- The issue of FRONT cam seals leak has been discussed too many times in different forums. After doing this job, you will understand why dealers charge $1000+ for this job, read on…
- I am working on a 2007 S60 2.5T with 115K miles, no cam leak yet but my 2005 XC90 2.5T with 125K miles (TB was done at 110K) is leaking from FRONT cam seals. Now I learn the lesson that at 110K-120K, if you ever do the TB job, replace the cam seals while there. But it is more complex than that, maybe the excessive play of the Exhaust VVT Hub contributes to the oil leak.
I am doing the TB on the 2007 S60, so I may as well replace the front cam seals (and rear cam seals) since I am there anyway.
- Before doing this job, remove the TB covers and run engine briefly to see if the TB walks in and out or not, just to get a baseline feeling of how things are. You may want to record a brief video for the purpose of comparison later. Some worn-out VVT Hubs make noise. This way after you installed the new VVT Hub and cam seals, you can compare the difference.
- There are 3 separate issues:
1. Oil seal brand and installation technique. I use Corteco.
2. VVT, especially after 120K, can move enough axially that even with new seal, it may leak if you are not careful with the seal installation (read on). At 115K miles, my VVT Hub has an axial play of 1.7 mm. Brand-new VVT Hub has a play of 1 mm. From reading different forums, by the time the VVT Hub play is 3 mm, there is a good chance it will leak, even with new cam seal. So, if you have more than 130K, you may as well replace the Exhaust VVT Hub, and hopefully you only do this job once.
3. VVT Hub indexing: with VIDA instructions close to worthless (1 cog, 1.5 cogs and all that blah blah blah), and most of youtube videos on Volvo VVT hubs show a lack of understanding of the engineering aspect of VVT. Many youtube videos are misleading and inaccurate, therefore I will attempt to consolidate all these issues in one DIY.
- Also, the pdf by @F250 is somewhat confusing (despite his nice attempt to write it). I personally ignored his pdf, I found it difficult to read and unnecessarily complicated.
- The way to understand the Volvo VVT Hub engineering design is to ignore VIDA bc VIDA instructions for the VVT system are so bad.
- In contrast to other car mfg’s that index the VVT Hubs, making installation a breeze, Volvo does not index (key) the VVT Hub. Instead, Volvo decided to use the T55 bolt and 88 ft*lb! No big deal. The T55 bolt is for “coarse adjustment”, and the 8-mm bolts oval slots are there for “fine adjustment”. Think this way: during operation, the rotating force goes from:
TB ---> Toothed Sprocket ---> 8-mm bolts (mated with Outer Hub) ---> turning it CW ---> Inner Hub (which is mated to camshaft via the T55 bolt)
- Let’s say during installation, the T55 bolt turns the hub a bit, maybe 2-3 mm past the mark, you can always do the “fine adjustment” via the 8-mm bolts. This is why you leave the 8-mm bolts in the middle of the oval slots, just in case you need to adjust it.
BEST is to install the VVT Hub about 2-3mm just to the left of the timing mark, slowly tighten the T55 bolt with the RH while the LH keeping the hub rotated to full CCW to counter the rotation. Rotate the Hub back and forth to verify timing mark between tightening sequence. During tightening, it will move a bit to be just about right. I found out after 25 ft*lb or so, the timing mark did not move any longer as I tightened the T55 bolt. Go slow in increments and do not tighten to 88 ft*lb until you are happy.
- Whatever you do, once said and done, you should rotate the VVT Hub back and forth CW and CCW; in full CW position: it must match with timing mark.
- Another way to understand the VVT Hub design is: The Toothed Gear is mated to the Outer Hub via the 8-mm bolts, and the camshaft is mated to the Inner Hub via the T55 bolt. The Outer Hub rotates CW and CCW. During engine operation without the VVT activated, the Blue dot lines up with the Red dot in my diagram below. When oil P is pushed inside, the piston inside the VVT Hub is pushed outward and thus translates the linear motion of the VVT piston into rotational movement of the Inner Hub, turning the camshaft CW to advance it. This is bc the VVT Toothed Gears and Crank
Sprocket have a fixed relationship dictated by the TB teeth. Think of the VVT Outer and Inner Hubs rotating w.r.t. each other.
