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Volvo B6304 Oil Pickup Tube Repair

B6304 Engine Oil Pickup Tube O-Ring Replacement [Procedure from David Aidnik]

Symptoms: Noisy "ticking" hydraulic valve lifters caused by leakage of crankcase air past the oil pickup tube o-ring into the oil stream.

Repair: Oil pan must be removed to replace the o-ring at junction of the oil pickup tube & the block.

Parts: Four O-Rings total ($6); One Tube Volvo Chemical Gasket ($16); Oil Filter; Seven Qts. Oil

Time Required: 10 to 12 hours (first time)

Special Tools: 24 inch socket extension with a 17 mm flex joint socket. A universal joint should work, but the more compact flex socket is preferable. Dense urethane foam paint trim roller; approx 2 inch wide. I got one of these at the local harware store with replacable rollers for $5.

Step by Step Procedure:

  1. Front end of car must be elevated; front wheels need to be approx. 4-6 inches off the ground. Car must be solidly supported on jackstands.
  2. Drain coolant. Use of a short hose on the radiator fitting will allow draining directly into gallon bottles.
  3. Drain crankcase oil & put the drain plug back in. Note: Front axle crossmember must be dropped down. It can just hang from front suspension, but use of floor jack is helpful to drop it down in a careful stepwise fashion.
  4. Support engine at harmonic balancer. I used a screw type house jack and a piece of dense packing foam to conform to the shape of the balancer & keep the top of the jack located. Use of mechanical non-hydraulic jack is preferable so as to be certain that the engine does not "drift" downwards in position.
  5. Loosen engine mounts at interface with front axle crossmember. Three screw connections on each mount; two are nuts on studs & one is screw from underside of car. Remove the nuts & the screws, leave the studs for the nuts alone.
  6. Raise engine slightly using jack under harmonic balancer to confirm that mounts are lifting off the axle crossmember. Once you have this, you know that you've got the engine weight off the crossmember & can now drop the crossmember down.
  7. Disconnect the two power steering hydraulic lines from the steering unit on the axle crossmember by removing the banjo bolts; make sure to get the copper or aluminum sealing rings on BOTH sides of each fitting (2 sealing rings for each bolt). Note that the ATF/Power steering fluid is going to drain here, so have your oil drain pan handy when you remove the banjo bolts.
  8. Position steering wheel in the "straight ahead" position. This will allow easy access to steeing knuckle u-joint clamp bolts underneath. Remove steeing knuckle u-joint clamp bolt on axle end of u-joint. You will have to remove safety clip from threaded end of bolt. It may be convenient to rotate steering wheel 180 degrees to remove clip, then rotate the wheel back to the straight ahead position to remove the bolt.
  9. Carefully mark the steering u-joint clamp on the axle end & the splined shaft of the axle-mounted steering unit to enable getting these pieces back together in "exactly" the same position; a tiny line on one side & a tiny line or arrow on the other. This part is very important.
  10. Remove the four bolts fixing the anti-sway bar to the car body subframe. Two bolts on each side near the bushings at the ends. Take note of the orientation of the spacer plate between the bushing & the subframe. The anti-sway bar will just hang down.
  11. Support the axle crossmember with a floor jack under the center (it doesn't weigh very much).
  12. Remove the four large bolts (10 mm bolt; 17 mm head) fastening the axle crossmember to the body subframe. The heads of these can be easily seen on the passenger side of the engine compartment. They go straight thru the box sections of the subframe & thread into nuts welded in the crossmember. The bolts on the drivers side WILL require a flex joint type of socket & about a 24 inch extension to reach the heads without removing stuff on the drivers side of the engine.
  13. From the underside of the car, lower the axle crossmember slowly. Some jiggling loose of the steering u-joint may be necessary as well as pushing the power steering lines upwards out of the "hole" in the crossmember. This stuff around the steering should be all that is "holding" the crossmember from dropping down. Once the splined shaft comes out at steering u-joint connection, the crossmember should just drop down about 8 inches. It doesn't fall because there is a lot of friction in the rubber bushing connections in the axle & steering. Pull the crossmember down as far as it will go. Now you have the working clearance to get the oil pan out.
