Mi16 Oil Pressure Problem ...a Bit Strange Situation

[Goran 3]

hey

just properly rebuilt a mi16 (1.9) engine with new all new bearings ect.

 

the story goes like this

the oil pressure is way too low (on cold start 1500rpm is 3 bar), and as the engine gets warm it looses presure even more of course.

 

so i tried to change the sensors and it didnt help ( the stop light comes on and it falls way under 1 bar when it warms up)

i checked the oil pump and it's in ok condition, the valve isn't stuck, and the spring is ok

 

anyone any ideas? i'm out off... could the piston oil spray bars be the problem maybe, or anything else? the crank was messured and it was in good condition, so the standard bearings were fitted

[Vili 18]

If the piston spray bars are on their place and the all the bearing tolerances are ok, next I would check if the camshaft spray bar is fitted properly with the O-rings. If everything seems to be correct, I would try with a new oil pump. Because the engine is either "leaking" the oil or the pump doesn't have enough pumping capacity.

 

Or actually you should probably measure the oil pressure with a proper oil pressure meter, because the one on the instrument panel is commonly very inaccurate.

[rallysteve 22]

Is the crank pulley bolt correctly tightened as the oil pump sprocket is only friction driven. If the bolt is not tight the sprocket could be slipping.

 

Steve

[Anthony 1,003]

Or actually you should probably measure the oil pressure with a proper oil pressure meter, because the one on the instrument panel is commonly very inaccurate.

Whilst the standard gauge/sender isn't particularly accuate. if the gauge is reading low and the warning light is on then it's pretty certain you have an genuine oil pressure issue. Of course, there's no harm in verifying it with a proper mechanical gauge, but in this instance I don't think that it's needed.

 

Does the oil pressure pick up and climb to expected levels (~5 bar hot) when you increase the revs, or is it low throughout the rev range?

 

Well worth checking the crank pulley bolt as mentioned above, as that being loose will result in low/no oil pressure.

[Goran 3]

I'm reading a low pressure, and the light comes on, since those are seperate indicators that let me to think that there really is a oil pressure problem ... I eaven changed the indicator, as a desperate try... It didn't make any difference.

The pulley is thightened as it should be acording to AutoData... When i went to replace the oil pump, i tried to turn the chain with my hands as hard as i could to see if it was slipping, but i couldn't make it slip... I dont know if I could apply enough power to make it slip, but i thought that the oil pump is really easy to turn, so the pulley would had to be really loose to make it slip (correct me if i'm wrong)...

Are those piston sprayers spraying all the time or just at specific pressure

I'm runing out of ideas, and it's breaking my heart to take the engine out of the car, and take it apart again, because i'm sceared i will not find what us wrong. :-(

[dcc 855]

Do these not use a woodruff key on the crank for the oil pump?

 

Although if it started to spin i doubt you'd make ANY pressure at all...

 

uprating the pump would only help to disguise the problem if there is something worse there...

[Goran 3]

sorry i forgot to mention, when i took off the pump i put 2 milimeter plates between the valve and the spring just to see what will happen, and it made no difference at all

[Alastairh 47]

What oil, oil filter and oil pump are you using?

 

Al

[Goran 3]

5w-40, oem peugeot/citroen ...oem oil pump

[Rob Thomson 6]

The spray bars have ball valves that only open above a certain pressure.

 

Are those piston sprayers spraying all the time or just at specific pressure

[Miles 331 1 Cars]

They quite often fail, But even if stuck open the pressure should not be effected

[calvinhorse 870]

I left my camshaft spray bar out once and it had the same symptoms

[kyepan 291]

when I rebuilt my mi both the piston oil spray bars were totally blocked with crap, and took a while to free up.

[Koos Agtereek 0]

Hi,

I had exactly the same problem, after rebuilding my MI16 / RS Hybrid engine, after replacing oilpump for an RFS item, and checking all the suggestions above, I measured the cranckshaft main bearing diameter, it turned out that the cranckshaft had been ground before and that I should have put oversized bearings in. After replacing these the oil pressure was fine.

[Goran 3]

Just to round this up... I'm an idiot... Forgot to put in camshaft spray bar... Now the pressure seems to be fine...

 

 

This is when cold...

When it warms up oil to 90 it's on the lowest mark. I think that's about 1 bar on 1000rpm

That ok?

 

Btw. Thank you guys for your ideas, really helped me out not to take the engine apart again

 

Goran

Edited January 6, 2013 by Goran

[calvinhorse 870]

YES!!! I love being right!!

[2052NV 24]

haha brilliant!