If you think like an engineer, it will be clear: when you turn the Outer Hub full CCW (engine off w/o the TB installed), the camshaft is effectively in an advanced position. And that is for testing w/o the TB installed. Once the TB is installed, you cannot turn the Toothed Gear CCW, the only way to advance the cam is via the oil pressure feeding the VVT, turning the camshaft CW into the advanced position.
- Volvo-VVT-Leak.jpg (41.04 KiB) Viewed 16416 times
- You need to be familiar with the Volvo 2.5T TB job first. I wrote an extensive DIY on my 2005 XC90 2.5T here.
- If this is the first time you replace the cam seals and VVT, make sure you read through the TB DIY first.
If you are coming from P80 (1993-1998 850 and S70, V70), then this will be easy transition if you read a bit on VVT Hub engineering. Please note that I updated that DIY to route the TB during installation clockwise, it is much much easier that way…
---> DIY: 2005 Volvo XC90 2.5T Timing Belt, Water Pump, Serpentine Belt
viewtopic.php?t=83521
TOOLS:
- Serpentine Belt Tool is a must. It is inexpensive at Harbor Freight or ebay.
- The thin-profile levers (3/8” and 1/4") made the job much easier bc you don’t have to remove other parts to get to the rear cam seals etc. The Powerbuilt tool is a great helper.
- Metric wrenches, Torx set (for cam sensors) and Hex metric set (Hex for the TB tensioner).
- For the VVT Torx #55, I bought the 1/2" type. Forums told me 3/8” type T55 is also fine.
Since this is going to 88 ft*lb, I use 1/2” type. After I did the job, I also bought the 3/8” T55 socket, I should have bought this too. The difference of 6mm between the 3/8” and 1/2" socket makes a huge difference. The 3/8” T55 is good for the cap, and the 1/2" T55 is good for the big center bolt. Or you can buy just the 3/8” T55 for the entire job.
- FYI…A 1/4" drive can take about 30 ft-lb, 3/8" about 100 ft-lbs, 1/2" about 230 ft-lb in normal operation. The 3/8” drive breaks about 150 ft-lbs, 1/2" about 300 ft-lb.
- You need the 1/2" 30-mm socket + long extension to spin the crank gear.
- Liquid Paper, Sharpie pen to mark VVT hubs.
- PVC couplers, some plumbing adapters (read on), mirror to see better.
- Of course, you need the floor jack and jack stands (please see the DIY XC90 2.5T TB for detail of jack points).
- Cam locking tool: search forum for home-made stuff, but my advice is to use the CTA tool ($110) bc it seems better than EWK ($50). By using CTA tool, less risk of damage. You can always sell the CTA tool later on ebay once done or if you no longer own the P2 cars.
PARTS:
- Good source is FCPEuro etc. I bought most of my parts from FCP. The Exhaust VVT Hub was on sale Ft Washington, PA Volvo dealer for $215 with free shipping.
- Cam seals: the FRONT cam seal is definitely Corteco. When placed side by side, the Volvo factory seal is identical to the Corteco (Corteco ground off some numbering system on the seal surface to avoid issues with Volvo). The REAR cam seal: I do not know who made it for Volvo, but my experience using Corteco for the rear cam seals has been excellent.
- TB Kit: I have been using Continental for yrs. Conti is the orig mfg for Volvo TB. Inside the Conti TB kit is INA pulleys.
- Serpentine belt: I use INA pulley and Conti belt. The 2007 S60 uses a shorter belt than let’s say 2004 model (smaller PS Pump pulley diameter in the 2007 S60).
- At 115K, the Intake VVT is still good with minimal play. The Exhaust VVT was still OK with about 1.7 mm radial play (no oil leak at 115K yet) but since this is such a big job with tons of potential issues, I elected to install a new VVT Hub bc I don’t want to do this job again.
PROCEDURE:
I must say after doing this job, the car runs fine, probably more acceleration bc of the new VVT (maybe it is all in my head lol). No oil leak.
I leave the TB covers off for a week while checking for oil leak. So far so good. Before VVT Hub job, the TB “walks” 0.3 mm in and out during engine operation, still within spec @ 115K miles. After the new Exhaust VVT Hub: zero walking of the TB, perfectly straight during engine operation!
After the VVT job, car threw a code P0026 (Intake Solenoid) presumably from not enough oil pressure building up after the job. I erased the code P0026, never came back. So if you do this job and have the P0026 or P0027, just relax a bit and erase the codes to see if they come back.
