Thread: Why do 2.7 cranks break?

Pretty sure the flow is inside to outside - but happy to be corrected on this.

For a canister type filter it is outside to inside, but the cartridge type in the TDV6 I believe is the other way around.

This is why you cut open the filter to inspect what contaminates have been caught inside the oil filter.

Originally Posted by BradC

Nope, the filter runs outside -> inside. He's pouring oil in the clean side gallery which runs from the filter to the bearings.



Yeah, I can't quite figure out what the spigot actually does aside from allow a faster drain of the filter housing when you open it up, and what they've done on the 3.0 that allows it to do the same without the extra hole.

On either, I can't see how oil can drain out of the filter/gallery without air being admitted somewhere. The only sane place I could imagine air being admitted is draining back through the cam galleries. I can't see any form of "anti-drainback" valve on any of the oil system, and so I can't see how even if the spigot was malformed it would allow drainage to happen that wasn't going to happen anyway. The only issue I see with the spigot is if it's malformed or destroyed it's going to allow an awful lot of oil to avoid the filter and galleries and just drop back to the sump. But we already know that's the quickest way to engine destruction.

On the oil filter housing cap, there is a small hole in the threaded section which I presumed is exposed after 4-5 turns. This lets the air in. At the same time, the filter would also get lifted pulling the spigot up.

When I get the oil filters to change again, I will have a close look and take a picture of the cap.

There is also a blocked filter bypass, but would probably need to remove the oil filter housing and cooler to work out which way it all flows. No plans to do this……yet……

Originally Posted by BradC

If you consider putting unfiltered oil into the gallerys I suppose. Plenty of mechanics refuse to pre-fill a filter due to the risk of contamination.



From what I've been able to tell, on the 2.7 the spigot blocks the hole that drains the fluid from the filter housing back into the sump. So it's sole purpose in life is to block that hole until you loosen the housing, at which time it lets the oil drain away. How does the housing drain on the 3.0 when you do a change?

Hey Brad,

The 3.0l diesel has a hole in the bottom of the housing. When the filter is installed it pushes on a metal arm with a rubber bung mounted on it, the rubber bung then covers the hole.

I use a 4 1/2 turns to let it drain. It's enough to open to drain hole and let air into the filter for it to drain.

Originally Posted by josh.huber

Hey Brad,

The 3.0l diesel has a hole in the bottom of the housing. When the filter is installed it pushes on a metal arm with a rubber bung mounted on it, the rubber bung then covers the hole.

Perfect. So it works exactly the same way as the 2.7, just without the ability to get it wrong and lunch the motor.

I may be helpful here;

Recently removed oil cooler



Removed centre



Leaves these two open holes but interestingly C is a spring loaded plug. You can lift it up with finger nails. I’ve never heard this mentioned as this will only open with pressure behind it.



Filter sits like this in contact only partially but the spigot completely blocks the hole to A.



So filled with oil and only escape is via A B or C holes. You can see C is submerged and not leaking.



These are the holes and logically C is the one opposite A as middle one is coolant.






So I reckon C is supply from oil pump and the filter cleans from the outside with B the filtered oil return and A a drain plug. Why this is a different circuit to B I don’t know.

On that basis there is a NRV in the form of the C spring plug.

Edit: I checked and the spigot on the filter does not pass any oil. It’s purely a plug.

There are 2 unknowns then.
- Where is the bypass valve that should allow oil from C to B when the filter element is blocked?
- Is A really on the clean side? If so then removing the element would drain the entire filter housing into the oil gallery rather than back to the sump.

Note the B spigot that sits inside the filter is quite high. This is generally deliberate to ensure no un-filtered oil can get in there as the housing drains.

Interesting to note the housing has an anti-drainback valve built in.

Another possible "delay" in the oil pressure light going off after a cold start (but not a filter change) would be the time taken to pump up the hydraulic lifters. That would also explain why it doesn't happen warm.

Originally Posted by BradC

There are 2 unknowns then.
- Where is the bypass valve that should allow oil from C to B when the filter element is blocked?
- Is A really on the clean side? If so then removing the element would drain the entire filter housing into the oil gallery rather than back to the sump.

Note the B spigot that sits inside the filter is quite high. This is generally deliberate to ensure no un-filtered oil can get in there as the housing drains.

Interesting to note the housing has an anti-drainback valve built in.

Another possible "delay" in the oil pressure light going off after a cold start (but not a filter change) would be the time taken to pump up the hydraulic lifters. That would also explain why it doesn't happen warm.

I got familiar with it again today and as usual the filter housing drained some of its contents into the "V" despite the 4 turns of the housing. Aaaagh

I am sure the spring loaded part is the blocked filter bypass valve. Will only open if the filter is blocked and allow oil through.

Would need to split the housing open now to see the oil channels inside it.