Chasing down a loud engine knock in a Land Cruiser
From time to time I do work on cars other than Mercedes Benz. Sometimes it is painful and in the process, it reminds me why I like working on Mercedes. So was the case when I took on working on a 1997 Toyota Land Cruiser with a loud engine knock. This knock piqued my interest because it sounded like it was moving around in the engine. At first, it sounded like something in the valve train. As we progressed with our diagnosis it sounded like it was a piston or wrist pin. When we finally removed the oil pan we realized it had to be something serious.
Watch the 5 part video series on youtube if you are interested in what we found: https://www.youtube.com/playlist?list=PLtRKk64pu2wq7Ch_1Uy7PwVADKefZytPN
What did I learn in the process?
- The cause of an engine knock can fool you. It may not be where you think you are hearing the noise.
- Don't assume anything when chasing an engine noise
- My strong dislike for silicone gasket maker was once again confirmed! ( Shame on Toyota )
- If you start hearing what you believe is an internal engine noise limit your driving until you find the source (if you care about the engine)
We had thought of fixing the engine by polishing the crank and replacing the rod bearing. All the other rod and main crank bearing surfaces were in good condition. But we found that the upper connecting rod was deformed and excessive contamination inside the crank, it became obvious the engine would have to be pulled and completely overhauled. The car was sold to someone who is planning to put a Cummins diesel engine in it. I was not sad to see this go down the road. It was one of the worst cars I have ever worked on. Don't believe it. Try changing the O2 sensors. Shame on Toyota for not using stainless fasteners. Try changing the fuel filter. And for some real fun try changing the front brake rotors. So you can also learn appreciation when working on other cars. :-)