Internal Engine Noises? HELP!!

[heather2308]

Hello.

Past 2 weeks I've been hearing a loud-ish thunk noise coming from under the hood. Sounds like a bad pulley (I've had one replaced before, sounded the same)

Sure enough - went to Canadian Tire last night, they said it was serpentine belt and tensioner pulley. Went in today to have it fixed.

30 minutes later - they tell me it's not what they said and I have an INTERNAL ENGINE NOISE. WHAT?! My heart was in my stomach and I almost threw up. Stressed out isn't even close to what I feel. He basically told me he thinks it's something to do with bearings and the car is driveable for about another 40,000k and then it'll need replaced (either the whole car, or I replace the engine)

The sound sounds like a bad pulley - that's the only way I can describe it. It gets a little faster as I accelerate and you can hear it from the time the car turns on to the time it turns off. I've looked up 'rod knock' noises and that sounds more like a deep tapping...that's not what I have. It's a deep thunk type of noise.

I'm taking it in to my dealer for a second opinion but I wanted to post here to see if his diagnoses makes sense?

This is way to stressful!

By the way, I have a 2004 Chevrolet Optra...as much as I wouldn't want to get rid of it - I don't think a complete engine overhaul is worth it. Sigh.

Any ideas/advice?

Thanks

 

[mattylad]

Whats the oil level like?

 

[heather2308]

Whats the oil level like?

I checked a few days ago and it was a little low - I'm due for an oil change right about now. However, I do have an oil leak so I get mine changed sooner rather than later. Oil seemed fine when I checked.

 

[heather2308]

Whats the oil level like?

I checked a few days ago and it was a little low - I'm due for an oil change right about now. However, I do have an oil leak so I get mine changed sooner rather than later. Oil seemed fine when I checked.

 

[Mursal]

Water pump?

Timing belt?

Get a second opinion with all due respect, from a proper small independent mechanic.

Where is the oil leak?

You don't mention make or model?

 

[lrobertz]

It could be a numerous of things inside the engine that could cause that type of noise, but If your oil level is quite low, it stands a chance it could be your big end shell bearings, it may sound bad, but these are here as a precaution to fail first before your con rod's do.

I suppose the only way to find out, is to drain oil off, take sump off and check if there are metal shavings lurking around in the bottom of your sump.

Hope this helps mate

 

[Burnerman]

Failure of any crankshaft bearings will throw up low oil pressure - which may cause the oil lamp on the dash to illuminate when the engine is hot and ticking over slowly....failing that, a reasonably equipped garage could attach a pressure gauge and compare the readings with the manufacturers recommendations.
Does your car have a dual mass flywheel?
40000k is a fair old mileage if the crank bearings are failing - I wonder where the mechanic gets that from?
John

 

[Crickleymal]

40000k is a fair old mileage if the crank bearings are failing - I wonder where the mechanic gets that from?
John

I did wonder about that myself. If true whatever it is doesn't qualify as remotely urgent.

I'd get a couple of other quotes myself before launching into anything expensive.

 

[Burnerman]

I've never had crank bearings fail in normal use since that dreadful Ford V4 - skinny shells and two journals on each crank pin....no wonder the crank flexed
John

 

[Mursal]

I think Audi still bolts 2 con-rods onto one journal, and they don't bend?

 

[Burnerman]

I can't comment, but I bet its a bloomin' huge crankshaft, with more than 3 main bearings to support it
John

 

[Peter.N.]

On the Perkins 4/108 engines with three main bearings the crank used to break if the timing was a bit advanced, had it happen to me several times, also once on a BMC 1500 diesel.

Peter