Oil on top of pistons

[Ivan_B]

This is for my other car, hens posting in the off-topic section.

I was getting an intermittent single-cylinder misfire code, on idle only. Swapped the coils, plugs, injectors - no change. Tested compression - 1 & 2 are a bit low (in comparison to 3 & 4, but well within specs. Finally took a bore scope to it, and here is what I found.

1 has the most oil, 2 is a  bit less; 3 and 4 are normal, no oil.

 

I am thinking - leaking valve stem seals? This is a 90k engine. I've noticed no oil/coolant consumption, and no smoking of any kind, yet 🙄

 

[plymouthcranbrook]

This is one of several articles I found on oil consumption.  I kind of remember it being blue smoke on acceleration is rings and a puff on deceleration being valve guides. How did the plugs look?  I have never seen that much oil on a piston top that wasn’t burned. I don’t see how you aren’t getting a drop on the stick.

 

https://www.theenginebuilders.com/new-blog/2020/1/24/diagnosing-oil-consumption-issues

Edited January 20 by plymouthcranbrook

[JBNeal]

If those marks on the piston tops were made by contacting the valves, engine failure is imminent...saw this on an Ecotec that snapped a timing chain link 💥

[Ivan_B]

@plymouthcranbrook I am also surprised that I am not noticing smoke, etc. Maybe it is happening during deceleration, not sure. I don't really have anyone to check, at this time. The exhaust does smell distinctly, but it was always this way as long as I had the car 🤔

The plugs had plenty of carbon, I cleaned them, and they look better, but the 1st one is very wet with oil.

 

@JBNeal Are you referring to the 4 groves? These are the cut-outs for the valves If the pistons hit the valves, I would have bent valves and no compression.

 

Also, I do take back the statement about not noticing the oil consumption. It looks like I did not notice any "in the past". Just checked, I am 1/2 qt. low. So I guess, it is going right into the cylinders 🫠

Edited January 20 by Ivan_B

[Los_Control]

I was thinking the same about the top of the pistons .... looks like divots.

I think it is a optical illusion of the burnt, dried up oil on top of the pistons. .... The puddle of oil is not yet burned.

 

I'm just guessing, but agree with Ivan on valve stem seals .... could the oil in the head leak down past the seals with engine not running.

Then you would have a puddle and the puddle would be burnt on start up. .... leakage would be burnt while running .... puddle would occur while not running.

 

Makes sense to me, no way for it to get past the rings if not running.

[Ivan_B]

1 hour ago, Los_Control said:

Then you would have a puddle and the puddle would be burnt on start up.

I did not even think about this, that way, thank you for bringing this to my attention. Indeed, there is a liquid puddle of oil in 1 & 2. I suspect that the amount that can seep through the rings would've been burned-off. While, if the rings were leaking that much it would idle like a tractor (which it does not). I'll try to take the intake manifold off, later today, to check what the intake stems look like.

[Los_Control]

Might help other people that are actual mechanics ..... I am not and have proven it many times over 

What year and engine are you working on? Some engines have known issues like leaking intake gaskets or many other possibilities.

 

But yeah, seems like the oil is coming from somewhere in the top end.

[Sniper]

Might help if we knew what engine we were looking at?

 

Some engines have certain idiosyncrasies, such as the SBC and it's OEM valve stem seals failing early.

 

It could be any number of things, like an intake leak allowing the engine to suck oil into the cylinder, assuming that;s applicable here.

[Ivan_B]

This is the Chrysler 1.4 multiair, non-turbo (2012 Dart, etc.) 😁 https://www.youtube.com/watch%3Fv%3DypxEkt33Ytw

I am unaware about any special circumstances about it. There is an air-oil separator box, sitting on top, but that thing is supplying the crank gasses to all the cylinders, not just the first two. In addition, there should be no oil in the intake, except the crank ventilation fumes.

