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Oil leaking FROM exhaust manifold LH - bent valves?
Recently I tried to fix an oil leak from my camshaft caps or cam seals on the LH cylinder head. So I removed the timing belt, cam gears, valve cover and so on. A drop used to run along the valve cover and down to the subframe and anti roll bar.
While I seem to have fixed that problem it seems I may have caused something far worse. Oil seems to push out from the exhaust ports, through the gaskets and onto the exhaust manifold flange. As far as I can tell it's not coming from the valve cover, I've tried resealing it and I used new original gaskets. Sealant according to the FSM and even some extra. But the seam between the valve cover and the cylinder head is dry, no evidence at all of any leak there, and it's not running from the timing cover along the cylinder head either.
I have probably had the engine ran for two hours about now. All the other fluids that leaked into the exhaust manifold have pretty much burnt away but I can see new oil coming from the LH exhaust manifold for every time it's started. It smokes pretty badly as well.
I never had a leak at all here before I took everything apart which makes me wonder if I possibly bent the valves or something on disassembly. Not against the pistons of course but against each other. When releasing the belt the upper cam spun but that's not usual as I understand. I tried avoiding that but I didn't take much for the cams to rotate.
The cams have not been rotated with force against each other but I don't know if the force from the valve springs is enough to bend the valves.
Compression seems OK on both cylinders, it doesn't smoke noticeably. Not any noisier on that head than before. Spark plugs don't seem to be fouled with oil. A slight misfire between 1500-2000 rpm but it could be mapping or another issue with this engine (#1 running rich, others are lean. Slightly lower compression on that cyl).
I'm really confused about this. It doesn't seem to be an external leak from the valve covers or cam seals etc as the head itself is dry until the oil is starting to come out from the exhaust manifold gaskets. Also this oil/fluid doesn't exactly smell or look like my engine oil does. It's more golden brown and with a different kind of smell so I'm thinking it's got to be some kind of a mix from the exhaust ports.
How easy is it to bend the valves? I can't think of anything else that could have gone wrong.
I could try resealing the valve cover a third time but im 90% sure it's not causing the leak. The oil really looks like it's coming from the other direction. There isn't a single drop on the rear of the valve covers.
I'm prepared to remove this engine anyways. I don't think the piston rings on #1 are perfect. I only got 360 hp (310 hp at the hubs) from a MD321T+ at 1.5 bar on this engine on 98 octane.
Thankful for any advice. Doesn't help being in Sweden were we have very few Subaru experts. I know this will look like a typical valve cover leak but I would expect the head and valve cover to be soaked with oil just nearby the gasket in that case.
Last edited by Turbovin; 10 January 2020 at 04:32 PM.
Are you sure its not oil which has leaked out when you had the cam cover off and its trapped in the heat shield burning off ?
Easy enough to drop the exhaust knuckle off on that side and look up into the exhaust ports to see there is oil being burnt in the cylinder.
Are you sure its not oil which has leaked out when you had the cam cover off and its trapped in the heat shield burning off ?
Easy enough to drop the exhaust knuckle off on that side and look up into the exhaust ports to see there is oil being burnt in the cylinder.
It's a twin scroll manifold so one piece but I've removed it 5 times and I have tried my best to clean it with brake cleaner and my air compressor. It's dry in the center and around the RH head. They smoked a lot in the beginning also.
The pipes inside the upper heat shield on the left side look dry further down but I guess it's possible that there could be some oil trapped in the insulation. But everytime I removed the exhaust manifold I made sure to get the exhaust flange as clean and dry as possible. Is it even possible for the oil from the heat shield to flow up to the flange, gravity should make that difficult?
The exhaust ports are all a bit oily and sticky at least closer to the valves (not all the way down to the exits), except cyl 1 which is very sooty. But no problems with a leak on that cylinder head. I'm not sure if a healthy Subaru engine should be completely dry in the exhaust ports? My old (failed) original engine is oilier than this but that never had a leak like this.
It would be great if it still was oil trapped inside the heat shield but it doesn't seem logical to me, especially as the other side is fine now. It really appears to be new oil coming each time I run the car. The flange gets totally soaked and when it's been running long enough it spreads down/up to the cylinder head itself.
