Locked up DOHC 3.4

[BumpRacerX.com]

My 3.4 stalled yesterday and wouldn't crank over afterwards, even though the battery and starter are good. Pulled the plugs, 3 of them were oil soaked well up into the boots. What would cause oil to be built up that much in the cylinders? Even with all 6 plugs pulled, the engine will barely roll over 4 or 5 times, and then lock back up. Wait 10 minutes or so and you can repeat the process.

What caused this? I'm already figuring the engine is shot, but I'm just curious as to what caused the problem to begin with.

[Dave96z34]

What did you hear? pull the plugs and try to rotate the crank with a breaker bar. You may have broke a rod or piston.

[pocket-rocket]

Before I bought the 92, Nick had an oil pump go bad, so the 92 got a new engine under warranty at 30k miles.

[BumpRacerX.com]

What did you hear? pull the plugs and try to rotate the crank with a breaker bar. You may have broke a rod or piston.

Hard to describe, I may record it later and post it on here (the sound). Really weird that the starter will get 3 or 4 rotations before everything locks up again.

What would cause that kind of an oil buildup in the cylinders? I understand bad rings will do that, but if it was just rings, wouldn't that oil drain back into the crank eventually?

[jman093]

If there's oil in the boots, the spark plug tube seals are leaking. It may cause a misfire and ruin your plug wires, but won't cause a sudden breakdown.

[BumpRacerX.com]

This is what 3 of the plugs looked like. The boots were soaked up about halfway. You can see all the oil that was in the hole on my plug socket. I've played with a lot of engines, but never seen anything like this before.

[BumpRacerX.com]

Now I found a thread on another forum that this may be a valve cover/cam case leak that's coming in through the outside, not the other way around. If that's the case, my one loan symptom may be wrong. I think I'm gonna be a breaker bar and put it on the socket just for kicks and giggles to confirm she's locked up and the starter didn't just burn out.

[Joseph Upson]

My 3.4 stalled yesterday and wouldn't crank over afterwards, even though the battery and starter are good. Pulled the plugs, 3 of them were oil soaked well up into the boots. What would cause oil to be built up that much in the cylinders? Even with all 6 plugs pulled, the engine will barely roll over 4 or 5 times, and then lock back up. Wait 10 minutes or so and you can repeat the process.

What caused this? I'm already figuring the engine is shot, but I'm just curious as to what caused the problem to begin with.

I'm sure you checked it and forgot to mention it, but what did you find when you checked the oil level? I recall recently helping a young woman with a Saturn that stalled thinking it was the battery when she said it wouldn't crank. When I attempted to start it the engine cranked over about 2 times but didn't sound like the battery was the cause. Upon suspecting the engine had a timing chain I checked the oil level and sure enough it was dry. Interestingly a couple quarts of oil freed it up and it ran without a tick, not sure if it still is now.

[BumpRacerX.com]

I'm sure you checked it and forgot to mention it, but what did you find when you checked the oil level? I recall recently helping a young woman with a Saturn that stalled thinking it was the battery when she said it wouldn't crank. When I attempted to start it the engine cranked over about 2 times but didn't sound like the battery was the cause. Upon suspecting the engine had a timing chain I checked the oil level and sure enough it was dry. Interestingly a couple quarts of oil freed it up and it ran without a tick, not sure if it still is now.

Actually one of the first things we check, as we figured we would find some metal shavings in the oil. It's about a quart low and dirty, but otherwise fine.

Anybody know right off hand what size socket is needed to turn the engine at the crank?

[pocket-rocket]

I want to say 15mm or 18mm. I wouldn't doubt if it's the starter. My 91 has done what yours is doing, and it was the gasket between the heads and cam carriers. I do hope it isn't locked.

[jman093]

This is what 3 of the plugs looked like. The boots were soaked up about halfway. You can see all the oil that was in the hole on my plug socket. I've played with a lot of engines, but never seen anything like this before.

What happens when you unscrew the plug? All the oil in the tube runs down on the head of the plug like that. You see it all the time on OHC engines. That's exactly what my plugs looked looked like after taking it out before I changed my valve cover gasket and tube seals. It doesn't matter if tubes were soaked up halfway. I fixed a misfiring PT Cruiser 3 weeks ago with leaking tube seals. One was so bad it completely filled up the tube and oil was running out the top of the valve cover and down off the back of the engine.

[jmgtp]

I had the o-rings leak as well, and the oil ends up on the spark plug. It might be able to find its way through the threads to make the plug wet but to hydrolock the engine...that takes a lot of oil (or water!), or you have something more sinister going on. Pull all 6 plugs and crank the engine. If it still locks up your issue is not hydrolocking from excess oil in the cylinder.

[sspeedstreet]

I bought a locked up '92 LQ1 and when I asked about it on this forum, someone suggested I check the oil pan. Sure enough it was dented in right where the oil pickup is located. Run over anything recently?

[BumpRacerX.com]

I bought a locked up '92 LQ1 and when I asked about it on this forum, someone suggested I check the oil pan. Sure enough it was dented in right where the oil pickup is located. Run over anything recently?

Possible, will have to look.

Ok, here's where I'm at. I couldn't get the engine to crank over clockwise with a bar on it, so I rolled it backwards a little. Now it will roll over fine. Started it up, running on 5 cylinders and has a knock. Shut it down quick.

Is there an easy way to tell if it's lower end or upper end? Should I pull the cam carrier covers, or drop the oil pan first? When the motor locked up originally, it was bouncing off the rev limiter in first gear. I've got a couple of parts motors to pull from, so if I can avoid screwing anything else up, I'll junkyard this thing back together.

I think tomorrow I'm gonna pull the plugs out and see if I can see anything in any of the cylinders or if any of the plugs are mashed.

[jmgtp]

Spinning the dohc backwards is a bad idea because it allows the timing belt tensioner to take tension off the belt and could throw the cam timing off....but that sounds like the least of your issues.

Did I just read that your motor locked solid at 6500 rpm?! It went from 6500 rpm to 0 in the blink of an eye? I'm going to guess broken rod.

Since the DOHC doesn't have rocker arms or pushrods there isn't too much in the top end to make noise. It is pretty much limited to collapsed lifters (which make tap like sounds not knocks) or bent valves. If its knocking, running on 5 and locked solid at high rpm I think the bottom end is trashed.