Whats the best oil to use to run in an engine

[cneculae]

Hey guys

I need to know which is the best oil to use in order to break in a rebuilt engine. I tried using 10w30 but it seems that my oil pump will not stay primed and it looses oil pressure after it sits for a few hours.

I was curious if the heavier thicker oil will work and keep the oil pressure up.

Any info would help.

Thanks
Cristian

 

[DieselTech]

What engine?

 

[demarpaint]

What engine? In most cases 10W30 is fine. Are you sure something isn't wrong? Did you prime the pump before firing up the engine for the first time? How do you know the pump has lost prime?

Oh yea, welcome to BITOG!

 

[Bill in Utah]

Read this THEN ask your question

 

[expat]

Hey guys

I need to know which is the best oil to use in order to break in a rebuilt engine. I tried using 10w30 but it seems that my oil pump will not stay primed and it looses oil pressure after it sits for a few hours.

I was curious if the heavier thicker oil will work and keep the oil pressure up.

Any info would help.


No engine will maintain oil pressure if it is not running!
Please restate the question.

 

[Zaedock]

My engine loses pressure right after I shut off.

to the forum!


I'm not sure what you're trying to ask here. When you restart your engine, does it not have oil pressure?

 

[mechtech2]

I'd be concerned that a 10-30 is too thick for flow when starting.
I'd want a 5-30 in there .
If after one start [your first start]your pump is losing prime, you have mechanical problems.
An oil filter that does not have the proper leakdown valves is another possibility.

 

[cneculae]

Ok sorry about the lack of info.

I have a 1992 Toyota Starlet (4E-FTE) Engine in a 1991 toyota tercel. I will describe the issue in more detail so you can understand what im talking about.

Initally after I completed a top end rebuild( head gasket, valve cover gasket, port and polish head, front and rear main seal etc) I went to start the car. It started up right away with no problems at all. After it ran for about 2 minutes it shut off by its self. What happened was my oil pump ceased up and cased the timing belt to skip a few teeth.

I replaced the pump as well as the oil pressure regulator valve and primed the pump using a drill to spin it at high RPM. After that i noticed there was oil coming out of the oil filter housing. So there for I put everything back set the timing and started up the car.

I drove it for about 5 miles or so then I brought it back home and shut it off so I can change the oil on it. So i started it up again and moved it into the garage I noticed on my gauge (which works correctly) that there was no oil pressure. THe car had only been sitting for about 1 hour.

So my question is should I use thicker oil so that when I turn the car off and I start it after a few hours I will have oil pressure?

Everyone I have talked to about this including mechanics, auto parts people, etc said they have never heard of anything like this before. So it is a unique situation.

Any help would be appreciated.

 

[Zaedock]

Viscosity is not the issue. Sounds like a mechanical problem to me. You could start the car with 0W20 on a 100*F day and there should be oil pressure.

 

[demarpaint]

Originally Posted By: Zaedock
Viscosity is not the issue. Sounds like a mechanical problem to me. You could start the car with 0W20 on a 100*F day and there should be oil pressure.


+1 it is not the oil, could be a bad pump especially if there is no pressure at all.

 

[jazeo]

As soon as the engine fires the oil pressure gauge should come up, I'm talking less than a second. the only time it would take a bit longer is after a oil change and even then it's probably only a second. If this is not happening, your problem is not the oil or it's weight. It's mech...

 

[jazeo]

"So my question is should I use thicker oil so that when I turn the car off and I start it after a few hours I will have oil pressure?"

Also:
I can't help but feel you seem to think the engine should have oil pressure even with it not running, that's not the case. 0 pressure when not running, so using a thicker oil is not gonna make a difference.

 

[440Magnum]

You said you parked it so you could change the oil and that after you restarted it the pressure was zero. Did you partially fill the oil filter? Even if you do that, it will take a couple of seconds for the pressure to come up after an oil change. If it doesn't come up after a few seconds, then you may have a mechanical problem.

Either way, this is NOT going to be cured with thicker oil.

 

[cneculae]

Ok thanks for the insight guys ill start again eliminating one thing at a time.

 

[mechtech2]

Your oil pickup may be clogged - Sludge, debris, pieces of gasket or RTV, etc..
It stinks, but you gotta yank the pan and clean everything out.
How else are you going to be sure?
Pull the pick up off and also check the passages as best you can.