Looking at the gasket it has a litte bit of oil on it on removal. If it was trapped inside the heat shield it feels a bit unlikely for it to get in between the head and the flange?
Last edited by Turbovin; 10 January 2020 at 09:28 PM.
At the end of the day if the gasket is new and secure in theory the gasket should seal and not let any fluids out of the manifold. Wash all down with degreaser and let dry then inspect again also you'd also be surprised how much oil the insulation can hold on the headers/manifold.
Also as its the left hand head have you spilt any oil while filling up.
Last edited by 1509joe; 10 January 2020 at 09:45 PM.
At the end of the day if the gasket is new and secure in theory the gasket should seal and not let any fluids out of the manifold. Wash all down with degreaser and let dry then inspect again also you'd also be surprised how much oil the insulation can hold on the headers/manifold.
Also as its the left hand head have you spilt any oil while filling up.
The flange is a bit rusty on this manifold so maybe it doesn't seal up as well. I think I replaced the gaskets early last year and I have only driven the car 2000 km's with this engine so basically new. But of course they get a bit crushed when fitting and removing the manifold.
I did not spill any oil. And as I said this oil or fluid isn't even the same colour or smell as my engine oil (Fuch Titan Race Pro S 10w-50). Maybe it turns to this once burned by the exhaust flange but it does not have the typical smell of engine oil. If it really was a leak from the valve cover or cam seals it should be identical to what's in my oil pan. It's hard to explain but it feels and smells like it's oil mixed with condensation from the exhaust or something,
I will try to run it for some more before removing anything but things haven't really improved at all.
Last edited by Turbovin; 10 January 2020 at 10:10 PM.
Unusual for the face of the manifold to get that rusty so that it will not seal unless its been lying outside or similar. Don't think at this stage with what you have checked that this is your problem. Give it a good run.
There also on your picture seems to be a damp area at the front of your head and the manifold appears to be a little more moist at the front than the rear so maybe you have a leak up above that is blowing round the corner when on the move.
Last edited by 1509joe; 10 January 2020 at 10:15 PM.
The only other thing is see those water pipes they can be a proper pain to seal with a bit of age. Are you sure its not burnt antifreeze you are seeing. Pressure test the system and check for leaks.
The leak from the manifold came for the first time after I put everything together, camshaft caps, cam seals, cam gears and timing belt. The manifold wasn't removed during this so it's leaking from somewhere where it didn't before anyway.
The car is in storage for the winter so I can't do a proper run yet with all the road salt outside. I do have an extra twin scroll manifold but that is somewhat bent and not fitting properly but maybe I can try to fit it and see if this issue remains. That one is absolutely dry at least.
All hoses are new on this engine. Many of the pipes are new as well. It's not been losing any coolant but I'll check it out to be sure.
Thanks for the ideas.
Last edited by Turbovin; 10 January 2020 at 10:22 PM.
I had a massive oil leak about 15 months ago now (oil cooler hose came off), which soaked the radiator, sump and radiator brackets/cross member.
I didn't run the car for close to a year after this, and cleaned the underside several times to "dry metal" (even took the rad out for better access).
It STILL ends up with an oil film on it after a couple of weeks if left, even though there is definitely no new leaks.
A bit of a random story, but my point is that oil takes a long time to come out fully in my experience. Having said that, your problem might of course be completely different
Yes I understand that, and Subarus seem to be a bit special when it comes to oil leaks. I should have left the minor leak it had before that only gave a small drip on the anti roll bar. At least that never smoked
The leak from the manifold came for the first time after I put everything together, camshaft caps, cam seals, cam gears and timing belt. The manifold wasn't removed during this so it's leaking from somewhere where it didn't before anyway.
The car is in storage for the winter so I can't do a proper run yet with all the road salt outside. I do have an extra twin scroll manifold but that is somewhat bent and not fitting properly but maybe I can try to fit it and see if this issue remains. That one is absolutely dry at least.
All hoses are new on this engine. Many of the pipes are new as well. It's not been losing any coolant but I'll check it out to be sure.
Thanks for the ideas.
Even the fans kicking in would blow coolant off those hoses I always try and fit Samco hoses on those two particular hoses their a nuisance.
