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Matt, Mechanical Engineer
Category: Car
Satisfied Customers: 22893
Experience:  BEng hons Mech engineering, in auto industry 22 years
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topped up oil in smartcar,3 days later,serious knocking,sounds

Customer Question

topped up oil in smartcar,3 days later,serious knocking,sounds terrible
Submitted: 5 years ago.
Category: Car
Expert:  Matt replied 5 years ago.

do youy have any check engine or other fault lights on?
Customer: replied 5 years ago.

oil light came on once,didnt come on again,but i still put oil in and car was ok for three days,then it started knocking severely,sounds like a bag of spanners.garage are convinced its engine fault,they guessing big end or crank shaft

Expert:  Matt replied 5 years ago.
Hello Trish

a big knocking noise could well be a worn crank bearing and these engines have been known to do this so I'm afriad that is quite possible

I'd 1st suggest measuring the actual oil pressure with seperate mechanical gauge - this can be plumbed into the engine via the current pressure switch port - if you use a Tee piece you can keep the pressure switch plumbed in as well and so see if the low pressure light corresponds to a low pressure reading.

If you do have a low pressure reading and to turn on the light it will be very low about 5psi then replace the oil pump and ensure that the pump pickup in the sump hasn't come loose or is blocked

if hte oil pressure is OK and its still rattling then I'd suggest removing the sump to inspect the bearings on the no.4 big-end