Get a better experience by installing our free app!
Not now
Install
Get a better experience by installing our web app!
Hide
How to do it?
In Safari, tap on the menu bar. Scroll down the list of options, then tap Add to Home Screen.(If you don’t see Add to Home Screen, you can add it. Scroll down to the bottom of the list, tap Edit Actions, then tap Add to Home Screen.)
Well that's weird. Sorry about that. Were the oil filters the same brand? And was the replacement new (empty). New/empty filters take a few seconds to fill and and show pressure on the gauge. What oil are you running? If the pump is losing its prime as it sits overnight, maybe its worn out? How old is it? I can't really see how a cracked pick-up could do that, unless it's like poking a hole in the bottle of a bottle to get it to flow? A sticky OPRV could though, but it seemed/seems like it's more about not getting the pump primed in the first place. If it keeps doing that, you may have to do exploratory surgery after all. Let see what MM says. He's the brains of this outfit.
This is after about an hour since last start. Acted the same way as it did after the last break. My reading says the couple of seconds of clatter while the pressure builds is ok?
At lunch today went to see where we stood. Last time cranked was about 8:30 last night until 12:45 today.
No oil pressure and the valve train clatter has returned.
So...it appears that all of the oil is draining back out of the top of the engine after it is shut down. I do not know how long it is actually taking. After an hour or so everything was still good.
I really need a good diagram of oil flow. I THINK I understand it to be that the oil is picked up from the sump and travels to the front of the block along the girdle. The pump then forces oil into the block at the OPRV which then goes to the filter housing, then out to the oil cooler and back to the block.
So - I understand that there is a check valve in the head that is supposed to keep oil from flowing back down to the block. I t would appear at firth thought this could be the problem. Full transparency...I had no idea there was such a thing and as such had no idea to check it when I had the head redone.
I also understand that the OPRV *might* have some function in keeping oil from flowing back down to the sump somehow, but....the laws of gravity would suggest if the head check valve were working it would not matter what the OPRV does as the oil would at least stay in the head - which based on the sound it is not.
So I am just trying to determine next steps. Do I start with the OPRV? I also thought that a stuck OPRV would cause no or low oil pressure - once primed, mine is fine - another sign that might be ok and the head check valve is not correct.
Please weigh in as you all have been doing. At least just the cam tower has to come back off for the check valve.
Again - my first issue is not having a firm grasp of the movement of oil through the system and where it should drain back from and stay when the engine is off. Knowing that may help diagnose.
One other note - the car is on front jack stands as it has been for quite a while now while I sort this out in my spare time. Would the front end being lifted in any way contribute to the drain back and once the car is on level ground all would be fine? I would not think it would matter but as with most things related to this car I just never know.
The lifters should not clatter like that if they were quiet a few hours before. Starting the engine from cold with the pressure valve in the head off should give a pressure of 3 bar only, so if the pressure goes to 5 then it seems the valves does restrict oil flow to the cam housing but perhaps stays open when turning off the engine.
What year is your car? If it's an '86 then rather than a sealed valve there may be a ball + spring set up, in which case there is no visible bolt visible on the side of the oil valley going up, on the head, from the block to the cam housing. Post a pic so we can see what you have. Not sure how the ball could stay up when turning off the engine but then I'm not familiar with the ball + spring set up on 8V heads.
Were the oil filters the same brand? And was the replacement new (empty). New/empty filters take a few seconds to fill and and show pressure on the gauge. What oil are you running? If the pump is losing its prime as it sits overnight, maybe its worn out? How old is it? I can't really see how a cracked pick-up could do that, unless it's like poking a hole in the bottle of a bottle to get it to flow? A sticky OPRV could though, but it seemed/seems like it's more about not getting the pump primed in the first place. If it keeps doing that, you may have to do exploratory surgery after all. 
