I was on my way back from vacation and the nav started to lose power. The vehicle did not shut off but could not go faster than 20 mph. It idled rough and it felt like I had lost compression. I took it to a shop and they tested the fuel pump...30 psi..I bought a new one and it tested 28psi..they connected the same (brand new gauge) to their truck and it registered 45psi...They insisted I had a defective pump but I took it to the dealership instead...mind you I was still 152 miles away from home...Dealership stated one of my cams is not turning so I will need to have the engine pulled out and have head work on one side. I called two mechanics that I have used before locally and they asked me if the dealership removed the valve cover yet..I explained to them they have not. So they asked how do they know the cam is locked. I asked the dealership and they stated with this tool they have to check for it...
My mechanics are stating that all I need is to have the cam replaced, fix busted valves and have it timed again...no need to have head work done and have the engine out and apart....

Can I just replace the cam, what do you all think?

 

I think you will have to be sure that the cam is the problem before you start tearing things down. Here is a senario. If the cam seized in the cam bore then the timing chain is almost surely broken as well. The cam bores will be burned beyond repair (unless bearings are installed after machining the cam bores). About a 99% chance the valves made contact with the pistons and they are damaged as well. Usually the reason a cam seizes is from lack of lubrication meaning the rest of the engine and bearings may be affected from poor lubrication. If you look into the cam cover oil fill hole while the engine is running you should be able to see if that side cam is turning a CID signal may give them info on the other side. Still I would remove the cam covers to make sure what you have here or a compression test will tell you. These engines will go into limp home mode if they overheat and this will give you some of the same symptoms you were getting as cyls start to shut down via the PCM. If the cam/cams are the problem then the cyl head will have to be removed to be repaired/replaced. No fixing damaged valves or burned cam without removing the head. If the pistons are damaged then the entire engine will have to come out. This is all assuming the dealer is correct in their diagnosis. Again just make sure you know what was taking place when this all happened because there are several other things that can cause this without it being catastrophic. Good luck.

 

thanks, I will have the other mechanic start looking into that...The stealership will not have the job as per my request...

 

I finally was able to pick up the Nav this past Friday...It turned out to be a broken timing chain..It was the smaller one on the driver side...Happy that no engine damage was done..



She runs great again!!!!