[Dave72dt]

When you pulled the coils and plugs to exchange were the plugs and coil oily?  If so, that alone could have caused the misfire.  Pulling them out without removing the oil first would have dumped that oil onto the pistons giving you unexplained puddles.  Valve cover gaskets tended to leak on those engines.  The variable valve actuators are hydraulic controlled by solenoids and dependent on adequate oil volume.  You can check the VVA rockers when replacing the valve cover gaskets.

[Ivan_B]

@Dave72dt the plug wells were certainly oily, when I first started troubleshooting this problem. But I did clean them out before taking the plugs out, and also cleaned the coils, etc. After some more test-driving, compression testing, etc., the wells weren't oily anymore. So this is not it, I am afraid

 

Update: I removed the intake manifold (this was considerably more difficult than anticipated, but I did it). Also removed the exhaust. I am not seeing any obvious signs of the stem leaks. So, the puddle must be coming through the rings or the head gasket. I'll try to spin the car cold, tomorrow, to see if I can generate an active leak... Or maybe pour something into a couple of cylinders to see how fast it seeps through the rings... 🙄

 

[Ivan_B]

I've finally had a chance to do a bit more troubleshooting (because it was awfully cold in the garage, lately) 😁

Turned 1 and 4 to TDC and poured some diesel into both cylinders. After some time, I confirmed that the diesel is leaking out of 1 at a faster rate (through the rings, I assume). So, at this point, I should either get some new rings and a head gasket, or, maybe try to soak/flush the cylinders with more diesel to see if, maybe, I can clean-out a potentially stuck oil ring 😒

[Sniper]

1 hour ago, Ivan_B said:

clean-out a potentially stuck oil ring 😒

That would be my first choice.  It's relatively cheap and might be the solution.  Especially if it's a new to you engine that you have no idea what it's maintenance has been like (too long oil change intervals come to mind).  Some Marvel Mystery oil in the crankcase would probably help after you change the oil.

[Ivan_B]

2 hours ago, Sniper said:

That would be my first choice.

It's a bit of a conundrum, here. On one hand, I would like to fix this the proper way and also check the valves and clean the combustion chamber, while I am in there. On the other hand, I am afraid that once I take the head off I'll find more problems and things being out of specs, which I really do not want to deal with 😅 

I've had this car for a couple of years, for seldom spare use. I did 2-3 oil changes on it myself... It was not maintained very well, but the insides of the engine (underneath the valve cover) appeared much better than I expected.

[JBNeal]

My rule of thumb is not to invest in a 10+ yr old economy car of any make...I've learned this the hard way, spending waaay too many resources on buggies with very little return other than learning eventually to not repeat this mistake...their emissions equipment and electronics are not the most robust in the world, and replacement costs (if available) are budget busters IMO.  I've worked on enough of these economy cars to recognize where the manufacturers take the value out of the original design to improve profitability and ensure planned obsolescence.  The tote-the-note car lots are littered with these money pits, and I advise ppl to stay away from older cheaper rides because they don't make'm like they once did...I had a cranky coworker lecture me on the economic advantages of owning a beater, but when I pointed out the electronic and emissions related issues, he just blurted out FAKE NEWS with his dismissive hand wave and kept on living in his alternate reality...bless his heart

[Los_Control]

Er oh .... someone get up on the wrong side of the bed this morning .... and such a beautiful day it is 

 

I love old Hoopty's and stand behind them .... in case the brakes fail 

 

My philosophy is they are cheap to run if you take care of them. .... Key is to choose one that has a proven track record for dependability.

When you price a transmission rebuild on a modern car the price is crazy..... the electronics are a headache and expensive.

A replacement motor cost more then my first house.

 

A 1993 Caravan

Rebuilt transmission $2K

Used 135K engine ... $600

New tires $400 .... Shocks, struts, brakes, axles .... every sensor, tps, maf, egr, 02, coolant, .... You can basically rebuild a complete older car for $5K and make a very dependable car out of it.

Basic insurance for the van and my truck is $230 every 6 months. Registration is cheap.

Naturally you need to do the labor yourself ..... One major repair on a 10 year old vehicle can can require a shop to do the repair and exceed $5K

Very cheap to maintain and drive a older vehicle.

