timing belt, water pump, & cam Q's [2.5L SOHC]

[porcupine73]

Hello, I have some questions about changing timing belt and water pump (this is my first time doing work of this magnitude)

 

• 2000 Subaru Outback 2.5L SOHC 4cyl gas non-turbo
  
• Crank is set at #1 TDC (compression stroke)
  

Engine layout is (according to OEM manual):

#3 #4

RH LH

#1 #2

radiator

 

The story so far: In the process of removing the timing belt, the LH cam rolled backwards about 30 degrees, so I rolled it forward back to where it was.

 

Then, I had to remove the LH cam pulley to replace the water pump, and in the process of doing that, the cam rolled forward about 30 degrees.

 

I'm trying to determine if I might have damaged any valves from the LH cam moving. Someone told me that when #1 is at TDC on compression stroke, that #2 is at TDC on the exhaust stroke, which has me worried, as in did the valves plow into the #2 piston when the cam rolled? [it is my understanding from EndWrench.com that on the 2.5L engines, the valves can hit the pistons; is that true?]

 

When I install the new timing belt, I'll have to get that cam back to its original position, so should I turn it forward about 270 degrees (maybe I can't roll it forward if any valves touch #2 piston) to get back to the original position or is it OK to roll it backard?

 

I didn't see anthing in the service manual about being careful not to roll the cam when removing the cam pulley bolt or when removing the timing belt, so I'm _hoping_ that no damage was done (i.e. neither #2 nor #4 are near TDC and/or the valves can't interfere with the pistons). I mean, the OEM manual seems to be pretty careful to point out in big bold print every little thing that could possibly cause damage. EndWrench clearly says the cams must be locked on the DOHC version when removing the timing belt.

 

Anyway, I guess if there's any risk I damaged something, then maybe I'll do a cylinder leakage test on #2 as EndWrench says to see if any valves might be bent or nicked. I told a friend who builds race cars that and he said it might be hard to tell because with the engine cold there might be leakage around the rings. He also said that unless I really plowed the valve into the piston with a lot of force they might have touched but not done any damage.

 

Thanks in advance for all your help! Louis :-)

[idosubaru]

others here will know better but i wouldn't expect any damage from that. those cams are quite snappy though. with a leakage test i think air would blow past a bent valve way faster than it'll leak through the rings. i think that would be obvious.

[porcupine73]

Thanks for the info grossgary.

 

On a related note, is there anything else I should consider replacing while doing the timing belt & water pump, such as the cam seals, crankshaft seal, oil pump o-ring, resealing the oil pump [i think the 2.2L had an issue with the oil pump bolts coming loose?; don't know if that applies to the 2.5L also]? I'm at 105k miles now [00 Outback 2.5L SOHC]; bought used at 96k; don't know previous service history.

 

So far I'll be installing all new OEM: timing belt, tensioner, and all idlers [should I replace the cam sprockets too? only about $30 each]; water pump, heater hoses, radiator hoses, thermostat.

 

Thanks again!

[Wayne Boncyk]

grossgary's right -- there is no issue with those cams snapping out of position while you have the old belt off, PROVIDED you aligned all the timing marks per the Subaru instructions (which places all the pistons enough off of TDC to make contact with a valve impossible). That's the only way I've done mine in the past, and even though I've had the cams snap off of their lobes as you had, no damage has been done.

 

I can't speak to what may happen if you don't align all the marks prior to removing the belt -- I imagine that there may be a configuration where a valve could be whacked against a piston, although I can't picture a situation where that would happen. More likely is that someone would, in a panic after the valve snapped shut, turn that cam in the wrong direction, which would potentially do some damage.

 

Anyway as long as you're in there, I'd do all the other things that you suggest, with the exception of the oil pump bolts since they are an issue only for the 2.2s. There is never a time NOT to replace seals on this engine , and even though it is early, the cost of a replacement water pump is cheap insurance.

[Wayne Boncyk]

...as for cam sprockets, they don't seem to be needed in my 2.5 even after 215K miles. I think you'd be OK skipping them this time, with so few miles on your engine.

[hohieu]

Thanks for the info grossgary.

 

On a related note, is there anything else I should consider replacing while doing the timing belt & water pump, such as the cam seals, crankshaft seal, oil pump o-ring, resealing the oil pump [i think the 2.2L had an issue with the oil pump bolts coming loose?; don't know if that applies to the 2.5L also]? I'm at 105k miles now [00 Outback 2.5L SOHC]; bought used at 96k; don't know previous service history.

