Yet another oil leak problem

[geoduck]

Hi All,

I have a 2004 XC70 with 177k miles and a newly developed oil leak on the passenger side of the engine. I've searched through this forum and read every thread with 'oil leak' associated but I couldn't find answers to some of the questions I have. I took the timing cover off (the top and the front cover) but there was very little oil in that area and the timing belt did not have any oil on it. There were a couple of drops of oil near the bottom of the crank pulley but these did not get worse when the motor was running. The oil appears to be coming from the back side of the timing belt housing (part #4 in the diagram) and dripping onto both the CV joint and part #20 in the diagram. It seems like the leak is coming from near the front exhaust cam seal but I can't see it directly since there is very little oil in the timing belt housing.

5076

I have not cleaned the PCV system yet on this car and there is a small amount of smoke coming out of the dipstick tube when the dipstick is removed. I've tried driving the car with the dipstick 'loose' in the tube and with the filler cap loose but the leak seems to remain the same. If the PCV system is clogged and causing the oil leak should these steps reduce the leak? I won't have time until next weekend to address the PCV system but I'm also worried that damage to a seal has been done and I'll now have to replace the front exhaust cam seal, which I feel is a little beyond my skills. It currently leaks about 1 qt every week (~500 miles) but I can't tell if it's getting worse (I'm now keeping track so I know.) If it is a cam seal, approximately how much time/miles do I have until it completely fails? Is there anything else in that general vicinity (around or below the front exhaust cam seal) that could be causing this leak? The leak also seems to vary in severity even while the engine is just idling - one time I looked under the car and could see drips about every 5 seconds but when I went to quantify it so I could see any effect loosening the dipstick had on it, it slowed to 1 drip every 3 minutes with or without the dipstick being loose.

I'd appreciate any ideas or advice anyone has on this situation.

Thanks,
Kelly

[JRL]

Front cam seals

[vtl]

Seal or worn CVVT hub.

Also #20 covers half-axle bearing, check that bearing is not in oil, otherwise it will quickly dry out. The bearing itself it not very expensive (~$15 for good 6002-RS), but you need to take axle out and use a press.

[DakotaMike]

I'm with JRL, cam seals. Removing the dip stick released the pressure and thus the rate of oil being pushed out of the engine. Judging by the mileage you are coming up on a timing belt anyway change and the seals are right there. Don't change the seals before the PCV is fixed or the leak will quickly come back or the oil will find another way out that could be more expensive.

[Astro14]

At 177k miles, it's a good bet that your PCV is plugged. Your test seems to confirm that.

I would fix that first, since you can, and see how bad the leak is with a functioning PCV.

PCV Pressure caused the leak to begin with, if you don't remove the cause, you'll be chasing leaks all over the engine.

With luck, fixing the PCV may slow the leak and allow you to defer the cam seals.

When you do the cam seals, make certain you do the timing belt and tensioner at the same time. Frankly, if the water pump is original, do that when the TB comes out.

[geoduck]

Thanks for the help and advice. I want to relate another experience I had today with this oil leak and ask a few questions. There was a fail amount of oil on the fresh piece of cardboard under the car this morning so I took the car out to warm it up and then topped the oil off to the top mark on the dipstick. I took it on a long drive, mainly on the freeway (70+ mph) and on highways (60 mph) to see how bad the oil leak was under those conditions (I kept the filler cap and dipstick loose.) I drove 180 miles to a ski area with one stop along the way and when I arrived there was no noticeable loss of oil - it was still right up to the top mark. I let the car sit while skiing for several hours and when I got back to it there was no oil on the ground under the car (same as when I had a short 10 min stop along the way.) I then drove 10 minutes down the highway and stopped to eat dinner, leaving the car for about 1 hour. When I got back out to the car, there was a large spot of oil underneath it. I drove back home, parked the car for a few minutes, and then checked the oil and it appeared to be about 1 x mark (on the dipstick) down. I also noticed a fairly rapid dripping right when I parked it. So I have a few questions about this and the advice that has already been given.

1. Is there a logical explanation for the car's behavior on the trip today?

2. Is it okay to drive the car for a week or two with the oil filler cap and dipstick 'loose'? There is a baffle under the filler cap so oil doesn't significantly leak out even when the cap is loose. I know there are emission concerns but can it damage the engine in some unforeseen way?

3. In doing the PCV system I've seen some postings where people don't replace the really expensive hose assembly but simply clean it out and/or refurbish it. Money is a bit tight right now so if this is an option I'd like to try it - any advice?

4. The timing belt was replaced at 120k (the recommended mileage for 2004 XC70s) so we still have 60k to go before a new one. If I do the cam seals myself I'd like to keep the timing belt to save money (it's not covered in oil) so can I simply mark the belt and the cam and crank sprockets so getting the timing right when it goes back together is easier?

5. Is there a good write-up on changing the front cam seals on P2 cars? I've seen some about the rear seals but not the fronts.

Bonus. Any guesses as to how much longer before the seal completely goes? As I mentioned, money is tight so I'd rather do the work myself but I'm not sure when I'll have the time. I have a '98 V70 with 268K that is needing my attention as well because of a leaking flex pipe on the exhaust manifold.

Double Bonus (and don't kill me for asking.) Is there any stop-leak type product that can at least slow the leak (and not irreparably harm the motor) until I have a chance to fix it?

Thanks again,
Kelly

[Xheart]

Repair one first with OE parts. I did not know REAR CAM seal was leaking on mine for three years.
This was a sign of clogged PCV on my 97-850. Try this method on yours to isolate, warm up the engine.
5078

[Astro14]

I would never use any kind of oil additive in this car...too many things to go wrong and too costly...stop leak is generally garbage, and every manufacturer specifically says not to use it.

That said, a quality high-mileage oil, like Mobil 1 HM, might slow a leak, once the PCV pressure is removed from the seal itself.

[geoduck]

Thanks for the advice about oil additives -- it's pretty much what I thought but I just wanted to double check.

I did the glove test and sure enough it inflated so I'm going to do the PCV system tomorrow. I did it last year on my NA '98 V70 so hopefully it's not that different.

Anyone have ideas as to why the leak seemingly stopped on the long freeway trip?

Thanks,
Kelly

[DakotaMike]

I would have expected more pressure = more oil(?) Anyway we know the PCV is blocked and it should be the first step. I had a buddy that was out of work that had to wait to pay for the PCV parts on his 850 and he put one of these over the dipstick hole for a few months, obviously the dip stick was removed first. Sometimes if you're broke you have to try and not blow seals your engine somehow.

5080

[Xheart]

It is an illusion that the leak stopped. Once accumulated it becomes visible in strange places.
One quart every 500 miles is a lot.
I had a severe clog. The damage was done to the seal before I discovered the PCV problem.
PCV clean up your first step in finding a cure.
A dear friend often reminds me "winners don't quit, quitters don't win".

[sjonnie]

Anyone have ideas as to why the leak seemingly stopped on the long freeway trip?
Sure, in order of what I'd regard as most probable explanations:

1. High speed causes the oil to be blown out from the engine splash shield so nothing accumulates
2. A certain amount of oil must accumulate on the splash shield before you notice anything dripping
3. Oil only leaks from the bottom of the camshaft seal after running the engine and when the engine is switched off.

[geoduck]

Thank you for your ideas on the strange behavior during the trip. A couple things to note -- I removed the splash shield to help trace the leak and left it off so there's no accumulation on it, and it's not just that I didn't see any oil underneath the car but the actual oil level didn't go down a bit and I would have expected, based on how much it's leaking, a noticeable decline on a trip of 180 miles.