 

 

[Los_Control]

2 hours ago, Ivan_B said:

It's a bit of a conundrum, here. On one hand, I would like to fix this the proper way and also check the valves and clean the combustion chamber, while I am in there. On the other hand, I am afraid that once I take the head off I'll find more problems and things being out of specs, which I really do not want to deal with

 

I would just toss a guess out there .... I'm not convinced it is a stuck oil ring .... that might be a common issue on our old iron ... I think I have one on my 1949.

On a modern engine with modern oils .... I do not think so, or it would be my last possible guess.

 

You never did post what the compression readings were.

Anytime two adjoining cylinders show less then normal compression and those 2 cylinders have the same compression .... good chance it is a blown head gasket.

 

If the gasket is blown between a oil port, it would allow oil to get into both cylinders when the head is draining oil back into the pan on shut down.

My past experience with 4 cylinder engines, not all but some it is common to blow a head gasket.

The small engines do not have a lot of room or surface area to install adequate amount of head bolts.

Then modern engines really do have more compression and work under harder loads .... We get so much more horse power from a engine today then 30 years ago.

Just not uncommon to blow a gasket.

 

If I was a betting man, I would bet on a blown head gasket before a stuck ring. .... Easy fix.

 

[Ivan_B]

19 minutes ago, Los_Control said:

If I was a betting man, I would bet on a blown head gasket before a stuck ring. .... Easy fix.

Okay, good point. There are oil passages between the cylinders, I am just not sure whether or not those are under pressure or not. I'll dry the cylinders, later today, and try to crank it for an extended period of time without plugs. If the oil is leaking from a blown head, I should probably see the two cylinders filling up again.

It make sense for the oil to leak while the car was stationary. The problem is, it was misfiring on idle, and sometimes after driving it for a while too. So the oil that was leaking in there while the car was off must've been long gone by that time. Nevertheless, something was actively fouling that plug causing the misfire. When I did take the plug out, later on, it was visibly wet with oil.

The compression was like 195, 195, 205, 205, top. That was a cold engine cranking like 6-8 times. I also checked it according to the manufacturer specs: above 100 on 3 cranks. Did not bother with all of them, but 1 and 2 were like 140-150, well above the minimum mark. Based on this info, I was really looking forward to those valve stem seals, but I did not find obvious signs of leaks

[Los_Control]

Thats what I was thinking   195, 195, 205, 205,   You would like to see 205 across the board.

The 2 cylinders have a blown gasket and they are sharing compression .... this means they have a larger area to fill "both cylinders"

So rings and valves are doing their job and building compression .... just a larger area so they show 10 psi less.

 

The oil would be leaking into the cylinders and obvious by photos being burnt ... that should cause a misfire code because of burning not as efficient as they should.

 

Sitting here at the bar stool and giving advice ... I say go for it! 

 

My 350 chebby vortec engine has 155 psi and I think that is pretty good .... 205 psi is a lot and goes with the gasket is working harder then other engines theory.

 

For your list of symptoms, sounds like you are right on top of things ... replacing the head gasket now should be pretty painless.

Waiting til later you might see worse symptoms and even engine failure.

In a perfect world, you would pull the head and see a spot where the gasket failed ... just replace it.

 

In my world you might pull the head and then find a crack and now we are going deeper .... I suspect it is just a failed gasket .... check the head surface is flat before going to far.

[Ivan_B]

1 hour ago, Los_Control said:

replacing the head gasket now should be pretty painless.

But wait, there is always an alternative: I can replace just the head gasket and it does not fix the issue... If I am taking the head off, I think it would be very much advisable to pull the rings as well, right? 😆

 

1 hour ago, Los_Control said:

The 2 cylinders have a blown gasket and they are sharing compression .... this means they have a larger area to fill "both cylinders"

That could be the case, but I am pretty sure that 1 and 2 are at the different (opposite) strokes, so I do not believe that we have a condition where they are both closed at the same time 🙄

[Los_Control]

C'mon Ivan .... you making me look bad   .... I'm just a carpenter .... I hack on wood.

