engine noise

[jeffmsmith]

When I start my engine there is a knock that sounds like a diesel engine. It is really annoying at low RPM and you can hear it inside the car but once I get up to speed on the highway the sound seems to disappear from what I can hear on the inside. Does this sound like the belt tensioner pulley problem that a lot of people seem to be having or does it sound like I might be throwing a rod? This is on my wife’s car and I don’t really know how long it has been making this noise but I have a feeling it might be going on a month now. Is it safe to put the belt off and start the engine to rule out the thrown rod thought I have? Any tips on finding out what this might be would really help.

[keithvibe]

need a bit more info, pleaseyear?model?engine type?how many miles?Any mods done to the car?Possible sound clip??Is it more like a Ticking sound?

[BlueCrush]

Is it a marble in the cup sound? A quick easy way to tell if it is the belt tensioner pulley is, with the engine off and cold, reach down and grab the belt and wiggle it hear the tensioner. You'll know right away if the tensioner is the culprit. You should hear a similar sound as when the engine is at idle, if it is.

[jeffmsmith]

no engine modsits a 2006 with 1.8 and about 40,000 on it.Can't pull on the belt right now because the car is gone but how hard do I have to pull on it. I kind of tried it last night but I didn't hear anything.

[ned23]

Could be that one of your pistons is "missing" when the car is cold. The solution to that is to first change your wires, then your plugs. That could also be caused by a leaky injector that is flooding one of the cylinders with fuel. As the car warms up the extra fuel is evacuated. You can determine that by having your oil tested to see if there is gasoline in it. Again, without hearing the sound it's hard to tell.