  14. Remove the oil filter housing/oil cooler. This has one very large banjo bolt (42 mm head). This must be removed as one of the oil pan screws is INSIDE it and another is under it!
  15. You are now ready to begin removing the oil pan bolts. Note that the bottom three bolts in the front mount of the transmission to the engine are threaded into the oil pan. You will need to take these bolts out, so you should support the transmission somewhere near the front of the pan. I used a hydraulic floor jack (the one I no longer needed under the axle crossmember) & just jacked up enough so that I saw the back of the engine start to move upwards. Then I knew that I wouldn't be stressing the transmission/engine interface too much when I took out those bottom three bolts. Remove these three large bolts.
  16. Now loosen all the small bolts attaching the oil pan to the engine (10 mm hex head). There are some at the back where access is not easy. I used a general loosening pattern of loosening the perimeter ends first; working toward the center & loosening the center ones last. If all the bolts are loosened, the oil pan should crack loose and now your almost done with the diassembly. There are a few different lengths in these bolts, about 75% are all short approx 1 inch & identical; the other 25% are longer & varied in length. I marked the position of each of these longer ones on a couple of sheets of paper and put these bolts on the paper to keep everything straight.
  17. The oil pan comes out towards the back & off to the driver's side; it can't go straight back because of the jack under the transmission. Remove the pan, pour out the residual oil & rough clean it with something like paint thinner & an old toothbrush; NO wire brush, steel wool or abrasives allowed here. The baked-on varnish-like oil is not a problem. Remove the plate attached in the oil sump area to enable cleaning of any crud here. There are lots of corners because the pan has internal buttresses to add stiffness to the block when assembled.
  18. Zen and the art of using a single edged razor blade is what the next phase can be called. This is where you CAREFULLY shear off every square millimeter of the chemical gasket material, which should be almost all on the oil pan. This process will take maybe 1.5 hours; you don't want ANY gouges in the sealing surfaces of the aluminum pan or the block; this stuff is only maybe 5 mils thick or less. After you finish the pan, you can check for any remnants on the bottom of the block after you remove the oil pickup tube. When you see the shape of the oil pickup tube, the weird "jock strap" protrusion in the front of the oil pan makes a lot more sense.
  19. There are two o-rings on the bottom of the block which you should/will replace. There is also one on the oil dipstick tube. After the razor blade cleaning, wipe off the mating surfaces with a non-greasy solvent to make sure the mating surfaces are impeccably clean. I had to wipe out some of the oil in the cavities where the main bearing bolts were as oil kept oozing out onto the mating surface of the block.
  20. With everything perfectly clean, you are ready to reassemble. Put the plate back in the sump area of the oil pan. Re-install the oil pickup tube with a new o-ring. When I put this in, I noted that the new o-rng was significantly tighter than the old o-ring. The o-rings on the bottom of the block can be tricky. Gravity is against you here & you don't want them falling out as you try to put the pan on. I used some of the chemical gasket stuff in the counterbores of the block where the o-rings go. Put a little bit in; put the o-rings in & let them sit a little while you continue to make sure they won't fall out later at an unwelcome time.
  21. Now in the re-installation, you must get the prepped pan under the car without touching or getting any dirt, etc on the prepped surface. You must also get it angled up a bit in front to clear the axle crossmember without touching or scraping anything on the sealing surface. I did a trial run at this time before prepping the pan with the chemical gasket, just going to the point where I was ready to push the pan up on to the block and no further as I did not want to disturb the two o-rings on the block which were still sticking in the chemical gasket stuff. So far; so good. I took the pan back out for the final prep.
