I have a question I was checking the tension on the timing belt in my 95 Toyota corolla 1.6 l and it seems sort of slack.I was wondering if you think that maybe that this looseness could be why my valve train could be making noise. And also why at times it seems to be lacking power. Hoping for a response John from Canada
A loose timing belt can cause the timing to slip, both ignition and valve timing. It won't cause noise in the valvetrain, unless it's slipped enough to be causing the pistons to be slapping the valves.
A noisy valvetrain is usually caused by valves that need adjusting, or inadequate lubrication of the valvetrain. How long has it been since you changed the oil, and what weight do you specify/use?
Pull the timing cover and verify that the timing marks line up properly. Make sure the belt tension is correct (.2-.24 inches of deflection, max, with 4.4lbs of pressure applied). If not, re-tension the belt if you can. Otherwise replace the belt and tension it properly.
June, 26, 2011 AT 3:49 AM
I recently changed the oil and I used the manufacturers specification 5w30 I started the car one day and I noticed a noise coming from the engine compartment and I don't think its the valve train but I think it might be the alternator or water pump. The drive belts haven't been changed in a while and 50000 ks at least. It sounds at times like its bearings or something. Thanks for the previous answer. John
June, 26, 2011 AT 4:09 AM
Uh, yeah. 50K. Those belts are screaming for a change.
If you've got a long extension, or other solid piece of metal, start the car and hold it against the valve cover with the upper end against your ear. Listen carefully for clicking, clattering or tapping sounds.
Next hold it against the alternator. Does the sound you heard get louder?
Next, move it as close to the water pump as you can get it and listen.
One of these will have a sound that duplicates what you're hearing through the air. It will identify the offending component.
5w30 is perfect.
Please come back and let us know what you find.
June, 26, 2011 AT 11:29 AM
Its actually funny you said that about the using the long piece of metal against the ear.I was working with some mechanics and one of them said to use a stethoscope and I got one and I noticed the sound was not coming from the valve train. He also said too that it could be the drive belts. How do I do a pressure test on oil pump. And I was wondering if it could be the crank shaft bearings.
June, 26, 2011 AT 5:23 PM
It could be the bearings, but usually that'll be a knocking type sound.
Some part stores have tool loaner/rental programs. See if one near you has an oil pressure tester. Otherwise, you can install a $10 gauge. Or, remove the oil pressure sending unit and the coil wire, and then crank the engine over while watching the sending unit orifice for oil flow. BUT, that method won't tel you how much pressure there is. For that, you'll need a gauge.