The thing about this job is during installation, go slow and be methodical, do NOT torque anything to specifications until you are happy with the VVT indexing. For example, the 8-mm bolts: just snug them to about 4 ft*lb instead of 8 ft*lb. Only after you are happy, then go to 8 ft*lb. Same is true for the big T55 center bolt, go to ~ 25 ft*lb, which is enough for testing the VVT Hub CW and CCW. Then go to 40-50 ft*lb and check again. Only after you are happy, then go to 88 ft*lb. I found out after ~ 25 ft*lb, the VVT Hub index mark does not rotate any longer as I tightened it further.
1. Parts as shown, serp belt tool, and thin-profile levers (3/8” and 1/4"), CTA Cam Locking Tool:
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2. PVC Couplers etc. with Cam Seal. Note old hub with 115K (no oil leak) has a groove from millions of rotations with the sealing edge of the seal creating a groove. If you re-use the old hub (i.e. budget issue), then make absolutely sure the new seal sits exactly as factory, more later.
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3. Use Permatex Black RTV around the OUTER edge of the seal, so it has less chance of coming loose.
Wet the inner lip of the seal with oil when inserting the new VVT Hub. Permatex Black RTV package says it takes 24h to cure. So best is to do this job on let’s say Saturday but don’t start the engine until Sunday.
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4. The VVT Hub 8-mm bolts is M6 x 1.0 type. Torque is 8 ft*lb. I use Red Loctite. When transferring the
Tooth Sprocket to the new VVT Hub, just use the factory setting to start where to place the 8-mm bolts.
If you ever strip the threads, either on the bolt or the VVT Hub, do not panic, just get a small M6 x 1.0 nut and install it with Red Loctite. I did not touch the Intake VVT but no idea why Volvo designates a different torque for Intake VVT (maybe 10-12 ft*lb).
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5. Timing Belt, Serp belt and Pulleys.
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6. Engine photo so you can see where the bolts are. Note that I use the minimalist approach: unclip the Air Filter Cover and loosen the clamp as shown, this allows you to move the big plastic tube (removing this big plastic tube is a pain, so I avoided it) sideways, then tie it with a string to keep it away. This way you can use the thin Powerbuilt tool. I guess the serp belt tool works here too bc it has a low profile.
NOTE: the Intake Cam Sensor holes where the bolts go, I missed this part and inserted the bolt in the wrong hole on the top lol. Took 15 min to find out where it should go…
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7. Once the cam sensors are off, use 10-mm socket to remove the Reluctors. This is why you leave the TB alone until now to avoid moving the camshaft.
NOTE: Intake vs Exhaust Reluctors are different, label them to be sure but it is not necessary bc if you look in the back of the Reluctor, they have different indexing tabs.
NOTE: the force of removal will break the tiny little tab on the end of the Intake camshaft. No consequence here at all bc the Reluctor will reinstall just fine (install this bolt ONLY after TB is re-installed). However, you might want to insert a tiny woodruff key in that space to avoid the damage to the little tab. I use Red Loctire during installation.
- CTA tool came with no washers, I used some washers on the bolts. TRICK: when rotating crank to get to timing mark, stop the crank about 1 inch before the timing mark, then moved it very very slowly 1-2 mm at a time while checking the rear to see if the Locking Tool fits, just snug them loose and slowly tighten them.
Only when you are happy with the setup, then tighten the bolts, I just snug them then tighten a bit, no need for excessive force, I am guessing 12-14 ft*lb.
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8. Once the rear side is good (Cam Locking Tool in place), go to the front, the CRANK long mark (use the long mark on the crank, much easier to see than the tiny marks) should line up, as well as the VVT Hubs.
If you look at the DIY TB I wrote in the link, I marked behind the VVT Sprockets (on the engine side), it made it much easier w/o the need to re-install the TB cover to verify timing marks.
NOTE: During installation, I used the Clockwise approach to route the TB, it is much easier this way bc the TB keeps the VVT Hubs in full CW direction. Just follow the sequence in the Orange color: 1-2-3-4-5-6, i.e., the TB slides on the Idler Pulley last. Don’t forget to tighten the Tensioner Pulley (using the 6-mm hex key to adjust at the same time), the tensioner pulley is such a critical bolt, I used Red Loctite here.
