loss of oil pressure - PeachParts Mercedes-Benz Forum

mbhack · #1 02-24-2004, 05:40 PM

has anyone experianced loss of oil pressureonce the engine starts to warm up , after 5 min of idling on a 123-130 chassis
617-912 engine non turbo. 1980.
i rebuilt the block and head
i removed the oil filter housing and placed it the hot tank.
for cleaning along with many other parts
has anyone heard of the thermostat in the oil filter housing
go bad after cleaning?

RockinWagin · #2 02-24-2004, 06:03 PM

What oil pressure readings are you getting at what temp?

SW · #3 02-24-2004, 06:06 PM

Give us more info. How much oil did you fill the engine with before cranking it up? Also, define loss of oil pressure. Did the engine seize while idling or did the oil pressure reading at the gage drop while idling?

leathermang · #4 02-24-2004, 07:31 PM

You need to check and see if the screw in oil pressure relief valve is still in your oil pump.... if yes, clean it well and use locktight when replacing...

mbhack · #5 02-24-2004, 09:11 PM

WHEN FIRST STARTED COLD THE PRESSURE WAS AROUND 2 BAR,
AS IT WARMS IT DROPS TO ABOUT .8 BAR.
I FOUND SOME OLD MICRO FILM , GROUP 18 . FOUND THAT THE OIL FILTER HOUSING HAS A THERMOSTAT INSIDE AND WAS WONDERING IF THE HOT TANK DISTROYED IT.
I ORDERED ALL THE GUTS OF THE OIL FILTER HOUSING AND WAS BACK ORDER GERMANY (DIDNT SUPRISE ME)

mercedesmatt · #6 02-24-2004, 11:46 PM

did the oil pressure drop show up right after you rebuilt the engine???? if so id say take a look at your bearings, id bet you have too much oil clearance on the rod bearings.

mbhack · #7 02-25-2004, 01:45 AM

no the engine did'nt seize, i dint run it more than 5 min.
i added about 7 quarts of oil.
this is a fresh motor
i had the block sent out and bored/ honed 2nd over.
crank was untouched. replaced all crank bearings and
connecting rod bearings. plastigauge an all.
i just removed the sub oil pan for inspection. i checked the
pressure release valve and cleaned it- it looked fine.
before taking engine out the oil pressure was normal,
this car has 119k miles and had major blowby, i found cracked rings. im going to try the oil filter housing before pulling the engine again

thanx

william rogers · #8 02-25-2004, 02:11 AM

Maybe you need a new oil pump,did you fill the pump with oil before instaling it.when I had the oil pump out on my 500SE it would not self prime had to take it back out and put it back in full of oil...........

William Rogers..........

leathermang · #9 02-25-2004, 05:08 AM

Did you take the steel balls out of the back of the block and hot tank the block ?

leathermang · #10 02-25-2004, 06:26 AM

" Complaints concerning engines 616.916,617.910 "
On these engines, when engines are cold, oil noises or a pressure drop may occur ( at idle below 2 bar with cold oil or 1 bar with warm oil. As a remedy , the oil pressure relief valve of version C may be installed"
Loose or dropped oil pressure relief valve can be screwed in using sealing compound part nu 0029899471."

I think the only way you can check the oil pressure relief valve is by putting pressure on it... visual check might not be sufficient...and ... can it be put together backwards ?

Stevo · #11 02-25-2004, 11:00 AM

mbhack

When I rebuilt my 616 last year I had the problem of NO oil pressure when I lit it off. Turned out I left the 2 plugs out of the ends of the oil gallerys. One thing I did was pump oil through the engine with one of those plastic hand pumps used to pump tranny or differentel oil. I put a fitting where the oil pressure gauge attaches to the oil filter housing. I warmed up a couple of qts in the house. After the filter is full the pumping should be fairly hard if not the oil is "running through" too easy. There are allot of things to do before pulling the engine. I installed an oil pump once and had the drive gear turned upside down, again NO oil pressure. I would swap out the pump first and prime it by turning it by hand in a can of oil till oil comes out the top, then reinstall. Are you sure you put BOTH oil gallery back in?

psfred · #12 02-25-2004, 01:23 PM

The pressure relief valve is in the oil filter housing, and you probably fried it by hot tanking.

A new one will fix it.

Peter

whunter · #13 02-25-2004, 01:27 PM

Hello Everyone.
Never hot tank a thermostat.
Now; back to our regularly scheduled program.

leathermang · #14 02-25-2004, 01:29 PM

Peter, are you thinking about the thermostat in the oil filter? My 616 manual shows the oil pressure valve as being screwed into the oil pump...

psfred · #15 02-25-2004, 10:14 PM

Quote:

If following oil filter change and oil pressure (0.5 atm) is indicated at idle speed, observe the following:

Ecessive force win inserting central bolt (1) during filter change may push the sealing ring (24) out of its hold position in from of header pipe(22). Oil will then be supplied via the overflow valve (8) wihch will result in a drop in oil pressure. To avoid pushing out sealing ring(24), insert central bolt into oil filter without using force."

Remove the filter and take a look in the housing. There should be a stand pipe in the bottom (the header pipe). If not, there's your problem -- the filter fits OVER it, there are three rubber seals in the center hole.

Otherwise, you managed to push the middle seal out of place and most of the oil is bypassing back into the oil pan. Either get the seal back in place or put a new oil filter in -- this time, oil the center "bolt" and don't push down too hard when putting the cover back on.

Peter