Oil pump/pressure whoes.

Alan

G-Wagen Club SA
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Oct 12, 2008
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Thought I must share my experience installing a rebuilt engine after transferring various components from another running engine that had head issues.
So after I transferred the oil pump, sump, power steering pump and injector pump I noticed I did not get oil pressure when starting engine.
I worked backwards from the sender unit to the filter housing and back to the pump. I could find nothing wrong, but stripped and cleaned the various parts while off.
On the pump I think there could have been an issue with the pressure relief valve but it was working in the other engine so not convinced.
Anyway, I assembled everything again and after some cranking (without glowplugs) and injector pump shut off lever activated, I still did not get any indicationthat the pump was pumping oil.
Next I cracked the filter housing off the block and cranked again. This time I got some oil at the outlet of the block. I tightened up the housing again and cranked again. Voila the housing was filling up with oil. I now kept cranking until the oil cooler was filled and I got oil pressure of 1 Bar+. Fitted the glowplugs and started engine.
Oil pressure shot up to the 3 Bar mark all good.
 

fig

G-Wagen Club SA
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Mar 7, 2013
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Lindequesdrif
We had a similar issue recently with a M102 200, which wouldn't build up oil pressure after rebuild. Only after we primed the pump with vaseline did the engine develop full oil pressure and has been running fine ever since.
 

Dikfrik

G-Wagen Club SA
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Oct 10, 2008
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Empangeni, Zululand
Alan any idea what would be the cause for this - as i understand the oil pump is a positive displacement gear pump which must pump when it turn if is has oil in it - was the pump not primed until you remove the housing? If so why did removing the filter housing resulted in the priming of the pump?
 

Alan

G-Wagen Club SA
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Freek, that is the strange part, after cleaning it out I put the pickup into the sump that I filled up with oil again and used a drilling machine at slow speed to test and it was there virtually instantly. So I am still not sure what caused this. Surely can't be an airlock?
 

Dikfrik

G-Wagen Club SA
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Empangeni, Zululand
In my experience with water networks especially small diameter systems airlocks can cause major problems - with the filter closed the system is a closed system but i am sure it re-circulates back to the sump and a positive displacement pump should push any air through? But perhaps the closed filter housing at a higher level could prevent the pump from priming??
 
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