May as well check all these things while you have the front of the engine apart. Permatex ultra-grey seems to be the gasketmaker of choice, and use some medium loctite (blue) on the screws. Be careful not to scratch the cam/crank shaft ends when you do the seals -- a little oil on the ouside circumference and moly grease on the inside lip also helps.

 

 

 

So far I'll be installing all new OEM: timing belt, tensioner, and all idlers [should I replace the cam sprockets too? only about $30 each]; water pump, heater hoses, radiator hoses, thermostat.

Thanks again!

You're really playing it safe. Usually only the toothed idler goes. You could inspect the other two and if all is well, you could save the new ones for the next time around. Same could be said for the tensioner. Heater and radiator hoses tend to last quite a long while. If they're not soft and and spongy, you might want to wait a couple coolant changes before replacing all the rubber. Also remember to dump that Subaru coolant conditioner into your cooling system (recall WWP99) -- subaru's preventive for external headgasket leaks -- which also seals any stubborn leaks around your cooling system fittings. You might want to go to mysubaru.com and check to see if there are any open recalls on your OBW. Cam sprockets are fine unless they're excessively worn or scarred.

 

As for your removal of the cam sprockets, next time you might want to crack the cam pulley bolts before removing the old belt to save you the hassle of having them move.

 

Good luck.

[porcupine73]

Thanks so much for the info Wayne and hohieu. That helps a lot. I feel more at ease now. I did have all the timing marks aligned per the manual before I removed the belt.

 

hohieu, just to clarify, when you say Permatex ultra-grey, do you mean the ultra-grey RTV type sealant, or do you mean that Permatex grey non-hardening stuff? Thanks! :-) Good point on the cooling system conditioner, I'll have to pick some up at the local dealer I saw they had it on display, or would maybe Bars Leaks or something be just as good?

 

Say, how do you guys break loose the bolts on the crank pulley and cam sprockets? I don't have that Subaru special tool so I cut the old accessory drive belt and timing belt and wrapped them around the pulley and LH cam sprocket respectively, then used a huge chain wrench from Harbor Freight to hold the pulley/sprocket while using a socket and breaker bar. It worked fine on the crank pulley, but I think I might have deformed the LH cam sprocket from the force of the chain wrench.

 

Thanks for the mysubaru tip; I checked that right after I got the vehicle and there were no open recalls (at that time anyway); the recalls that were performed were front oxygen sensor replacement and cooling system conditioner installation.

[hohieu]

hohieu, just to clarify, when you say Permatex ultra-grey, do you mean the ultra-grey RTV type sealant, or do you mean that Permatex grey non-hardening stuff? Thanks! :-) Good point on the cooling system conditioner, I'll have to pick some up at the local dealer I saw they had it on display, or would maybe Bars Leaks or something be just as good?

Subaru recommends anaerboic type sealant, but the ultra-grey RTV type sealant works fine -- just don't overdo it. That Subaru goop seems to work quite well in sealing small leaks with no adverse effects on the cooling system -- . Some dealers really jack up the price so you might want to check online for better (Part# SOA635071). My local dealers wanted $8 and $12 bucks, respectively, for something that lists for $1.39!

 

Say, how do you guys break loose the bolts on the crank pulley and cam sprockets? I don't have that Subaru special tool so I cut the old accessory drive belt and timing belt and wrapped them around the pulley and LH cam sprocket respectively, then used a huge chain wrench from Harbor Freight to hold the pulley/sprocket while using a socket and breaker bar. It worked fine on the crank pulley, but I think I might have deformed the LH cam sprocket from the force of the chain wrench.

If you have a manual, you can put it into 5th gear and have somesome stomp on the brake while the old belt is still one there. Your method also works.

 

As for the coolant, I've used Havoline Dexcool with no problems -- any other long life coolant works the same way but without the liscensing to push up prices. Zerex is great.

 

Hieu

[Wayne Boncyk]

I've freed up my crank bolt by using an impact socket on the end of a breaker bar long enough to reach to the ground, then with everything wedged well in place, bumping the starter until the bolt loosens. Not a method for the faint of heart, but it works. Tightening, with my auto tranny, involves pulling the rubber cover off a port that allows you to see the flexplate. You can then wedge a large screwdriver in there to capture a notch on the flexplate as you tighten the crank bolt down.

[blitz]

The Permatex grey works great ...I used it to seal the oil pump during my last T-belt change. I also used it to re-install my 4-EAT pan. Just be sure to clean and dry the surface before applying. In a pinch I think the Permatex black would be as good.

 

**** ******!