with all of what Tardis said, if it's the same pushrod, look for a foreign object in the cylinder. Had you done any work on the engine prior to this happening that exposed the intake to foreign objects? Generally, this will result in punching a hole in the top of the cylinder, but can also cause a bent pushrod, especially if the object gets stuck in between the valve and intake opening, holding the valve open and allowing the cylinder to impact the valve.
Sounds to me like you also need to either buy bigger propane tanks or turn down the heat!
Sounds to me like you also need to either buy bigger propane tanks or turn down the heat!
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