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S40 / V40 '96-'04 General Forum for the Volvo S40 and V40 (Classic) Series from 1995-2004. |
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Bad oil leak ?Views : 1276 Replies : 10Users Viewing This Thread : |
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Nov 18th, 2018, 23:30 | #1 |
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Bad oil leak ?
Car is a 01 V40 130 000 miles, petrol, auto gearbox, there is oil seeping from the cylinder head, oil makes its way to the accessory belt area (one pulley has a bit of oil on it). The rear of the timing belt plastic cover also has oil on it. My guess is it comes from the head (gasket ?) or the sparkplugs, but I am no mechanic and didn't have torx wrenches on hand to remove the plastic covering the spark plugs.
How bad is this if I wanted to fix it ? There is no other sign of head gasket failure. I didn't notice much oil under the car. Last edited by V40addict; Nov 18th, 2018 at 23:34. |
Nov 19th, 2018, 00:07 | #2 |
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Last Online: Oct 13th, 2023 06:46
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Might be the oil seal. Each camshaft has an oil seal at either end. I'll keep it simple.
The top of the engine, through which the spark plugs go, is the "rocker cover". It's called this because underneath it are traditionally "cam followers", which rock, each actuating a "push rod", which forces open a "valve" in the cylinder. The days of cam follwers are gone, replaced by newer technology ("hydraulic lifters") but the rocker cover name has remained. If you look closely at your engine, you'll notice there is a very fine seam between the rocker cover and the cylinder head, with black circular plastic oil seals halfway between the two. Behind the seals are the ends of the camshafts, which sit in high pressure oil, so the seals are important because the camshafts don't use any bearings, they literally just rest between the rocker cover and the cylinder head with high pressure oil squished between. They all leak eventually. I would change the oil seal before before blaming the head gasket for the simple reason that you can change these without splitting major engine components apart. Especially since you are not noticing any other symptom for head gasket failure. Changing a head gasket is very invasive and rather complicated. Changing an oil seal is much simpler. Basically the procedure is this: Remove aux belt, remove timing belt, remove the pulley, pluck out the oil seal, knock the new one in, then put it all back together again. So that's where I'd start if it was me. |
Nov 19th, 2018, 00:39 | #3 |
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Thank you. It would make sense, if these seals are gone, oil under pressure is sprayed all over I suppose, therefore even the top of the timing belt cover is soaked in oil.
The procedure you describe involves a lot of work though, like changing the belts, and the timing belt has been changed 2 years ago so not coming due. If the car isn't driven much , can you get away with not doing the repair ? Or is the oil really bad for the belts ? |
Nov 19th, 2018, 01:25 | #4 |
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Difficult to be sure. You'd need to ascertain exactly where it's coming from to be certain.
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Nov 19th, 2018, 03:10 | #5 |
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I read it could also come from a VVT pulley seal, would make sense since there is oil on its cover but on the other hand there is even more oil seeping from around the thermostat and down the accessory belt (exactly like I had coolant leaking on another car) so I don't think this would be the VVT pulley seal.
Either way, it looks like a costly repair. I read the belts can slip because of the oil. Does it do the same damage as a belt failure ? I will try to look closer this week. |
Nov 19th, 2018, 09:48 | #6 |
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Yes, that's exactly the seal I was describing. I said camshafts, but that's because the VVT pulley is attached to the camshaft, and where the shaft goes through the side (actually the front, but let's not be pedantic here, transverse engines like these are mounted sideways in the car just to confuse things) of the engine there is a seal.
I'm intrigued by the oil appearing on the thermostat housing though. Directly above that, on the very top, there is the VVT solenoid which controls oil flow to the VVT itself. So that's a potential source and much easier than messing around with belts. Or even the rocker cover itself. It has a liquid gasket rather than a traditional cardboard one. Has the engine ever overheated? |
Nov 19th, 2018, 13:32 | #7 |
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I do not know the history of the car, but given previous owners, overheating is not the first thing I would suspect. I think the engine has negative crankcase pressure : I checked PCV, it sucks air when you remove the oil filler cap (and btw I don't think the cap is faulty and the cause of the leak since the oil is under the plastic cover).
I had another car which leaked coolant at the thermostat, it took me a while to trace the leak to the thermostat and it was the seal inside the thermostat . The coolant would drip ïn a crevice formed by various engine parts next to the thermostat and then on the passenger side where the accessory belt is. The oil at issue here appears to be taking the same path, so yes it could be coming out of the VVT solenoid which is next to the thermostat but last time I looked at it I could not see any oil on the top side of the parts. Last edited by V40addict; Nov 19th, 2018 at 13:58. |
Nov 20th, 2018, 21:42 | #8 |
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Could be the VVT itself that's leaking and/or the camshaft seal in behind the gear. The VVT sometimes leaks from the little metal plug visible from the front. When it does the belt tends to get pretty wet.
When a cam seal leaks it can leak slightly (belt and gears will be dry but engine block will be caked over time) or it can leak drastically (like mine on my V70 is right now). When it leaks drastically, you will have oil all over the place and oil consumption will be extreme (I used 1 quart per 6km)! Take a good hard look at the front of the VVT to see if the plug/pin is leaking. If it's not, I might be tempted not to replace. The challenge is that you need to take it off to replace the seals so if someone else is doing the work for you, do it all in one shot.
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2003 V40 1.9T B4204T4, 197,000miles (sold but alive!), 2004 S60 2.5T, 160,000miles, 2010 V70 3.2, 125,000miles, 2002 V70XC 2.4, 175,000miles Click here for my x40 and V70 P3 repair guides |
Nov 22nd, 2018, 15:23 | #9 |
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I took the covers off to get a better look. Both pulleys (exhaust and intake is that what you call them?) have oil on them, belt contaminated (and that's why there was oil through the top of the cover).
It's more oily on the front pulley which would explain why it seeps above the thermostat. There is oil including small puddles on the rocker cover, but not a huge amount and oil doesn't appear to be flowing from that area to the thermostat area. It seems it comes from one of the pulley' seal (front pulley I would say), sprays in a circular motion (on the back pulley and to the front). But I didn't look with the engine running. Now the bottom of the engine case has oil on it because of all this, and this is an issue with MOT apparently. My question would be this : given that the car is not going to be used and parked in a garage (my intention anyway), if the oil on the belt is to a certain extent wiped off with a rag, and it dries over the coming months (it's actually pretty much dried as it is with the friction I think) while perhaps I look for a temporary fix for the seal (there are sealant compounds that you mix with oil) , can I buy myself time when I restart the car in say a year or two ? I do not know when the current car in use will fail and be scrapped, so it could be years before the leaky car will be used and I will then have the belts changed sooner or later after restart depending on the evolution. Last edited by V40addict; Nov 22nd, 2018 at 15:30. |
Nov 24th, 2018, 13:16 | #10 |
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Depends how severe the oil leak is. Only one way to find out. Clean up the mess on the engine and start her up. Drive it around the block and see if the engine underside is wet again. For pete’s Sake please don’t use any sealant compound on this engine. I’m convinced that this brings on nothing but future grief. If you are going to need to drive it, fix it proper. It’s not that bad a job, basically just a timing belt job with a twist it two.
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2003 V40 1.9T B4204T4, 197,000miles (sold but alive!), 2004 S60 2.5T, 160,000miles, 2010 V70 3.2, 125,000miles, 2002 V70XC 2.4, 175,000miles Click here for my x40 and V70 P3 repair guides |
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