4 minutes ago, Ivan_B said:

But wait, there is always an alternative: I can replace just the head gasket and it does not fix the issue... If I am taking the head off, I think it would be very much advisable to pull the rings as well, right? 😆

I do not think so. Your engine is creating 195-205 psi compression ..... rings and valves are working correctly. ..... just a bad gasket.

 

15 minutes ago, Ivan_B said:

That could be the case, but I am pretty sure that 1 and 2 are at the different (opposite) strokes, so I do not believe that we have a condition where they are both closed at the same time 🙄

I can not answer that .... I know what you are saying and what you mean .... I realize those cylinders would be at different strokes ....

I read that 2 cylinders side by side sharing same compression reading is a possible sign for a blown head gasket and they share the compression ..... was 40 years ago.

There was no distinction on how many cylinders it had .... 4, 6 or 8 it all meant the same thing. ..... I give the deer in the headlight look and can not explain exactly why .... just that it has happened since the automobile was invented.

 

 

I think there are at least 6 times in my life, driving old junk .... I replaced just the head gasket .... 5 times worked well one time on a old 1960 chebby with no torque wrench it did not work.

Replacing a head gasket without doing other work is kinda common.

Some mechanics may suggest replacing the entire motor .... makes sense if you are paying a mechanic by the hour ....

If doing the labor yourself, and it fails .... you are out the price of gaskets and some time.

 

Have you checked carpart.com for a used replacement engine? Possibly $700 and has a 90 day warranty .... replacing the head gasket might be $200?

I would at least carefully remove the head without damaging the gasket .... would not be surprised you find a pathway where the gasket has been leaking.

 

For giggles lets google.

 

Is 200 psi a good compression?

 

 

The limit for street engines seems to be around 200 psi of cranking pressure. Numbers higher than 200 psi create excessive cylinder pressure at low engine speeds, which turns the engine into a detonating monster

 

This was written in 2002 ... times have changed .... 155 on my chebby V8 is good, 205 is a monster on you 4 cylinder and a blown head gasket is part of the charm.

[Roofus]

Citation

Je suis presque sûr que 1 et 2 sont à des coups différents (opposés)

Oui, j'avais un joint de culasse qui fuyait entre 1 et 2, la compression était à 0 sur les 2 cylindres

Edited Sunday at 09:24 AM by Roofus

[Ivan_B]

 

11 hours ago, Los_Control said:

C'mon Ivan .... you making me look bad   .... I'm just a carpenter .... I hack on wood.

Los, no such thing intended... Your feedback is very valuable! And, I must point out, this is a somewhat difficult case. Otherwise I would've resolved it a long time ago. A customer service rep., here, usually knows what to do 🙃

 

11 hours ago, Los_Control said:

would not be surprised you find a pathway where the gasket has been leaking.

These engines use a layered all-metal gasket. I've watched a couple of videos of these being removed, and I cannot see anything. It is not one of those cases where you actually see a missing chunk, I am afraid

I did consider swapping another engine into it, the cheapest I could find was about $1k and far away. If I junk the entire car, I'll get about as much for it. And a working car is maybe worth $4-5. But I like it, and was planning to use it...

 

4 hours ago, Roofus said:

Oui, j'avais un joint de culasse qui fuyait entre 1 et 2, la compression était à 0 sur les 2 cylindres

Merci. J'avais également cru comprendre qu'une fuite entre les deux cylindres sur un 4 cylindres ordinaire créerait une situation de non-compression.

[Ivan_B]

The flush did not help. The car starts-up fine, then warms up and starts to miss at idle. Upon further inspection, cylinder 1 has oil inside. I do not see any obvious points where it is dripping from, so I have a pretty strong feeling it is the rings. I believe that I've effectively (or not so much) exhausted all of the other non-invasive diagnostics. Oh well, the head is coming off tomorrow.

[Sniper]

Trust me, a head gasket blown between two cylinders will show a lot more than a 10psi drop in compression and it will knock.