deza3000

Hey guys, im really worried about my car. I went for a nice drive today up the mountain, and the weather was around 35 degrees celcius (95f), so it was pretty damn hot.

Towards the top of the mountain, i came to a full stop and noticed my oil pressure light was glowing a solid red and my oil pressure gauge showing a reading of 0 PSI flat. I also noticed my oil temp hit 100+ degrees celcius (212f). I then immediately parked the car and turned off the ignition to let the oil cool down. After 1/2 an hour of waiting i turned the car back on and i started getting around 7psi of oil pressure on idle (700rpm) with the oil temps around 82 degrees celcius.

Normally the oil light just flickers when the pressure drops to about 7psi, but because today it was at a solid 0 psi, i got a little worried. I assumed the light flickered cause the pressure sender was on its way out, but now i believe its stll working and is displaying a light for a reason.

That being said, if i revved the car to about 1200-1500 rpm, my oil pressure hits 30-40psi, and if i hit around 3-4k revs then im looking at about 80ish psi of pressure.


Anyone know what the problem could be? And should i be worried? Is my bearings fried? Do i need to rebuild the motor ==; Or is it something small?


Things to note:
- 10w-40 Fully synthetic penrite racing 10 oil was used in the car
- Cams are stock
- car has done 90,000Kms
- Its an evolution 7 GT-A

evolve_VIII

iTrader: (11)

Do you have a mechanical oil pressure gauge on it? I would start with that before you think about a rebuild.

meckert

iTrader: (11)

since we are not talking about unusual noises of any kind at idle or other-- I think you just need to change your oil pressure switch(sender). Now if for some reason, there is knocking and rattling at startup or idle that you neglected to make us aware of ---then you can rebuild then.

deza3000

I have 2 sources where i get my pressure readings from, one is from an electrical gauge hooked up to the oil filter block, and the other is just the factory oil pressure switch. Should i invest in a mechanical gauge? Or would that just give me the same results as the electric?

As for unusual noises, there really isnt anything at idle or start-up, not that ive noticed anyway. I dont think lifter noise would count?? Idles normal. Sometimes when the radiator fans turn on, the car drops revs and the oil pressure light starts to flicker and i see oil pressure of around 7-10 psi from the electric gauge.

Additional info:

Under spirited driving, it goes as low as 4psi at idle, sometimes lower, it usually drops pressure as the oil gets warmer.

E.g. @ 60c =20psi oil pressure @ idle (800rpm)
70c =15psi oil pressure @ idle (800rpm)
75c = 9-12psi oil pressure @ idle (750rpm)
80c = 4-6 psi oil pressure @ idle (rewvs drops to 600rpm)
90c = 2-4 psi oil pressure @ idle (revs drop to 600rpm)

Ill change the oil tomorrow and see what happens. I only use penrite racing 10 or Motul. 2 most expensive oil's i can find here at our stores.

Oh and thanks for the quick replies, appreciate the help

batty200

iTrader: (3)

Most electronic senders are very inaccurate at the high end low ends of the spectrum. Since our cars spec around 10-15psi Max at idle it is very possible you have nothing to worry about except the sending unit. However I would recommend using some thicker oil like 20w50 or at least 15w50. On a built motor a lot of times the clearances are built to allow for higher viscosity oil and if you run 10w30 or 10w40 especially in summer you will notice low pressure at idle and may not protect your engine properly. However I have killed many aftermarket pressure senders with 4G63 engines because we tend to get very high oil pressure at high rpm.

batty200

iTrader: (3)

If this is a stock engine I would bet the balance shaft belt could be broken. I had one where it was and it causes low oil pressure at idle because the shaft isn't spinning. I would check that out asap.

TomekEVO

iTrader: (1)

Where is your oil pressure sensor installed ? If its in the oil filter housing or on a sandwich plate between the oil filter and housing it self. The sensor that reads the pressure might be broken due to the excessive vibration it happens and could actually leak which will cause engine problems. Check if you have any oil leaks by the sensor if its mounted in the housing because it might be broken.

If this is the issue I would either buy the AMS sending unit extension(around $35) and mount in on your firewall where its safe away from vibration or just fab up your own which shouldn't be hard. Either way it is cheap insurance which will prevent the future sensors from being broken

deza3000

Yep everything is stock except exhaust, mr evo 9 bov and tune.

Ill probably invest in a new sender then, but i have no clue where it is :/ I saw a few other threads and it seems to be right under the intake manifold. Such a bad place =='

Ill take a look at the balance shaft as well, would that require me to change the timing belt???

As for the oil pressure sensor, there is a sandwhich plate between the filter and housing. I dont think there is anything wrong with it considering i just got them installed last month.


Update: Flushed out the old fluid and replaced oil filter, i also increased the idle speed via the thottle body screw to 950(i know its not recommended but i do not have any evoscan/cables etc so couldnt adjust the tables). I decided to go with "Mobil 1 Ultimate all round performance" 0w-40, it was the most expensive oil there and the same oil was being used in one of the owners ferrari so thought id give it a shot. I gotta say, the car does rev up much quicker with the new oil, and i didnt get any oil pressure lights. Oil pressure at idle was a stead 10-15psi. However im not sure how long that will last, i have a feeling if i go for a proper spirited drive, the pressure light will come back on. And im sure the ECU will bring the idle back down.

Car is running fine at the moment, i acutally was planning on doing a e85 tune, evo 9 turbo upgrade and fuel pump upgrade next week, but got diverted because of this I should be fine to go ahead with my original plans??

barneyb

Change the sender for the light. They have a long history of failure.

kaj

iTrader: (60)

How much oil was showing on the dip stick when all this was going on?
Also, the balance shaft doesn't need to spin in order to regulate oil pressure.