Oil Pressure Light on E30 S52

[cbouchez]

Safe to say that 15W40 will be fine for the 24V?

[nrubenstein]

Safe to say that 15W40 will be fine for the 24V?

Why would you run 15w40?

[cbouchez]

All the research that I've done it looks like it's a good weight. I'm open for options, I'm new to the S50 world and loud ticking valves are driving me crazy. I need to know if the oil weight will make a difference or I just have to live with the loud ticking for now.

[nrubenstein]

All the research that I've done it looks like it's a good weight. I'm open for options, I'm new to the S50 world and loud ticking valves are driving me crazy. I need to know if the oil weight will make a difference or I just have to live with the loud ticking for now.

15w40 is usually a non-synthetic crappy oil. Not universally, but typically.

Assuming that your oil system is working properly, clacking lifters under normal driving conditions mean that they are sludged up and clogged. Heavier oil won't fix this, and might actually make it worse (or at least is less likely to clear the sludge out). What you may need to do is pull the lifters and try to clean them out or just replace them.

[cbouchez]

Thank you for the info.^

[MaxBell]

Question: could a bad head gasket cause low oil pressure?

[M3PO]

Question: could a bad head gasket cause low oil pressure?

Highly doubt it. There are oil supply (and drain) passages that go from the block into the head which of course pass through and are sealed by the head gasket. Those passages would have to be leaking a MASSIVE amount of oil either externally (onto your driveway), into the coolant, or into the cylinder(s). All of these would be obvious and are extremely unlikely.

[sweet3]

I believe 0w40 is the standard weight that is used by the factory. I'll let someone chime in on that one.

When you say that your oil light is on, is it on even if you rev it up a little bit passed idle? Even mine flickers when the engine is warm at idle. I believe thats just because the original m20 and the s52 operate at different pressure when at idle.

[ForcedFirebird]

I believe 0w40 is the standard weight that is used by the factory. I'll let someone chime in on that one.

When you say that your oil light is on, is it on even if you rev it up a little bit passed idle? Even mine flickers when the engine is warm at idle. I believe thats just because the original m20 and the s52 operate at different pressure when at idle.

15w40 mineral is what BMW recommended. We run Liqui Moly 10w60 in them (comparable to the later OE Catrol).

The 24v engines seem to have a lower oil pressure at idle than the m20, but the dash light shouldn't come on with either engine.

[SnowB0und]

Did you prime your oil pump. Mine didn't get pressure when cranking with the plugs removed right away. I poured a ton of oil in through the oil filter housing to be safe, pressure came right up after that.

[e30rapidic]

An old mechanics trick is to run quart of ATF in with your oil before you change it. let it idle for 15 minutes or so before you drain it. That has worked for me.

If you have more time and have the aptitude to pull your cams out and put back together, you can use this as a guide. I rebuilt the lifters in my S50 and they are identical to these.

And yes, it's from a Geo Metro forum but it has good pics for reference.

http://geometroforum.com/topic/3937058/1/

[MaxBell]

15w40 mineral is what BMW recommended. We run Liqui Moly 10w60 in them (comparable to the later OE Catrol).

The 24v engines seem to have a lower oil pressure at idle than the m20, but the dash light shouldn't come on with either engine.

I wonder how low?

FINDINGS

FIRST
The head wasn't torqued down properly and there was coolant in the oil. Changed the oil out, didn't fix the oil pressure problem tho.

THEN
I got an oil pressure gauge on it and it went like this:

IDLE COLD: 20 psi
IDLE WARM: 5 psi
3500 RPM: ~40 psi
REDLINE: 65 psi

The light comes on at idle after a few minutes of idle/warming up. The lifter tick is pretty loud, though that could be coolant in the lifters? How would one flush those?

We're using an M50 oil pump here, would that matter? The S52 and M50 oil pump seem to have the same part number?

Anyways, any help would be appreciated.

[sweet3]

I wonder how low?

FINDINGS

FIRST
The head wasn't torqued down properly and there was coolant in the oil. Changed the oil out, didn't fix the oil pressure problem tho.

THEN
I got an oil pressure gauge on it and it went like this:

IDLE COLD: 20 psi
IDLE WARM: 5 psi
3500 RPM: ~40 psi
REDLINE: 65 psi

The light comes on at idle after a few minutes of idle/warming up. The lifter tick is pretty loud, though that could be coolant in the lifters? How would one flush those?

We're using an M50 oil pump here, would that matter? The S52 and M50 oil pump seem to have the same part number?

Anyways, any help would be appreciated.

ForcedFireBird is on the right track. If both engines are still in their original chassis, then the lights should never come on while the engine is running. However, the m20 gauge cluster is programmed for ~7psi. That's why your light tends to come on after a while of warm idling. If you compare your current readings to an E36 with the same engine, you will notice that the pressures are about the same, but the light isn't coming on.

To fix your ticking, you will probably end up needing to remove your lifters and clean them. You need to remove the little piston inside the lifter and clean the old oil out. Otherwise, you are looking at replacing your lifters. It not easy to find out which ones are ticking (maybe all of them). If you clean/replace any of them, it's best done as a set.

The pumps won't make much of a difference (unless the one is worn out inside)

[MaxBell]

ForcedFireBird is on the right track. If both engines are still in their original chassis, then the lights should never come on while the engine is running. However, the m20 gauge cluster is programmed for ~7psi. That's why your light tends to come on after a while of warm idling. If you compare your current readings to an E36 with the same engine, you will notice that the pressures are about the same, but the light isn't coming on.

So is 5 psi ok for an S52? So I understand, are we staying that I should just ignore the light?

[ForcedFirebird]

The ticking lifters may clear up after some hard running of the engine if it sat for extended periods of time.

You need 1psi per 100rpm. If you have thin oil and a manual, it's a good chance a 24v will trip the e30 light at 6-700rpm.

5psi is on the low side, but not by much - specially if you have 65psi at oil relief.