got a new engine noise, what might it be???

[DaOne]

when the car idles it is not there
when i accerlate it is not there
when i slow down it is not there

but when i am driving and i press the accerlater lightly i get a tappin noise, i notice it the most between 3 and 4.5k reves, it feels like it does it when you match the reves with the engine speed, with out making the engine work, ie you set the engine reves to the same speed that the engine is going when the car is moving.

could this be the bottom end on its way out?

 

[Fast Guy]

ie you set the engine reves to the same speed that the engine is going when the car is moving.

The engine revs will always be the same speed as the engine:doh: :lol:


Does it do it if you blip the throttle to around that rpm and then lift off? (when stationary)

 

[DaOne]

no, i mean , when you drive along, just using the power enough to keep you going

 

[antgtir]

If it was the bottom end then i would have thought it would be doing it all the time i.e. when accelerating decelerating etc etc. Have you had a listen when someone else revs the engine to the 3.5 - 4k if its a metal noise from the gearbox etc??

Ant.

 

[PaulB]

just a picky sod !!! lol

 

[DaOne]

got a feelin thats it gonna be somethin bad :-(

 

[AJ4]

bottom end usually knocks under load, ie low speed + open throttle + too low a gear.

probably just a heat shield rattling. Any loss in performance ? If not, just turn your stereo up louder

 

[DaOne]

no performance loss, just a knocking sound, it gets faster as the engine goes faster. doesnt sound right

 

[AJ4]

exhaust hitting something ? If it was anything serious it would hurt performance. The fact that it happens at low rpm and low load, probably not the engine. Possibly gearbox, but once again you usually only notice these things at higher rpm / load.

just wait till something breaks and then fix it, if its something knacked then you'll have to change it at some point anyway

 

[EVOBAD]

could it be clutch realease bearing, they tend 2 do this ,put car in gear hold clutch down then see if it taps if so gearbox has 2 come offfff

 

[DaOne]

could be, but sounds more like engine than gear box/clutch

 

[EVOBAD]

as stated mate if it was engine it would be ther all the time ,hav u looked at oil presure guage in car wher does pin sit does it rise 2about 4 when u give it some

 

[Fast Guy]

Rod knocks are loudest at higher speeds (over 2500 RPM) Feathering the gas pedal may result in a distinctive back rattle between 2500 and 3500 RPMs.
Bad rod knocks may double knock if enough rod bearing material has been worn away allowing the piston to whack the cylinder head in addition to the big end of the connecting rod banging on the crankshaft rod journal. It will sound like a hard metallic knock (rod) with an alternating and somewhat muffled aluminum (piston) klock sound.

.

 

[DaOne]

what is the best thine to do/ who to see to find out what it is etc.

i live in cambridge