Routing the TB CCW way is cumbersome and wasting time, I found out CW is better after 1h fighting with the TB doing the CCW way!
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9. To disconnect the coolant level sensor connector, there is a tiny tab, use the small flat screwdriver to gently loosen it. To prevent fluid loss, cut a “finger” off the rubber glove + rubber band as shown. I also used some cardboard as cushion to prevent the Sprocket from rubbing the hoses (coolant and PS hoses).
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10. Space was tight, so a 10-mm wrench may help. Or use serp belt tool. Since I did not have the 3/8” T55 socket, I had to use this setup lol… In retrospect, I should have bought the 3/8” T55 socket.
TRICK: use a zip loc bag underneath to catch the oil leaking out.
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11. Tie the coolant reservoir away. Note I had to use an iron pipe to undo the T55 bolt. This is when you will likely break the small little tab on the end of the camshaft on the rear side. See note above.
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12. The seal exact spot was discussed in the thread link below. This is a must-read if you don’t want to do this job twice! Note that the factory design was poor: the bore side of engine was a little loose and the Corteco seal can be installed just by hand and it has a tendency to fall off with time (search forum, there are tons of threads on this), I used Permatex Black RTV as mentioned above.
Cause of intake cam seal leak?
viewtopic.php?t=82864&start=10
13. Here is the factory setup, note the cam seal sits at the very edge of the chamfered edge. I used the PVC Coupler + Sharpie mark, it makes installation check very easy, you are talking 0.5 mm here and there! When you install the VVT Hub, oil the outer shaft first, you will hear a distinct “pop” when the VVT Hub is fully inserted: this is the sound of the sealing edge popping back onto the VVT Hub shaft.
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14. If you ever push the seal too far in, such as 1 mm too deep, no worry, use a pair of right-angle pliers to gently pull it back out. Note I use a small piece of cardboard as cushion on the camshaft sides.
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15. The REAR cam seal: as mentioned many times in forum, I used a small punch, then inserted a screw dead center to remove it. Do NOT damage the shaft side! I happened to have a plumbing adaptor as shown, this device was perfect for installation in the tight space!
- Volvo-VVT-33.jpg (131.52 KiB) Viewed 16416 times
16. For Front Cam Seals, the Engine Bore depth is 7 mm, Seal size is 51 x 65 x 7mm. You can see the old seal is getting tired with sealing edge being dull. The new sealing edge is sharp…
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17. Brand-new Exhaust VVT Hub moves in and out axially 1 mm between CCW (cam advanced) and CW (cam retarded). Note the Range of Movements of Exhaust vs Intake VVT Hubs in terms of degrees.
My guess re wear and tear is that: the Exhaust VVT is activated more frequently, thus the wear at 115K.
The Intake VVT probably does very little work during engine operation, thus almost no wear at 115K miles. I do not have the engineering spec’s of angular rotations of Intake vs Exhaust VVT Hubs, but the photos showed what I found…
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18. Some photos of the cutaway view so you can see the way oil flows through the VVT pushing the piston outward, in the process of doing so, the INNER gear is rotated CW, thus advancing the cam.
The cutaway view is courtesy of @jimmy57:
- Volvo-VVT-Leak.jpg (41.04 KiB) Viewed 16416 times
- Volvo-VVT-Seals.jpg (148.48 KiB) Viewed 16416 times
Thank you for reading this. You will be happy with new Exhaust VVT Hub and Cam Seal.
Of course, double-check, triple check all nuts/bolts and manually rotate the engine crankshaft x2 using the 30-mm socket before starting the engine.
When in doubt, check again before firing up the engine!
Once you are happy with everything, say a quick prayers and fire up the engine…
PS: “Enjoy” this Volvo job while it lasts, newer engines use timing chain and there is none of this non-sense. All this happens bc of the timing belt design inherent in older Volvos, Hondas, Toyotas etc. My 2004 BMW 325i M54 engine runs on timing chain, which is concealed and timing chain lasts some 300K; also there is no such thing as BMW cam seal bc the timing chain is inside a cover and bathed in oil. The BMW Vanos does not ride on a cam seal. Overall, the BMW design for VVT (Vanos in BMW) is superior, from an engineering standpoint. Anyway, TB design is the yesteryear stuff, soon or later, it is going the dinosaur way, so “enjoy” this job while it lasts lol…
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