Not sure about the twin scroll setup but I recently stripped the centre manifold pipe on my STI hatch. That's the pipe between the two cast manifolds. It's surprising what's behind the heat shield. There's lots of places for oil to hide and 2 pieces of insulation that will hold it for ages.
It obviously looks a bit different with the twin scroll dual pipes but the same principle. I actually had the heat shields off as I took the heat shields from my other manifold to the one I have on my car. Less rust on the heat shields on the other manifold but that didn't fit good against the up pipe, bent somehow.
The problem is that it doesn't really smoke from the manifold or the heat shields, just from the flange that gets soaking wet after a while. I have cleaned the flange with brake cleaner and it's pretty much dry now. But I haven't started the car yet due to bad weather.
I'm a bit pessimistic as I have got the flange dry the other 10-15 times too but when the car's up to temp and especially with some revs on the engine the flange is soaked with this oil/fluid again.
But I'll start it again when I have the chance, I just know what the result will be already.
The oil trapped inside the manifold I know very well about as it got in on the RH head and also some power steering fluid in the centre by mistake. It took a long while for that to dry and stop smoking. But somehow a new leak on the LH exhaust flange for every time it's started, not immediately but once warmed up.
I'll drive to a nearby workshop to get another opinion when I have a chance.
If it was oil trapped in the manifold I would expect less smoke for each time the engine has been running. But more and more smoke the longer the engine is run.
Last edited by Turbovin; 12 January 2020 at 09:36 PM.
First pic is before it was started, sprayed it down with some brake cleaner the other day.
Then I ran the engine for 15-20 mins
It seems to be even worse on the other side of the flange.
I removed one off the valve cover bolts to let some engine oil out to show that the oil or whatever it is is different in colour and smell from my engine oil.
The fluid from the exhaust manifold on the left paper, engine oil on the right
I really think I've managed to mess up something mechanical on the LH head, valves, guides or seals. It does misfire quite a bit between 1500-2000 rpm and the fueling is off there too, running lean. It did have a slight misfire before too but not this bad. Also I think it smokes a bit too much, thick grey though not exactly blue.
I was prepared to remove the engine before I started this thread and still am. As I wrote the compression is slightly down on #1 and the spark plug, exhaust valves and runner in the manifold are very black and sooty.
What do you think about this knocking/tapping sound? Is it from the forged pistons or does it sound more like valve clearances being off? Coolant in operating temp here but not the oil. It does quiet down a bit but not fully when fully warm. Oil pressure is fine.
If you zoom in on your second picture it appears to be damper down below the flange as if its travelling up from the insulation in the heat shields.
You wouldn't have a water leak on the head gasket behind/above the manifold running down into the insulation as you say it seems worse on the inside.
I had both valve covers off and I think it should be seeing similar problems on the other head in that case. Looking further down at the joint to the next section of heat shielding you can see traces that it indeed has been oily there. But I think the pipe itself looks dry now and can't really say that the insulation looks wet either. I would think it would be absolutely soaking for it to be able to travel up like that. I could drill out the rivets for the upper shield to remove it and have a look.
And by now the engine must have been running for 2,5 hours at least. Mostly idling but some easy driving as well. The head gasket crossed my mind but that was fine before and makes no sence that I would go bad from removing the parts that I did.
Not really used to tasting fluids around the engine but from the smell or consistency it's not either coolant/antifreeze or pure engine oil. Not like power steering fluid either. It's really hard to describe, it could be a mix of things. This is exactly why it's so hard to identify and I can't say that I ever felt anything similar to this. If it smelled like engine oil it would be easier to find. I had some power steering fluid mixed with engine oil on the other side of the manifold but that was different to this. That also dripped down to the ground in the middle of the manifold.
I'll drop the manifold some day to have another look.
Last edited by Turbovin; 13 January 2020 at 12:16 AM.
I do have my other twin scroll manifold but that leaves a gap of at least 1 cm at the up pipe flange for some reason. But maybe I can force it together for just a test, that would tell quickly if it's still trapped oil or something else.
This is certainly odd.
you say the exhaust flanges are getting wet with something. It's stating the obvious but the only way something can get there is through a failed manifold gasket or from an external source.
