Cadillac Repair: 2000 Cadillac Engine Noise, cadillac deville, 2000 cadillac deville

Question
Our mechanic said it isn't a tick but because of the tone, he is calling it a knock.
-------------------------

Followup To

Question -
We just recently purchased a 2000 Cadillac Deville with 60000 km on it.  It was working perfectly and loved it.  Parked one night, the next day started it and extremely loud knock.  We immediately turned car off and checked the oil - it had only gone 3800 km since oil change - and it said add, so added some.  Restarted the car and the knock (ticking sound) was still there although significantly quieter.  We have been told it is probably carbon buildup but wondering if that can happen so suddenly that we have this ticking sound suddenly with no noise prior?  Can you give any insight?  With low kms and good shape - it is hard to believe that the engine is needing significant work yet...

Answer -
There is a major difference between a KNOCKING and a TICKING sound. You will have to get a tech to listen to it.

Answer
GM has a product out called carbon buster or you can buy it or a similar product in any auto parts store.

What you do is run the engine up to normal operating temperature and pour in approx 1/3 to 1/2 of the contents of the can into the throttle body real fast until it stalls out the engine.

Turn the car OFF and let it sit overnight. the next morning it will be extremly hard to start but it will eventually start and get it back up to normal operating temperature and raise the idle speed up to about 1500 rpm's and SLOWLY pour the rest of the contents of the can into the throttle body. You do NOT want to stall the engine. Once the product is all gone keep running the engine until all the smoke clears from the exhaust pipe and see if your knock is gone.

This stuff is supposed to melt the carbon deposits off the top of the pistons.

It's worth a try.