  22. Apply the Volvo chemical gasket to the oil pan. I put a bead all the way around & used the 2 inch wide urethane foam roller to even it out. The roller really helps to get the chemical gasket coat thin but even; that's the way it works best. I touched up the amount wherever it needed it so that I had an even thin coat; there is at least 1.5 times as much as you need in the one tube of the chemical gasket material. Note: This also brings to mind a dilemmna I faced at this stage in putting the pan back in. There is a crankcase breather tube fitting on the driver's side of the pan which makes it pretty difficult to get access to a screw or two on the perimeter of the pan at the back. In re-installing the pan, I figured to leave this tube off until after I got the pan back in. I discovered later that the hex on the breather fitting proved quite difficult to access as well after the pan was in. I put some of the chemical gasket material on the cleaned threads of the fitting and screwed it in as tight as I could by hand. Then I managed to get it turned maybe a quarter of a turn afterwards with great difficulty. The gasket goop seemed to set, and I put a better hose clamp on the fitting to prevent any turning. A deep socket should have worked, but the cylindrical part of the fitting was too big to fit in the bore of the deep socket. . . You decide your best approach on this one.
  23. Now the pan goes in for real. Be sure to have the four center screws for the pan handy down there as well as a 10 mm socket driver that you can manipulate with one hand only. Two screws in the mouth, like a carpenter with nails, socket driver ready; one last look at the two o-rings on the bottom of the block; this is it! Clearing the front mount of the transmission with the back of the pan is the last hurdle, then up & back against the transmission at the same time. Hold tight & get two of the center screws in & hand snugged so the pan cannot pull back away. Now you can breath; it's almost all downhill from here.
  24. Get all the oil pan screws back in & just snugged including the special lengths. Install the 3 bolts that anchor the transmission to the oil pan & just snug these as well. The spec torque of the oil pan screws is 15 ft-lbs. I tightened in a general pattern fron center-middle to perimeter-ends in a couple of stages. After the first stage, I tightened the 3 transmission bolts about halfway as well. There are about 50 screws in this oil pan. Get all the screws & bolts torqued. The bolts from the trans into the oil pan should be tight; 40 ft-lbs. Floor jack inder the trans can now be removed.
  25. Re-install oil filter housing/oil cooler. I used a little bit of the gasket sealant at the top with the neoprene gasket. Put a new oil filter on.
  26. Re-installation of the axle crossmember & anti-sway bar is pretty straightforward except that is must be taken stepwise with the floor jack to get the splined steering unit shaft engaged in the delicate aluminum clamp (which is easily damaged) in exactly the right rotational position and keep from pinching either of the power steering lines under the motor mount on the driver's side. Tighten axle crossmember bolts 70 ft-lbs. Fasten anti-sway bar to subframe.
  27. Get steering u-joint bolt back in & tightened. Don't forget the safety clip. Get power steering lines connected to axle mounted steering unit with the banjo bolts. Don't forget the copper sealing rings on both sides of the fittings.
  28. Get the nuts & bolts back in the engine mounts. Don't forget to get the clips which anchor the power steering lines under the motor mount nut on the driver's side. Lower the engine down on to the axle crossmember & tighten the motor mount nuts & bolts.
  29. Get the coolant back in the engine. Put about 6 qts of oil in the engine. Remove the spark plugs; cover the plug area of the head with the plastic cover (coils off to the side) & crank engine with the starter until you get oil pressure. This takes a bit of cranking as you have to fill up the new oil filter. I took this in a couple of steps; the oil light icon DID eventually go off.
  30. Re-install spark plugs & start motor. Go back under & look for any leaks. Keep pumping (squishing) upper radiator hose to get air out of coolant system.

The ticking of the hydraulic lifters didn't disappear right away, but was less. After I got the plastic covers on the underside; got the back on the ground & drove the car, I drove it in Low for a few miles around town with some periodic accelerations especially in the 4000-5500 rpm range. This pumped out all the air from the hydraulic lifters and the car ran "so so so sweet". Only then did I realize how much the air content in the valve lifters caused assymmetry in the valve openings; before the o-ring replacement, I could feel that assymmetry in the exhaust stream at the tailpipe with my hand; it was subtle, but it was there. The car will run with this condition, and will run reasonably well, but will NOT run "RIGHT". After the job, the exhaust stream at the tailpipe felt like sweet perfection. This engine was at 112k miles

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