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-   -   Leaking Front (oil pump) Cover (http://d24t.com/showthread.php?t=1206)

ngoma 02-27-2014 01:37 PM

Leaking Front (oil pump) Cover
5 Attachment(s)
Evidence will be an oil leak at the lower front of the engine, near the crankshaft, but without oil slung out along the rear edges of the cogged crank gear and damper pulley. Oil slung out from the pulleys indicate a leaky front crankshaft main seal.

Also, verify the oil is not leaking down from above-- valvecover leak is very common and can leak straight down the front.

The front cover/ oil pump cover can leak from the gasket, and there is a section there that sees high oil pressure.

Replacing the gasket should stop the leak.

Steps involved:

Remove timing belt, crankshaft damper pulley and cogged gear

Disconnect front engine mounts and lift engine

Disconnect steering column clamp

Lower front crossmember.
(This allows for dropping the oil pan sufficient to remove the front cover)

Drop oil panAttachment 331Attachment 332Attachment 333

Disconnect oil pickup tube from front cover. Note there is a tab lock plate.

Bend the tabs out of the way from the flats on the bolt heads.Attachment 334

Remove front (oil pump) coverAttachment 336

ngoma 02-27-2014 01:44 PM

1 Attachment(s)
Note the leak here-- the gasket is broken thru (near the very top of the photo).Attachment 337 This happens to be right where the oil pump hi-pressure outlet is, so it sees high pressure (80PSI?). BTW, the brand new replacement gasket (still in its intact sealed-bag original packaging) was folded/mutilated here at the exact same spot. We almost installed it! Had to end up waiting for a replacement.

Install new front crankshaft main seal

Install new oil pump front cover gasket

Reattach oil pump front cover

Reattach oil pickup tube, bending the locking tabs to lock the bolts

Clean oil pan and block mating surfaces, install new oil pan gasket, reattach oil pan.

Reattach front crossmember, steering coupler, engine mounts, etc.

Reinstall timing belt, retime engine and IP.

v8volvo 02-27-2014 03:05 PM

FWIW, the biggest hassle of this job is just removing and reinstalling all 20+ of the oil pan bolts -- other than that, more straightforward than you would think! I didn't take any pictures as it went back together, but it was not bad, even getting the x-member and motor mounts lined back up was not difficult. Cleaning pan and block gasket surfaces was a little tricky because of the close quarters, but if we had removed the pickup tube fully (another 3 bolts) the pan could have been removed fully rather than just lowered. I think that would be a better way to do it the next time.

I had never seen a leak in this location before, but getting the new gasket with a break in the same place made it pretty clear how it could happen. This car (a converted gas 960) had just had an alternator belt replacement weeks before this leak sprung, and in the final stages of buttoning it back up, I discovered that the alt bracket bolt (which goes thru pump housing into block) was too short and had pulled threads, wasn't clamping at all. The engine had put on about 1000 miles since rebuild without leaking, so I suspect the gasket was compromised as ngoma described at installation, and then losing the clamping at that point let it move a little more and tipped it over the edge. Big leak! If the rebuilder had noticed the damaged gasket, it probably wouldn't have leaked, but maybe eventually still would have had an issue b/c of that bolt. Fortunately still had enough threads further down that a longer bolt had something to bite.

One area where we were lucky to save some time: removing timing belt, I pulled the idler roller out of the front cover rather than disturbing water pump position (and belt tension), then reassembled the same way -- never popped cam sprocket off to set timing, only reinstalled belt, idler and crank sprocket. We checked timing at the IP before disassembly (*cold* engine so as to ensure no timing shift due to expansion of block and head), and again after, and it did not change. A little bit of luck here because the crank sprocket's key has a bit of play, but no complaints! Not having to take off cam sprockets and valve cover for full timing procedure is a good savings of work, if it goes in your favor.

Might want to add to the above list: battery + cable clamps have to be separated at RH motor mount and front of member for member to drop, and power steering connections at the rack have to be disconnected (and p/s fluid refilled afterwards). The 960 only needed one of the connections (return IIRC) taken off because the pressure hose was longer, but a stock 740 would need both. None of the steering and suspension parts have to be disconnected; if engine is also lifted a couple inches from above, the x-member can hang on the struts and drops far enough to get the pan down with ease, and the crossmember goes back in with guide pins so front end alignment doesn't change significantly.

verdigo 03-23-2014 09:51 AM

The oil pump housing has the alternator pivot bolt going through it. If changing belts or otherwise screwing with this alternator belt do not over torque as it will squeeze the gasket and make it leak eventually. Ask me how I know this.. Pain in the butt on a 245 to replace this gasket. Poor design for alternator mounting IMO.

RedArrow 02-23-2015 06:54 PM

Dangers at Oil pump housing

Originally Posted by verdigo (Post 8350)
The oil pump housing has the alternator pivot bolt going through it. If changing belts or otherwise screwing with this alternator belt do not over torque as it will squeeze the gasket and make it leak eventually. Ask me how I know this.. Pain in the butt on a 245 to replace this gasket. Poor design for alternator mounting IMO.

Such a stupid design!! I have to get the 740 alt belt done `v8volvo style` this week. It`s getting a Gates XL 7300 belt. 9.5-10mm wide, 780mm long. A bit wider than stock, and a bit longer than stock Volvo #966894 (9.5 x 750La) d24t belt which is discontinued. Cross reference charts at Napa shop made me buy the Gates belt (2x, in case it screws up on the road). I expect my regular belt-squeaking issues and sudden voltage drops go away. (belt slips at electric loads---i guess it`s also not tight enough)

Anyone knows the torque spec on that bolt?

jpliddy 02-04-2018 10:21 AM

940 tdi auto 1995
thanks guys for your valued info . the leak is seamed to have stopped i gave the whole area a good clean im thinking oil is coming from the rocker cover maybe this 10 40 millers oil oil sure does travel over time its a bit misty at the front of the rocker cover so over time it may come back i will keep you informed
regards jim

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