4.0 engine drops number 6 cyl,

first off,im not good at the computer,sorry it'll show. I have an 05 tacoma 4x4quad cab sport.Ihave 172000 mileson it and take very good care of it. One week ago i left t a stop sign pullimg away very easy and hear a bang in the engine compartment,the truck goes to half power and the check engine light come's right away. Number 6 cyl. has an 70 percent air loss but cant see a darn thing in the borescope test.Im stunned. the engine was so clean that it looked like i just changed the oil. Any help please? thanx jay.

 

Headgasket?

 

To me a bang sound probably means a bent valve or broken connecting rod. With that low compression you definitely have a problem. I'd pull the head and/or oil pan and have a look. Borescopes work great up to a point. Sometimes you just have to take stuff apart to see it.

 

Thanks steve, but all the compression test air loss goes down the bottom of the crankcase. dahm man i love my truck!

 

Sounds like rings or a cracked piston. The good thing is that these engines are still in production, so you should be able to find a low mileage one out of a wrecked truck. That's probably your best bet unless you've got the time to pull your engine apart and inspect it. With the design of the engine block, you are going to be SOL if there is damage to the cylinder wall, not to mention the cost of fully rebuilding the existing engine.

Whatever you do, stay away from parts store engines. I've sold them, you don't want one. My first choice would be a brand new crate engine, fully assembled (don't thing Toyota even does that), second would be low mileage salvaged engine, third would be a rebuild by a local, competent machine shop (hard to confirm reliability if you don't have previous experience with them).

Good luck, tough place to be.

 

Thank you,im just baffled,my truck is super clean. People still ask me if it's brand new! I still have a 1883 long bed 4x4 at home with 742000 original miles. Same care all it's life.???????????

 

could you elaborate on this?

 

From everything I have read on here, the 4.0 is an aluminum block with a paper thin iron liner in each bore. I believe the term is "spiney liner", so that they can't be pressed out and replaced. Some of the posts here about high performance engine builds have shown the block can be bored out and resleeved, but it's not a standard, stock rebuild type of thing. It looks like big dollar, go fast stuff. It's not like the 3.4 v6 with an iron block that can be easily rebored for oversized pistons.

The OP sounds like his goal would be to get his stock engine back to stock running condition. If there's damage to the stock block, I don't see that being economical compared to starting over with an undamaged block.

Edit: Here's a link: http://www.toyotatundraforum.com/pdf/1GRFE Engine4.0.pdf See page EG80 where it talks about the cylinder liners.

 

interesting read, thank you. i did not know any of that.