'07 4-cyl, replace timing chain without the sprockets?
 

Tomorrow I am replacing the; water pump, timing chain, chain tensioner, and chain guides, as a shotgun approach to the noise coming from the front of my engine. I however forgot to order the sprockets with the chain; is it OK to just replace the chain if the old sprocket/chain outer diameter is withing limits and looks good?

I am stationed in Germany so I cannot just go to Autozone to pick up parts as needed, and hence the shotgun approach to replacement. If the parts suppliers who ship to APO addresses had the oil pump and chain in stock I would be replacing those as well.

Ian

Noise from this engine is normal.

Might be the water pump, serpentine belt idler pulley or ? To check remove belt then run engine. Of course the water pump will not be operating but the engine will be OK for the brief time you check for noise.

As to the chain issue, in theory for chain drive systems the sprockets and chain should changed together. The issue is the assy has worn as a group and changing one component will cause all to now wear faster.

Ideally any sprocket the chain contacts should also be replaced.

However given your location and lack of access to the oil pump, etc unless you want to wait for what sprockets you can find suggest inspecting per the Toyota manual plus do a visual inspection of the teeth as shown in the link below:

Worn Roller Chain Sprockets Replacement

If the sprocket teeth have wear issues they should be replaced.

My guess? is if the chain system is the problem you will find worn guides, etc plus a stretched chain. Given the chain system has continuous oil lube, sprocket wear should be minimal.

If you are concerned about the cam sprocket wear take off the upper timing cover first and inspect, if bad can more easily reassemble engine to be able to drive car then order sprockets.

Chain/sprocket systems are common. As such the internet would have other hits on inspecting sprockets for wear.

Sorry for the delay, work is kicking my butt. I forgot to mention, I have a leak from my timing cover. Since the noise has been getting worse over the last 6 months, and the timing cover was coming off, I figured that I might as well service the timing chain assembly.

I did replace everything mentioned above. The water pump had a little play in it and the chain was within spec so I guess some of the noise was the pump. However in the last few days the alternator has been getting louder and the pulley had a slight wobble when I checked it while off the car.

As long as it holds out for the next 2-3 weeks it takes to get parts out here all will be fine.

Now I need to replace the vacuum hoses; one cracked during the maintenance.

The good news that happiness is only a "circle and three lines" away.

For vacuum hoses try a local auto shop as they are metric in size.

Otherwise use a caliper to measure the ID, should be 3, 4, 6, 8, 10mm, etc depending on the hose. The smaller hoses appear to be 4 mm.