Hello,

So I was driving on the freeway on New Years Day and I head a lout metal POP. I pulled over, got it towed (I had only had my Runner for a month), and parked it. So I thought it was a broken rod or something.

One month later I started a comnplete engine rebuild (first time). Last night while removing the spark plug wires out of the way I noticed #6 plug was completely out.

Could that explain the loud POP in the freeway? Sounded like a tire popping. Could that also explain the loud engine knocking? I've had situations where I forget to reconnect the wires and the engine shakes and misfires, but never knocking. But I have never forgotten to put a spark plug back in though.

So at this point I am wondering if I should put everything back together as it may just be a missing spark plug or continue with the rebuild due to the engine knocking that could NOT be a spark plug missing?

 

By the way, this is for a 1994 3.0 3VZE Engine. Has quite a bit of miles on it 260K, but at this point if I could patch it up and sale it, I would be better off. Only reason why I was rebuilding it was due to a complete loss I had already considered.

Thanks.

 

If you've already torn it down, I'd go ahead and do the rebuild with that many miles.

 

I haven't torn it all the way down. I've only removed the fan, radiator, disconnected some hoses, removed alternator, power steering, etc. Just small stuff in the front. Nothing major. If there was a high possibility that with new spark plugs it would not knock then I would put it back together to make a sale. Otherwise I would continue with a rebuild.

Cost wise I would rather not spend it on this engine. Only reason why I purchased this vehicle is because it had 146K miles. However the odometer was spun and turns out it has 260+K miles on it. Otherwise I would have never made the purchase.

 

I've heard of a few of these spark plug blow outs with the 5VZFE but this is the first 3VZE. IIRC sometimes it damages the threads in the head. It always makes lots of noise and sounds like the engine blew. I'd carefully try to replace the plug (use copper anti-seize) and see how it runs.

 

Well I finally had some time last night and I managed to thread cyl #5 spark plug (end of engine block closer to the firewall on the pass side). I took a close up picture since I can't stick my head in there and no damage is obvious. So after the picture I tried to install and it did with no issues.

After further investigation It appeared that I had about 6+ quarts of oil which "could" explain the high pressure that made this spark plug pop out.

However I am stopping the rebuild since I haven't gone too far and do a leak down test to make sure all is well. If yes, I am saving my money and buying something that is NOT a 3vze although this engine made it to 260k+ which not many engines do (including Jeep's I6). Only reason why I want something different is the lack of power on this 145HP 3.slow.