Toyota Engine Knock

[JCook5003]

Ok Guys-

I'm at the end of my chain trying to figure what the hell the noise coming out of my truck is.

It's a 94 22RE 5 Spd 155K miles..........

It has a terrible knock when it's cold that seems to come and go when it gets hot. I pulled the valve cover checked the valves they are good, and it has excellent oil pressure. I also check the timing chain and guides they look good as well. Not to mention it wasnt doing this when I bought the truck approx. 2 months ago from Stinson.

I was thinking a rod bearing but it should knock all the time if that were the case, then I though wrist pin, but again it seems as though it would knock all the time.

I just dont know what else to check or how to further diagnose the problem. Any suggestions? The truck has been kept in excellent condition I just cant imagine an engine problem so early in it's life.

[TerryD]

Sounds like piston cluck. The piston shrinks when its cold and due to it being aluminum, expands more/faster than the steel and when it gets hot take up the slack and stops.

[JCook5003]

If it were the piston why would it have only started recently, wouldnt that have been an on going problem.

[TerryD]

Possibly, then there's the point that it could have only gotten bad enough that you noticed it lately. Have you checked the timing chain to make sure its not flopping around. How about front/rear play in the crank to see if its the thrust's worn, letting the crank hit the block? I thought the 4.0L was knocking in my XJ, turned out it was a bell-housing vent tube that come up next to the engine had come loose and was tapping the firewall when the motor was running. Get you a mechanics stethoscope and start looking.

[JCook5003]

What's everyone think of a timing chain tensioner? Works sometime doesnt work others and is allowing the timing chain to smack the timing cover?

Opinions? My local garage guy says thats what comes to his mind first?

[JCaldwell]

Is it a knock or a ticking sound? Does it do it all the time or at idle? It is prob due for a timing chain,tensioner and sprockets..

[JCook5003]

It sounds like a rod bearing or wrist pin, but it only does it sometimes, mostly when cold and stops or really quiets down when it gets warm. It's very sporatic about the way it comes and goes. But the general pattern is that it's worst when the motor is cold and then stops as it gets warm.

But the thing is it's not all the time, only sometimes.

[Stinson]

A knocking sound tells me its not the timing chain. The chain sounds like a flutter usually. When the guides went in my 22r it sounded like a leaf in the fan at certain RPMs. The timing chain tensioner could be gummed up and work occasionally, but I don't think you would get a knock. When I had the valve cover off the guides looked to be in good shape and I didn't see any strange wear patterns.

You need to pinpoint the sound when it does it. If it does it cold grab a garden hose and listen and see if you can tell where its coming from. Sorry about that man.....only noise I ever heard out of it was timing chain rattle at start up. Good luck and let me know if I can help. Cya Stinson

[JCook5003]

Stinson - Definatly nothing to be sorry about, it wasnt doing it when I bought it from you. But if you feel that bad about it you could buy me an LC Engineering Stroker to put in it.

Anyway I'll try to pinpoint it......I'll listen with a long cardboard tube and see if I can find out where it's coming from.

That's what's odd also, the guides, and chain both looked good yesterday when I had the valve cover off. But then again no way to really check the tensioner.

[TerryD]

I still think its piston cluck. My Cavalier did it like you describe. When it was cold, that thing hammered. As the motor warmed up, it went away. It was worse in winter time as the piston contracted more due to the increased cold. Didn't do it as bad in the summer. It would start really showing up around fall and get really bad around November when the weather got more constantly cold. Then it would gradually let up as spring apporached and not hardly be noticeable in summer. As the motor wore more, it got to the point it did it year round, but was still worse in the winter.

[shmoken875]

I still think its piston cluck. My Cavalier did it like you describe. When it was cold, that thing hammered. As the motor warmed up, it went away. It was worse in winter time as the piston contracted more due to the increased cold. Didn't do it as bad in the summer. It would start really showing up around fall and get really bad around November when the weather got more constantly cold. Then it would gradually let up as spring apporached and not hardly be noticeable in summer. As the motor wore more, it got to the point it did it year round, but was still worse in the winter.

my moms Tahoe 5.3 has piston slap that's more noticeable at start up and in the cold months too.

[alk1174]

I had the rod bearings go in my 22r due to a poor rebuild from the PO. It was quiet at first and slowly got worse and was somewhat sporadic at first. I came to the conclusion the PO had done a bad rebuild so I drove it till it started losing oil presssure and power. When I pulled the oil pan to swap motors there were lots of metal particles in the bottom. Pulling the oil pan may be an easy check if its not too hard to get to on the ifs.

[Stinson]

that darn IFS is in the way, time for a SA S

[JCaldwell]

Rod bearing would do it all the time,if its a rod bearing u can really hear it under a load..wrist pin usually does it in the throttle higher RPM but that is still up in the air...Stinson is right about the timing chain it usually has its own sound and usually does it during start up.. What does it do reving the motor? Does the truck run good other than that?

[JCaldwell]

You can get that oil pan out if take the front skid,steering stabilizer off,motor mount bolts then jack the motor up as far as u can get it without hurting anything it will come out but its still not fun on IFS! Good luck