If it's external, it's either running onto the flange along the cylinder head or being sprayed on from somewhere like a coolant hose. They can develop pinhole leaks that spray an invisible jet onto an adjacent area. That only happens when the engine's hot and coolant is pressurised. The rag on the left looks like rusty water. The other possibility it steering fluid. I can't remember if the rack is suitably placed to spray the manifold. Hold a piece of card by the manifold. Any jet will soon show. The only other pressure source is oil from an AVCS valve. Do you have AVCS?
You can check for fluid running over the cylinder head with a rag on a screwdriver.
Fluid should not make it across the manifold gasket. Both head and manifold faces should be clean and flat. Manifold gaskets are very intolerant of surface defects. You say No1 exhaust is black. That could be a failed valve stem seal. Oil could then leak into the exhaust, partially burning before it leaks out. That would explain the discoloration but the smoke would be blacker than you describe.
Good luck
and first photo(first message ) is before the seal change all right? i guess you have same leak before ?
Do you mean a leak down test? No I haven't.
The first picture is after the change of seals. Just with a different sealant for the covers, I resealed them later with no change. Before changing the cam seals etc it was 100% dry around the exhaust manifold gaskets.
This is certainly odd.
you say the exhaust flanges are getting wet with something. It's stating the obvious but the only way something can get there is through a failed manifold gasket or from an external source.
If it's external, it's either running onto the flange along the cylinder head or being sprayed on from somewhere like a coolant hose. They can develop pinhole leaks that spray an invisible jet onto an adjacent area. That only happens when the engine's hot and coolant is pressurised. The rag on the left looks like rusty water. The other possibility it steering fluid. I can't remember if the rack is suitably placed to spray the manifold. Hold a piece of card by the manifold. Any jet will soon show. The only other pressure source is oil from an AVCS valve. Do you have AVCS?
You can check for fluid running over the cylinder head with a rag on a screwdriver.
Fluid should not make it across the manifold gasket. Both head and manifold faces should be clean and flat. Manifold gaskets are very intolerant of surface defects. You say No1 exhaust is black. That could be a failed valve stem seal. Oil could then leak into the exhaust, partially burning before it leaks out. That would explain the discoloration but the smoke would be blacker than you describe.
Good luck
As far as I can tell the outer edges of the cylinder head are perfectly dry so it's not running from timing belt cover, and it's not developing from the valve cover gaskets. Perhaps if it's coming from the cylinder head gasket. I do have AVCS heads. I first thought of the oil line between the front of the head and the solenoid but I used new copper gaskets and it's dry under the banjo. Will look into it some more this weekend.
Ok so I went to my garage after finishing the evening shift at work. I began with removing the exhaust manifold and drilling out the spot welds or whatever they're called, holding the upper heat shield in place. There really isn't much insulation in the upper heat shield and the pipes after the bend were pretty much dry. Very wet just below the flange though.
So I decided to try and fit my other twin scroll exhaust manifold, the one that fits like crap. I had to use my jack and some longer bolts and force it together with the up pipe.
At first I saw some water/condensation bubbling on the LH head but once warmed up it sealed up. Ran it long enough for the fans to come on and not a single leak or any smoke at all
It must have been the steering fluid mixed with engine oil that smokes up from the center of the manifold but I really made no sense to me as it stopped smoking on the right side a long time ago. I should have believed the easy solution but it really looked like there was new oil coming from somewhere.
This exhaust manifold is in much better condition but needs rewelding for it to fit properly against the up pipe. It leaks pretty badly from the up pipe flange so not a good idea to force it together like that, it was just for a test.
Last edited by Turbovin; 14 January 2020 at 03:02 AM.
Yes I know about the legacy set up and what's different but this one is identical to the other one I have, I think the car it came from must have been in some kind of accident for it to happen.
At least there´s some hope for the old Type R now
And thanks again everybody for helping me solve this.
Last edited by Turbovin; 14 January 2020 at 01:43 PM.
10 January 2020, 04:14 PM
Oil leaking FROM exhaust manifold LH - bent valves?
Check about legacy twin scroll set up there is slight differences 
