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3.4 engine problems?


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Posted

hey everyone...

 

ever since i've had my z34 (about a year and a half now) it has made a bit of a grinding/whining sound, most obvious when accelerating. is this sound just a characteristic of the cars (or engines), or do you think there is a problem somewhere?

 

i had a mechanic look at my car today and he said that it is most likely a camshaft problem or something of the sort.

 

thanks for any opinions.

Posted

Does the engine run bad or rough idle or burn oil, does the exhaust smell of gas, does it get bad MPG? Just curious, these things usually help in a diagnosis.

 

Robby

Posted
Does the engine run bad or rough idle or burn oil, does the exhaust smell of gas, does it get bad MPG?

 

tranny fluid level or power steering fluid level?

 

the engine runs good. i check the fluids on a regular basis and all seem to be fine. they also informed me that there is a minor oil leak today.

Posted

the whining maybe your alternator......mine made a whining, sound like a suprercharger before it went out. Im just kinda guessin on that though. Somebody who knows more about LQ1s than me, would the cam belts or gears be causing this?? Again, just shootin at some things here.

 

Robby

Posted

The reason I asked if the timing belt was replaced recently is because the belt could be too tight(too much tension). So yes Robby1870 the belt can be a strong possibility!! :)

Posted

Oh yeah check your motor mounts too. Make sure those are in good shape and not twisting or flexing your drivetrain upon acceleration :) :)

Posted
The reason I asked if the timing belt was replaced recently is because the belt could be too tight(too much tension). So yes Robby1870 the belt can be a strong possibility!! :)

 

How would your timing belt have too much tension? The tensioner is spring actuated.

 

It could be your PS pump or you alternator. Take a long screw driver place it up against the pump while it is running (be careful you don't put it up against something moving) and put your ear up to the hanndle. You can also do that on your block near your water pump. If it doesn't sound like one of those I'd keep an eye out on your alternator.

 

And it wouldn't be a bad idea to take off your belt covers (8mm socket i think) and lok at your timing belt. As general maintance if you have not.

Posted
The reason I asked if the timing belt was replaced recently is because the belt could be too tight(too much tension). So yes Robby1870 the belt can be a strong possibility!! :)

 

Yeah I have heard if those belts are messed up, the motor will run weird and the problem is hard to track down, cuz the belts are like the last thing you think of when a motor is running bad. What if one is loose or torn? Would that cause a grinding?

 

Robby

Posted

If the spring inside any tensioner were to apply tension during certain engine RPM's due to belt stretch it should retract and keep a predetermined tension on the belt. regardless of RPM's. If the spring is worn out, it will not keep the right amount of tension on the belt. If the tensioner got stuck applying or retracting tension, It will cause your belt to make a whirring or whining sound. If you think the PS pump is at fault, take the cap off the pump res. and listen for any noise inside the res. As far as the grinding goes. The belt can cause grinding in rare cases. If the belt is too tight, you wont be able to build the hydrodynamic oil pressure between the bearing surfaces and journals on the camshafts causing metal to metal contact. All 5 of my cars have timing belts and two of them I change every three months regardless of mileage. (expensive motors)

Posted

Sounds like a little overkill, but its better than the people who don't change them.

Posted

Some people let their belts get as lose as a village whore. If the tensioner has gone bad you will see odd wear in the belt and it will probably look stretched or start to come off the cogs when you look at it.

Posted

interesting comparison. :lol2: :lol2: :lol2: :lol2: The tensioning spring itself probably isn't bad , but something has probably lodged somewhere causing it to stick

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