Cold start knock/ oil light

[Anonymous]

IF i start my car when engine is cold my oil light stays on for few secs then goes off ,during this short time i hear engine knock which stops as soon as oil light goes out.
Can anything be done to stop this or is it normal ? My engine has just been rebuilt with new oil pump so oil pressure shouldn't be a problem .

 

[gtiroz]

totally normal,
BUT your oil viscosity has a major effect on this...
(thicker oil takes longer to start flowing)

what rating is the oil you are using?

 

[Anonymous]

Castrol 20\50 is in right now but i normally use Castrol 15/40

 

[Fast Guy]

Shalom, I'd only expect to get knocking with with the oil light on an engine that's abit worn inside, main or big end bearings more likely.

This engine has just been rebuilt so it should be ok, but I guess it's possible the bearing clearances are just a little too big.

Try a different oil ans see if it makes a difference.

Abit of piston slap would be nothing to worry about, but I would expect that to stop when the engine warms up abit, long after the oil light goes out, so I don't think that is your noise.

I'd be tempted to run it and just make sure it doesn't get any worse.

Did they do an oil change very shortly after the rebuild? (assuming you had a rebore? as often a thinner oil is used for this short period)

 

[J-GTi-R]

The problem is it is too easy to get confused with the usual timing chain rattle on start-up, which is normal.

Mine knocks a bit, but the oil light certainly doesn't stay on for a few seconds, but I use 10W-60 so it could be oil, it could be a problem with the big end bearings. A mate's car died a big end bearing death and that knocked like mad on start-up before it died.

 

[Anonymous]

I'll try a thinner oil tomorrow, maybe the Castrol 15\40 and see what happens.
The mechanic plastic guaged the crank and all mains and big end bearing clearances were with in spec. I used to get noise b4 rebuild ,only i lasted for shorter period of time .

 

[J-GTi-R]

Another thing it could be is the cam chain is tensioned by hydraulic tensioners and sometimes these take a while to pressurise, which causes the knocking to go on for longer than normal.

 

[Anonymous]

Changed oil and it has improved alot,,not as noisy on start up .
But i got another problem yesterday !
I noticed oil dripping from around sump and after inspection my oil pump housig (front cover) i saw it has a crack .I'm looking now for replacement housing that i can transfer my new oil pump internals to. Anyone have a spare ? 8)