Clunking/Banging sound on startup

[gogoboygareth]

Hi all,

It's been a long time since I posted here.... from when I first bought my Commodore VXII with 20k on the clock.

I've now hit 190k, and I'm starting to feel that my engine is wearing out!

Basically, on first startup in the morning, sometimes the engine will make a banging sound for 5 seconds until the oil circulates. It's not a ticking sound (i.e. from the head), it sounds a bit lower & louder than that.

I'm now using 20W50 oil - used to use 10W30, but the engine started to use a bit of oil.

So.... is it just because of the oil, or is my engine about to blow up?

It doesn't do it every morning - I've been trying to make a video of it over the past few days to show my mechanic, but it hasn't done it for the past two days.

[garywg]

I would be thinking (and hoping) that maybe the oil is too thick.

[pablo]

My VT had simular sounds, but not always, on start up. Turned out to be the sump touching the cross member due to the sagging of the mounts.
Tho, mine wasn't exactly a "banging" sound, only a deep vibrating rumble.
A 6mm packer under each mount fixed it!

You are not using cheap filters with no anti-drain back valve in them, are you?

Pablo

[gogoboygareth]

Well my mechanic only recently changed to thicker oil, and he said it was probably just the fact the pump has to work harder to circulate the oil... but I'm concerned that this will cause damage. It only does it during startup, and only in the mornings (i.e. if the car has been sitting there for 8+ hours etc), but it doesn't do it all the time.

But because it only does for me at home, my mechanic hasn't been able to see (well, hear) it for himself, so he can't give me a definite answer. I really need to get it recorded on my camera.

It's not the mounts, well it shouldn't be, as I have the front engine mounts replaced a few months back as the sump was in fact hitting the cross member.

I use Pure One oil filters....

[gogoboygareth]

I'm really starting to think it's the oil being a bit too thick. I remember the mechanic talking about moving to a thicker oil, he mentioned 20W50, but the actual invoice just says "60W" (they use valvoline)... so I guess I have 20W60? (if that exists)

The noise hasn't happened at all now that I've been starting work a bit later in the morning, and the weather has been warmer. It *only* does it when it's cold outside, and the car hasn't been used for 8 hours or so.

So.... I will try changing the oil and seeing what happens. HPR 10W50, or 15W60?

This is a VX Series 2 (2002) with 190,000km's on the clock.... most of them are highway km's though.

[fitz_vt]

have you had a compression test done on your engine??
if you have please post the compression test results on here.
try changing the oil to the recomended oil in the owners manual..... and see if that works remember to get the right grade of oil for your vehicle!!!

[seannatt]

maybe oil pump not taking up i would get it looked at, will kill your motor..

[gogoboygareth]

No, I haven't had a compression test done....

You could be right about the oil pump, but I think the pump itself is working, it's just that the current oil is slightly too thick when cold, so the pump takes a few seconds longer to get the oil circulating properly.

I supsect when I put it back to a thinner oil it'll fix it completely.... would there be some kind of warning light on pump failure? This would be a lack of oil pressure and the light on the dash would come on though?

[fitz_vt]

No, I haven't had a compression test done....

You could be right about the oil pump, but I think the pump itself is working, it's just that the current oil is slightly too thick when cold, so the pump takes a few seconds longer to get the oil circulating properly.

I supsect when I put it back to a thinner oil it'll fix it completely.... would there be some kind of warning light on pump failure? This would be a lack of oil pressure and the light on the dash would come on though?

could be your compression Be too low, have you fitted a larger exhaust to your vehicle?

also others have raised a vaild point with the oil pump your lights may not necessarily come on because the sensors may be shot up.... but if your oil is too thick it could be... another thing it could be your engine mounts (sump touching the cross member , radius rod bushes (although it would happen more with turning)
there is all sorts of things just put some thinner oil in and see if that does the trick if not ... there is something else wrong