I am having 2006 santroLX,while starting my car,s self is making rotating and chattering noise but my car does,nt start.pls help

If it's a "squealing" sound - check the power steering fluid. If it's more of a grinding sound - then the wheel bearings were not properly "packed" with grease. Note - the grease needs to forced into the bearings by hand while rotating the bearings. I had a this problem myself when a "mechanic" just smeared some grease around the bearings.

The timing chain area also takes in the alternator and water pump. To isolate the source of the noise, use the old mechanics trick.

Place a 3 foot 1/4 inch brass rod against the flap at the opening of your ear and push until it closes. Place the other end of the rod against various engine components and listen. The noisy problem will conduct the noise up the rod to your ear and you can hear quite precisely where the problem is. Much safer than laying your ear all over a running engine.

You can also loosen the fan belt and run the engine without alternator or water pump (briefly) to see how that affects the problem. Chatter on start makes me think of starter and Bendix gear problems. Sounds like a 2 person diagnostic team to me; one to start the car and one to listen and probe.

Don't know if Subaru Forrester has an engine that has valve interference at piston Top Dead Center. If it is and the timing chain breaks, you are looking at major $$ to recover.

Well depending on the noise. If it makes a squeel, chatter, or grind thats the brakes. If it makes a nasty THUNK if you stop or accel hard or sometimes while your turning then I would say the ball joints. Changing them on a f150 is a pretty easy task either way.

The two symptoms you posted may or may not be related. I'd check the driveshaft and axle joints for any looseness or binding. (do this with the rear wheels hanging free in neutral, front wheels blocked)
The chattering may be an axle joint or the posi unit in the differential. Most times replacing the diff lube, (using posi additive) then making tight left and right circles will free the clutch packs.
Difficult to diagnose noises online. If you have any problems finding the source, have an experienced tech look at it,,,You still have the option of actually doing the work itself.

What size engine?

Hey, well 1st. If the engine light came on I would scan 4 error codes or have any auto shops scan it 4 you so you can clearly know where to start and how serious is it. As if it died on ya a few times already, it may b somthing big and u not doing yr self any favers by keep pushing that cas., a specialy if thats the 1 that feeds you At the moment ????. Hope that helps . G/luck .??.. Tony

use an engine flush when changing oil/filter use only 10/40 semi synthetic oil(change every 10k)top end chatter occurs when engine is cold/oil not up to followers,but should stop about 30 secs after starting engine.there ARE NO adjustments AT ALL.if chattering persists,then top end rebuild req.
the person who told you about "rockers"should learn about self adjusting valve followers....

That's a tough one...because there are too many factors/variables. How you drive, how the roads are, potholes, etc.. But normally, you should get at least 40k-60k. And that's conservative. My 1999 Taurus has the original struts at 140K. If the strut makes noise, then maybe it has been damaged from a one time pothole, or curb, etc.. If so, the strut has lost it's gas/oil and it will start to chatter. Hope this helps a little.

check silencer or exhaust support....

sound like disc brakes.