No oil pressure at startup

[Mr. Y]

Hello.
I have problem: sometimes I have no oil pressure when starting engine for 1-2 seconds. It happens when car is not driven for 6+ hours, but not every start. The engine sounds loud at this moment, but quites when pressure raising.

I'm going to drop oil pan, remove oil pump and inspect it (also shim relief valve). May be change rod bearings also, once I'm there.

Can you give me ideas, what else (besides oil pump) may cause problem?
And as for removing pan... I can't pull engine, so I'll going to jack car high enough, drop front subframe and so on (as TSRM describes oil pump removal)... May be are there some tricks, that are not described in TSRM? Anyone have done this job (rod bearings and pump with engine still in car)?

PS: oil system is stock (but will be upgraded soon for t-stated cooler and filter relocation kit).

 

[MDCmotorsports]

Sounds to me like you have a horrible drain back problem and the oil ports are draining over night.

I'll let the others chime in here since the oil pump isn't my area.....

 

[JustAnotherVictim]

Check the wire going to your oil pressure sender and the sender itself while you're looking for things.

 

[jdub]

What weight/type (syn?) oil are you using?

 

[Mr. Y]

MDCmotorsports
I think the same. But how can I fix it?

JustAnotherVictim
I _hear_ engine knocks at startup and then sound goes out. So it definately not sensor problem.

jdub
10w40 Castrol Magnatec. Outside temp is +7*..+20* (Celsius) here.

PS: My theory is that oil pump is out of spec (too big gaps) and oil drains back to pan. Or may be I'll try another oil, but at first, I want to be sure, that pump is ok.
PS2: And what about doing job? Any advices here?

 

[jdub]

IMO you have several potential things going on:

- You do have a drain back problem...the oil pump pressure line is a candidate. The oil pressure relief valve on the pump is a possible cause. The oil filter may not have (or is not working) an anti-drain back valve.

- Use a 5W-30 or 0W-30 oil to improve flow, especially cold.

- You also may have worn bearings...what is oil press with the engine at operating temp at 3000 rpm?

Concerning the job you are considering...it is a royal pain to do with the motor in the car. Get a new oil pump...make sure it's a pump for the turbo. If you shim it, 2-3 (2-3mm thickness total) washers is plenty. When you put the pan back on, use Toyota FIPG in the tube or, if available, Permatex "the Right Stuff"...it's easier to apply. If you replace the bearings, pay attention to the Toyota numbering system for the bearings...torque spec is critical...double check clearances. Make sure the rod caps do not get mixed up.

 

[Mr. Y]

jdub
Thank you for help, I appreciate it.
Problem is not in filter (I use OEM toyota filters, tried another with no success).
As for bearings and pump, my engine was rebuilt (about 15K miles ago) and pump was replaced (I haven't seen new one, but they gave me an old with 100+K miles on it). Bearings were replaced too. But that rebuild was nasty and engine builders are stupid.. Anyway, I don't trust them (another long story). That's another reason to repair oil system and be sure, that _this part_ is ok.
Oil pressure looks good (about 3 bar at 3K rpm).
Unfortunately, it's hard to get "right stuff" here, but I'll use best replacement I can find.

 

[jdub]

That pressure is good...leads me to believe your bearings are ok.

BTW - Toyota filters are not that good. If you can get PureOne or Wix, either would be a better choice. The Toyota filter should not be causing a drain back problem though.

 

[Nick M]

It could be his oil itself.