motor:

- s5 6port turbo conversion
- s5 n/a block, stock s5 t2 everything else
- oil feed line taken from aftermarket oil pedestal
- tapped n/a cover for stock turbo oil return
- autometer sport comp elec. gauge in oil pedestal

problem:

Oil pressure upon initial startup of the motor was around 28-30 psi at idle and above 50psi at rpm. It has been on steady decline since (2-3 months).

Here are the symptoms as of tonight.

startup cold:

25 psi at 800rpm, 50 psi when I rev.

warm driving:

30-35 psi at 2k, 40-50psi from 3k on.

hot idling:

0-10 psi at 800, 15-20 psi at 1200.

Other:

- oil psi does not decrease (just stops around 50psi) at higher RPM
- 20w50 Castrol conventional
- Pure-one oil filter
- gauge wiring has clean, tight connection

What do you guys think? oil pump?

 

thermo wax in e-shaft? Has it ever been pulled and shimmed?

 

not sure what real numbers are but i doubt ur psi at idle is 80 ur stock gauge is prolly busted

 

dude, autometer oil pressure gauges are horrible. I had my sending units go out on two separate cars. this may seem rediculous, but buy another gauge first.

 

oh yea my guage is crap...... an aftermarket piece is def on my wish list.....

 

Why do people always assume its a bad engine when the oil pressure is down? I'm not trying to be an ***, its just thats what i allways hear first thing. How is low oil pressure directly caused by a bad engine?

I just went through this with my car. I was told to......test it with a good mech. meter. Use the stock OEM filter.

After that I started to look at the oil pump section. and I know there is alot that can be done there.

good luck

 

I will try to locate another gauge sender or mechanical gauge, but i don't think the engine is "bad"... runs strong and starts up right away, pulls strong, steady idle.

I'm looking to hear from the gurus what could be going on with the oiling system that could cause this ( from the oil pump, to regulators, to worn bearings, etc.), and if its repairable.

 

also, I have a actron mechanical fuel pressure tester from advance auto... could I use that as an oil gauge as well without damaging the internals?

 

hey man same thing happened to me. first thing first check the comp. then your sending unit ,and if still nothing it has to be oil pressure regulators and if still nothing try taking the front cover off, check if the black o ring is in place if not in place your losing pressure but good luck man . i did all this in order and of course it had to be the last thing i checked

 

comp? compression? I don't think it has bad compression as it starts up and drives fine.

anybody know if I can use a fuel presure tester for an oil pressure tester? will the pressure show different because of the different fluids?

what are the odds of the pump or regulators being the cause? what about the bearings? could replacing the pump and/or regulators help?

 

Oil pumps never fail.

Your symptoms point to a front cover o-ring blowout, but confirm with a reliable pressure gauge before you start tearing things apart.

Generally a fuel pressure gauge will be fine as long as it's rated for the pressure.

 

cool, i'll try it as soon as I get a chance.

 

On an s5 engine, the o-ring is not likely to fail unless it was improperly installed, in which case the problem would have shown up from day 1.

When worrying about an oil pressure issue, ALWAYS ALWAYS ALWAYS use an external mechanical gauge to verify current readings. 99% of the time the problem is not the engine or the actual pressure, it's the indicated pressure by a faulty electrical gauge/sender/wiring.

Run a mechanical gauge and check your results before taking any action.

For instance, I run FD OPR's in my FC engine which should make 35-110psi of pressure depending on RPM. Still my FC's stock gauge shows 30 at idle and 55-60 at higher rpms.

 

UPDATE:

mech gauge tested... pressure on the electric gauge accurate,

20-25 psi at startup
10 psi at 800RPM once it gets to operating temp

oil is a grayish color, similar looking to antisieze (for threads) but darker and without being shiny... Is that a telltale sign of anything??

 

Oil should not be grey. Are you losing coolant?

 

not losing coolant. The oil turns grayish as soon as it gets hot the first time. Also I forgot to say that it gets very thin as well (dripping quickly off the dipstick) even when cold, but doesn't necessarily smell VERY gassy, but slightly noticable

I am premixing to prevent a problem with a semiworking omp (2 lines won't fill up all the way). Is there a possibility im getting too much oil?? I premix 1oz a gallon, and I can't tell you how much if any is getting in by the omp. As of now this is my only DD so I can't tear it down as of yet, but should be able too shortly.

 

Premix won't do it.
Is your purge system workin properly?

 

what purge system? I have removed the charcoal canister and have no emissions on it. The tubes on the oil neck are open.

 

i just did some reading on grey oil... everyone seems to think its coolant related... I ran this motor for about 6 months before turboing it, and had no problems... then after the swap it seemed to be a gradual declining in the oil pressure.

Could the turbo itself be the problem? I am not an expert on turbos so I don't know if an internal seal failure can cause mixing or something like that.

I have not seen any oil in the coolant and not any noticable coolant typical signs (white goo, foaming, etc), but is it still possible?

In the beginning, after an oil change it would take 2 weeks or so to get low, but now it seems that as the motor warms up it goes down in sync.

 

It sounds like front cover o-ring is goners.
It's just about the only thing that'll cause those numbers.
Even the thermo pellet failure won't cause that drastic of an oil pressure drop.
Have you been driving it like this?
Sheez, it's been a while since the initial find, so there could be internal engine damage due to the low oil pressure.


-Ted

 

again its now my only vehicle and I have no choice... I have turned the idle up above 1000, but trust me I know its bad to be driving it.

 

i've also been changing the oil every 2 weeks or so to hold it off.

 

Has the front pulleys and / or the front oil cover been removed?


-Ted

 

not since i've had it no. we drilled the front cover on the car. We cleaned the pan the best we could, and I sprayed it all out and drained everything I could before running it.

 

Maybe we're looking at it the wrong way...

What ECU are you running? N370?
What fuel injectors (size) are you running?
Are you running an upgrade fuel pump?

Can you tell if the engine is running really rich?
Does the engine flood?

Can you tell if you're getting fuel into the oil?
Does the oil smell of gasoline when you change it?


-Ted