Hi all,

 

seems that I am asking a new question each week in general mechanical.

 

So I have done an oil change on my smallport 4age. The motor is from

a wreckers but goes very hard, from what I gather the odometer said on the wrecker

car the engine has done anywhere upto 300,000. I have suspicions it has been rebuilt at some stage.

 

Changed to fully symthetic mobil 1, (my mate kept talking it up) so the car runs fine but oil pressure is all over the place

on cold start the oil pressure shoots up to 6 bar (87 psi) and with the slightest tap of the accelerator the pressure raises even higher.

once the car is warm it stabilises a lot and goes down to around 3.7 bar. But then if I give it a flogging it stays on 3.7 and won't move

I don't know whether it's good or bad. And I can't come to a conclusion on the health of the engine because if it can hold 6-7 bar of oil pressure

I gather that's not too bad? Should I bother changing oil to something thicker, and some people say once you'v gone full symthetic

don't go back to mineral or semi. ( the oil has only been in for 2 days).

 

Any help is much appreciated cheers.

what grade is the oil?

i run semi synthetic 15-40 in mine and my oil pressure is always stable, always is a bit lower at idle then under acceleration but that's how it should be.

then again i change it every 5000 km.

only thing i can suggest is to change and save the oil and see if there is any difference, better that then creating a leak with too thin oil or burning it and glazing the bores.

thats just a suggestion

what grade is the oil?

i run semi synthetic 15-40 in mine and my oil pressure is always stable, always is a bit lower at idle then under acceleration but that's how it should be.

then again i change it every 5000 km.

only thing i can suggest is to change and save the oil and see if there is any difference, better that then creating a leak with too thin oil or burning it and glazing the bores.

thats just a suggestion

 

it's 5w50. Cheers for the info, will consider something like that 15-40, I've herd that the whole oil leaking from the motor because it's too thin is a load of bs from some people, but i am inclined to

agree because oils like mobile one have all sorts of additives like gasket softener and things like that that prevent oil from leaking badly regardless of how thin they are.

it doesn't matter how much additive shit your oil has if the seals are hard and stuffed nothing is going to change that. plus if you are talking about increased oil pressure and old seals something is going to give way. just my opinion as i see this every day

it doesn't matter how much additive shit your oil has if the seals are hard and stuffed nothing is going to change that. plus if you are talking about increased oil pressure and old seals something is going to give way. just my opinion as i see this every day

 

ok cheers, think i might do another oil change, waste of money that was, never listen to your mates haha.

if the oil hasnt done much, eg 3 days work, keep it and use it later on something else

Would have thought 15W would be too thick and you'd have problems with the lifters bleeding down. Might be fine in the heat but once winter comes could be an issue. 15W is too thick for the Hyundai Excel.

If the motor's got a bit of age a fully synthetic 10-60W would work well, otherwise a 10-50W would work.

I'd suggest the erratic oil pressure guage is exactly that... an erratic oil pressure guage. Or there's some crap floating around the relief valve of the oil pump.