AAZ Vanagon -- Oil Pump Lost Its Prime?

[ryanoceros]

I am in the process of installing a new K14 turbo in my AAZ Vanagon. I drained the oil before removing the previous turbo, and so the van sat for ~1 week without any oil in the pan (my regrets now). I got the new K14 turbo bolted up yesterday, filled the engine with 4.5L of oil, and disconnected the fuel cutoff on the IP so that I could crank the engine and prime the turbo with oil. But, after several rounds of cranking, the drain on the turbo showed no signs of oil. This made me suspicious that the oil pump had lost its prime after draining for so long. So, I unscrewed the oil filter and cranked it several times for 5 seconds (spaced apart), and there was no oil coming from the filter flange. I do have a Mocal thermostatic sandwich plate installed adjacent to the oil filter, but I do not think that it should impede flow from the pump to the filter during startup.

So, I am thinking that my oil pump has lost its prime, and I am wondering if there is any simple ways to re-prime it? I have heard that it may help prime the pump by filling the engine with oil though the pressure sender ports on the top of the filter flange?

Thanks for the help!

[ryanoceros]

Just a bit more info:

The engine ran great before I pulled the turbo. Oil pressure was about 20psi at idle (temp ~180F) and increased about 10 psi per 1000 rpm.

I did not change the oil grade after installing the new turbo (kept it at 5W-40)


Is there a chance that the oil pump has failed? I am just baffled as to why there is no oil gushing out when cranking the engine with the oil filter removed.

[libbydiesel]

You can pull the vac pump and then use a drill and socket (careful not to drop it in the case) on the end of the oil pump to spin it and prime the system. 

[vanbcguy]

... the pump really shouldn't lose prime like you're describing though. I leave my vehicle sitting for a week all the time, there is absolutely no reason why it suddenly wouldn't have oil pressure after that.

[ryanoceros]

You can pull the vac pump and then use a drill and socket (careful not to drop it in the case) on the end of the oil pump to spin it and prime the system. 

Thanks, I will give this a try. Is there any reason that the drill method would work better than cranking the engine with the IP shutoff? The two methods seem to be doing the same thing, unless the intermediate shaft is not spinning while I am cranking?

... the pump really shouldn't lose prime like you're describing though. I leave my vehicle sitting for a week all the time, there is absolutely no reason why it suddenly wouldn't have oil pressure after that.

 I am also very baffled as to why there is no flow through the pump with the filter removed (to prevent any airlock that could have developed). Could the oil pump just have quit out, or be too worn to self prime?

[libbydiesel]

A drill will spin the oil pump much faster than the starter.  It's also a lot easier on the starter and the engine bearings than extended cranking.  Also, if it won't prime with a drill it sure won't no matter how much cranking you do with the starter.   

[theman53]

It looks like, I am guessing here, you have a different turbo and an oil cooler that were not there previously right? I would see if either of those parts are causing the issue by taking them out of the equation. Pull your feed line from the turbo and see if you get oil there, you could have it empty into the valve cover. Also, see if unhooking your oil cooler lines and doing similar you see anything...all this while spinning the oil pump of course. If you changed anything else that involves the oil system let us know. If it worked before it should work now.

[ryanoceros]

I actually installed the same exact turbo as I previously had, but I had it rebuilt by GPop because it was quite tired. Currently the drain line is not connected to the turbo, as this whole oil pump dilemma started when I was trying to prime the turbo for startup. The turbo feed line is new, and is also dry. I will disconnect the feed line and see if that helps. But, since the feed line to the turbo would receive oil post filter, I don't really expect it to be causing this phenomenon, since I can't even get oil to come out of the filter flange (strait from the pump).

I removed the oil cooler sandwich plate from the filter housing, and this did not help to get any oil flow from the pump. Additionally, that oil cooler was installed about a month ago when the engine ran. The only change I made when draining the oil this time was install the rebuilt turbo.

I will try using the drill today, and hopefully that higher speed will do the trick.

[theman53]

that is probably all it is. The feed line was to see if the turbo was not letting it drain.

[Dakotakid]

Did you happen to use some cloth to plug removed lines (to keep out dirt and roaches) while things were disassembled....then forget to remove them on assembly? Don't laugh....it happens.

[ryanoceros]

Libby was right about the drill method -- it got the oil pump primed in about 30 seconds.

I ran the oil pump shaft with the drill while watching for oil to appear at the filter flange, and then there was an audible 'burp' and lots of oil flowed out. I screwed on the filter, and ran the drill some more until about 1/4 cup of oil flowed from the turbo oil drain (my original goal, after all). I then reinstalled the vacuum pump, and cranked the engine for 5 seconds (with IP shutoff) to make sure there was still oil flowing through the turbo. I then reconnected the turbo drain line, started up the engine, and let it idle for about 5 mins. Oil pressure was 60 psi during the cold idle.

I am still baffled why the pump lost its prime like that. Is this whole debacle a sign that the oil pump is worn, or an odd case of airlock that needed the high rpms of the drill to clear it?

[theman53]

You had it open with no oil for a week. I believe that anything is going to lose the oil in that time. Why it didn't prime I don't know, slow starter, weak battery, who knows

[vanbcguy]

I've had a pump do exactly this before. It had some scoring internally. Once it was primed it was fine, but any air in there and it wouldn't have enough suction to pull oil from the pan.