NA oil filter housing leak: seals, torque and the tool

Why it leaks

One owner explained it in 2011 with a diagram that didn't survive in our copy, calling the parts A to D. In his account: the filter cap (A) should only need to be nearly finger tight, because it seals with its rubber O-ring. Under it is the oil cooler adaptor (B), which should be tightened once and never move, and which sits on two thin metal seals (C) either side of the cooler sandwich plate (D). The oil in that part of the engine is at full pressure, up to 130 psi, so a leak there floods out.

• The adaptor needs 120 Nm, according to one owner, which can't be reached without the dedicated GM tool. Without it the only way to tighten it is by using the cap, which then makes the cap and adaptor one unit.
• The cycle. Once someone has tightened the adaptor via the cap, the whole thing comes out when you undo the cap. The two seals are one or two use only, because they have a crushable ridge, and are easy to nick when you refit the adaptor, which causes a new leak. So the next person over-tightens it further, and so on.
• Dealers. One owner said a lot of Vauxhall dealers don't have the tool either, which is why so many cars have the problem: the dealers create it. Another owner rang three VX220 specialists and only one had the tool; the other two said they just use wrenches.
• Other engines. One owner said it is VX220 specific: the Astra and Vectra have a plastic version of the cap that screws straight into the housing on the block.

Getting the adaptor out

• One owner (2011): you don't need to remove the cooler pipework from the sandwich plate. He and a friend used a big Stillson wrench to hold the edge of the adaptor gently and loosen it, then unscrewed it by hand and lifted it out of the housing. Access is "a total pain" with the engine in the car.
• On his first engine he undid it with a big flat screwdriver in one of the notches around the edge, tapping the end with a hammer. He said be careful.
• One owner used monster water pump pliers and had no leaks, but they left slight grooves on the sleeve. He suggested an appropriately sized C-spanner might do.
• Anarchy (2012) tried a bike-chain type filter tool and couldn't loosen it, and planned to try again once the manifold was off.
• One owner's adaptor had been wrecked by previous attempts, with the flat sides where the seals sit damaged and the tool notches battered. He asked whether the parts were available. Another owner replied in 2012 that he thought they were still on back order with GM, and that AtomX had a few spares.

Seals

• Supply. In January 2011 one owner ordered them from Vauxhall as a special order. Another owner heard that AutoVaux had nearly 300 in stock. In 2009 a third owner said they were a couple of pounds from AutoVaux, and in 2010 a fourth owner's local dealer took about three weeks, and a fifth owner found AutoVaux on back order. These are historical notes on supply.
• Which seals. By 2026 owners were using aftermarket sets. One owner bought Type116 Motorsport Z22SE oil filter seals, which he described as two numbered metal gaskets with a rubber compound on them. Another owner said he has OEM ones and that aftermarket seals are a little more sensitive to torque. He also said plenty of owners had managed with the graphite ones. Owners were not agreed on graphite versus metal seals.
• Fitting method that worked in 2026. His first attempt leaked because the bottom gasket kinked on the threads: it was sticky going in and was chewed up when he took it out. For the second attempt he followed the tech documents, which he said state to install the gaskets smooth side down. He oiled them, checked with a fingernail that they slid over the threads, pulled the bottom gasket up against the cooler ring, screwed it down easily by hand, and then torqued it to 110 Nm. He also cleaned some of the rubber compound off the bottom gasket so it went on without catching. There was still a very small leak in April, so he gave it a further nip-up, which cured it. He said it needs to be "very tight". One owner warned to have spare seals ready before disturbing it, and said the cap torque must also be the book value, because over-torquing the cap tends to move the ring.
• Earlier fitters. One owner (2010): refit the two black metal gaskets carefully so you don't trap them on the thread, tighten by hand finger tight first, then properly with the socket or extension, run the engine hot and give a second tightening while warm. He also said that after a fix he pinched the lower O-ring on his first try. Another owner said his leak was round the sandwich plate and tightening it "good and tight" stopped it.
• Sealant. One owner used Hylomar to help seal. Another owner used a Hylomar-type sealant with new gaskets and said it seemed to lock the cooler pieces permanently in place, so he could then take the cap off for the filter change as intended. A third owner put flange sealant around the seals, and a fourth owner got the impression it worked well. Another owner saw the locking effect of his sealant as a bonus.
• Don't wait. One owner said don't mince around waiting to see what happens: order the gaskets and replace them. A leak from the housing can lose a lot of oil quickly (another owner lost 2 litres of new oil after a service).

The tool

• The GM tool. One owner posted a photo of what he called the proper tool for the adaptor insert. The file name in his link suggests it is GM KM-6264, but that is inferred from the picture and is not checked. The only price he could find was 435 (the currency symbol was lost in our copy). He said that at that price he would rather abandon the housing and fit a remote filter using an adaptor from the States. By 2012 he had dropped the idea, expecting a Saab engine to use a different cooler set-up.
• The cap socket is a different tool. The 32 mm socket sold for the filter cap is only the straightforward bit for the cap (one owner to another owner, whose link was to that).
• Borrowing one. In January 2011 Eden Vauxhall in Newbury lent one owner their tool for a deposit of £150, and one owner's dealer lent his for free. One owner said the one he borrowed was nothing like another owner's picture: a circle with notches that fit the slots on the canister, with a small handle, and the only way to get decent torque was to hit it repeatedly with a hammer, which he called useless.
• A group buy that never came. One owner offered to get one made by a friend who has CNC access. By February 2011 he said the price would depend on how many people wanted one, with something like £300 for one, £400 for ten or £500 for fifty. Owners said they would pay up to about £25 to £40. Another owner suggested cutting slots and fitting drive keys. By March nobody had a price, and no tool appeared in the thread. A shared "pool tool" was also suggested.
• Homemade (2012). He had a laser cutter make three rings, welded them together, filed the teeth to an angle, and then welded on a top hat with a 1/2 inch socket drive. He said it worked a treat and told others to copy it. He ordered ten more for the forum, but at the time of the post they had not been made.
• Type116. In 2026 one owner used the Type116 ring spanner with extension bars on a torque wrench, and said the torque wouldn't be very accurate that way.

Putting the owners' accounts together

1. Make sure it is the housing (see the finding guide). Clean the area.
2. Have the new seals and a spare set ready before you start. Don't rely on a dealer having them.
3. Separate the cap from the adaptor with the tool you can get hold of (a ring spanner, a homemade ring, or a loan from a dealer). Don't damage the sealing faces on the adaptor.
4. Fit the seals oiled and smooth side down (one owner's reading of the tech documents), and make sure they pass over the threads without kinking. Screw the adaptor down by hand first.
5. Tighten the adaptor with a tool that doesn't use the cap, to the figure in the TIS. The figures owners reached were 100 to 120 Nm, but not everyone had a torque wrench that fits.
6. Fit the cap with its O-ring and tighten it only to the cap torque, not harder. Run the engine, check, let it cool, and check again, then re-check hot.

That last list is our summary of what the owners did, not a manual procedure. The TIS figures quoted are from posts, so check them against your own TIS.