Oil leak C5 v6

[zeeshanzaki]

I replaced gasket of the rocker cover to stop slow oil leak but it made it worse. I can't see much oil leak from the rocker cover but there is oil around lower part of timing cover. The leak was not bad before replacing gasket. Where could be the oil leaking from? Could it be cam seal oil pump improper application of gasket sealant?

[xantia_v6]

Which engine does your car have? There were 2 petrol V6s and 2 Diesel V6s fitted to the C5.

[zeeshanzaki]

V6 petrol

[zeeshanzaki]

I also noticed that leak increased since i used 15w50 fully synthetic oil in last service.

First time when I did rocker cover it was still leaking so i thought it may not have sealed properly. so i did again. Drew the car 2-3 days short distance (10km) with no leak. but when I drive longer distance it started leaking again. Checked the back of the engine and can't see any oil below rocket cover. so this time it is leaking from somewhere else.

[GiveMeABreak]

That's definitely the wrong grade of oil. You have the ES9J4S engine (3.0l V6 24v 210). There are 3 recommended grades of engine oil for this engine - depending on the climate of the country you are in: The 15W50 oil you are using is too thick.

I would certainly drain it out and choose the correct grade for your climate out of the options in the table below. Although having the thicker engine oil won't immediately cause damage, when the engine is cold, it might be harder to pump around the extremities. This can lead to damage in the long run if those parts don't get coated because the pump is having difficulty pumping the thick oil around. Most of the engine wear occurs at startup when the engine is cold. So although probably not the cause, it won't help.

Engine Type	Engine Id	5W40	10W40	0W30	5W30
ES9J4	XFX	OK	OK	NO	OK
Temp	Range →	-30°C to +50°C	-20°C to +50°C	X	-30°C to +45°C

[zeeshanzaki]

I can change the oil to 10w40 if that can help or its too late now.

I checked the rear of the engine and here is the location of oil leak. If it is cam seal then the timing belt would already started sleeping, but it is running fine.

[xantia_v6]

I don't think that the oil is likely to have caused any damage yet. I think that the leak is most likely from the end of the cam cover, up against the timing belt cover. If the leak was inside the timing belt cover, I think that oil would only be coming out the bottom.

I think that it is not too difficult to remove to top rear timing cover (a lot easier than the other 2), to inspect the amount of oil in there and the state of the belt (the screws have 7mm heads).

[zeeshanzaki]

To remove rear timing cover, i have to remove engine mount, fuel lines and coolant tank to access one bolt behind the mount. Is there any other way to remove rear cover?

[zeeshanzaki]

i remove few bolts from both covers just to see if there is any oil on timing belt. But it is clean.
Could it be high oil pressure causing cam seal to leak as there is no way to release pressure from leaking rocker cover.

[xantia_v6]

i remove few bolts from both covers just to see if there is any oil on timing belt. But it is clean.
Could it be high oil pressure causing cam seal to leak as there is no way to release pressure from leaking rocker cover.

The seal on the camshaft is not subject to high pressure oil, only the pressure of the fumes in the crankcase. I have never heard of one leaking.
It is more likely that the cam cover is not sealed properly, particularly on the lower edge where there is a pool of oil on the inside.
Another possibility is that the aluminium block that the cam sits on is not sealed properly to the head, but any leakage there is normally minor, and you need to remove the cams to fix it anyway.

[zeeshanzaki]

I redo the 4th metal cover so it should not be leaking from the side. Only suspect is the plastic cover might be leaking from the timing cover side. I found that the platic cover has gasket around two holes as shown in the photo (not of my car). Could this hole lead behind timing cover and if it is leaking from there then oil can pass behind the cover.

[xantia_v6]

Those 'holes' are recesses for the bolts holding the camshaft bearing cap, so they do not lead directly anywhere.

It sometimes happens that the whole aluminium piece that sits over the camshaft is not properly sealed to the cylinder head, and leaking there, but I have only seen that once and the leak was slight.

[zeeshanzaki]

Is there a way to fasten cam cover bolts without removing them to reduce leak. If so, will that affect timing belt.
Or using Stop Leak will reduce any oil leak.

[zeeshanzaki]

I checked the photos that i took last weekend and it shows leak from rear rocker cover. Strange as i did this cover twice and still leaking.

[zeeshanzaki]

Found the source of leak but not sure if its coming from rocker cover or cam seal which behind timing cover bracket. Leak incrased only after doing rocker cover seal.