Gear Oil Leak

[peixcman]

I have a 2001 XC70 with 70k mikes on it. I noticed a small puddle of gear oil under the bellypan this morning. Right side of the belly pan seems to have more coated on it than the rest. Definitely gear oil. Any suggestions?

[volvoshad]

I have a 2001 XC70 with 70k mikes on it. I noticed a small puddle of gear oil under the bellypan this morning. Right side of the belly pan seems to have more coated on it than the rest. Definitely gear oil. Any suggestions?

Don't drive the car until you have checked the bevel gear oil level. Instructions and picture here. The bevel gears have a tendency to leak at the seals, but I have not seen posts reporting puddles of oil, usually just sweating of the housing. You can also check the rear differential level through the fill plug. There are oil seals at each front drive axle as well, would check them - especially on the right it would seem - but I don't know if they would ever cause this dramatic a leak. Let us know what you find.

[peixcman]

Wouldn't the axle seals leak auto trans fluid instead of gear oil?

[BillAileo]

I believe you are correct. Be aware that the bevel gear only holds about 750 ml of gear oil, so if it is the source of the oil you described, I concur in the advice not to use the car until the problem has been resolved.

Bill

[KCsXC]

I have a 2002 V70XC and noticed similar oil spot on my garage floor a few months after buying it around the 22k mark. Leak was traced to what volvo calls "Bleed Valve" in the bevel gear assembly. It was replaced under warranty accorrding to Service Bulletin 4-46-0008. Parts they used PN 8689251 Air Vent Valve, PN 1161648 Transmission oil and PN 11998 Gasket. At the same time they inspected for other leaks and found a leak on an oil cooler hose PN 31104689. This was also changed when the car was still under warranty.

KC

[MoeB]

Is this enough leakage to be a problem? If so what's the fix?

[volvoshad]

MoeB, did you pull the fill plug and check the level?

The fix is to remove the bevel gear and replace the seal and bleed valve, I believe. I think it is another aspect of Volvo "routine maintenance."

[MoeB]

Damn...shoulda done that yesterday when it was up in the 50s. My kingdom for a heated garage! Oh well, guess I better get out there before the driveway concrete gets any colder.

BTW, where's the bleed valve? I know there's a vent on top (#16-17 here), but not sure where the bleed valve is. Also, I thought I read somewhere that the vent gets clogged and pressure builds up, causing seal to fail. If true, would that normally be a warranty thing? Anyone have info on this?

Update:
OK, checked bevel oil level. It was about .1 to .2 L low best I could tell. So the leak is slow right now. I sucked a little of the old oil out to see what it looked like, then topped it off with new. It was a little dirty but not as bad as I expected given it's at 52k now. Looked about like pancake syrup. Old is on the left, obviously:

[Ragman]

That does not look bad compared to what I pulled out of mine this past Saturday. Mine looked like really old, black, motor oil and the box was about 150ml low after 101,000 miles.

I had seepage that left wet spots on shield and gear box oil pan. I wonder what's wearing out to cause it to be so black?

[MoeB]

I wonder what's wearing out to cause it to be so black?

Metal. I think also the oil oxidizes over time from the high heat, which probably darkens it as well. If you wanted to know for sure you could send a sample to a lab for analysis. I'm just going to replace mine and be done with it. If my warranty covers it, I'll let the dealer do it when they fix the leak. If not I'll change oil myself and wait for the leak to get worse before fixing it.