[Flyinace1]

I pulled the intake manifold to do my spark plugs and discovered oil in the intake. What would cause this? And how hard is it to fix?

 

[idrive]

Need a little more info.

Year
Miles
Running a standard OEM air filter?
Engine bay clean, not smoking/burning oil?
Engine use much oil in between oil changes?

 

[Flyinace1]

2009 mazda6 s. 180,000ish miles, all stock. I didn't have oil issues until recently. No drips. Oil light will blink on every now and then so briefly it's hard to notice.

 

[Iamadoorknob]

2009 mazda6 s. 180,000ish miles, all stock. I didn't have oil issues until recently. No drips. Oil light will blink on every now and then so briefly it's hard to notice.

Have you ever replaced the PCV valve? If the spring on it is wearing out, that could be letting too much oil from the crankcase into the intake. That would be my first step, since it's such a cheap part. I know all PCV systems have the potential to let some amount of oil into the intake, but anything else would be beyond my limited expertise.

 

[idrive]

^^ Year and mileage this (PCV) is the best place to start .

I would assume if you see the oil light blink you're checking the oil level?

 

[Flyinace1]

Yes, I check the oil regularly. I'll check the pcv valve. I've never changed it.

 

[Get Inline]

Does the oil light start blinking when you are idling or driving? When was the last time you changed your oil? level is good? oil is clean?

To check your PCV valve, with your engine running take off your oil filler cap and put a plastic bag over the opening. If you feel suction trying to pull the bag into the crankcase, your PCV is good. no air suction = faulty PCV.

Have you checked for oil leaks?

 

[Flyinace1]

So, I replaced the pcv valve. It seemed that was bad and it was only a $5 part.
When I changed my spark plugs, I found a thick, kind of sticky oily like substance on the threads and in the wells of all 6 plugs. It didn't seem like fresh oil though. Anyways, I fear I may have a leaky gasket. I'll pull the easier 3 plugs after a little driving and see if anymore has accumulated. If so, how hard is it to change the valve gasket?

 

[Iamadoorknob]

So, I replaced the pcv valve. It seemed that was bad and it was only a $5 part.
When I changed my spark plugs, I found a thick, kind of sticky oily like substance on the threads and in the wells of all 6 plugs. It didn't seem like fresh oil though. Anyways, I fear I may have a leaky gasket. I'll pull the easier 3 plugs after a little driving and see if anymore has accumulated. If so, how hard is it to change the valve gasket?

You lost me with that last question, why would you suspect the valve gasket? Is this some other unrelated thing that you didn't mention before?

 

[Flyinace1]

Is it not the valve gasket that would need replacing if there is oil on the spark plugs?

 

[Iamadoorknob]

Is it not the valve gasket that would need replacing if there is oil on the spark plugs?

Even a perfectly functioning engine can let some oil into the intake. If your engine is burning a ton of oil, or the check engine light turns on, that would be a cause for concern. But since you didn't mention that was the case, I'd not worry about it. Just keep an eye on your oil level.

 

[Flyinace1]

Maybe I should've started a new thread. In the post that I made this morning, I stated that I had changed the pcv valve and that seemed to fix the oil in the intake.

The other issue while I was changing the spark plugs was the goo on the spark plugs. It was thick and kind of sticky, and definitely did not look like fresh oil, but there was a lot on each spark plug and in the wells. I am concerned that oil may be getting past the gasket simply because I don't have a better explanation for what is happened to the spark plugs. If it is a bad gasket, I will need to replace it.

 

[Iamadoorknob]

Maybe I should've started a new thread. In the post that I made this morning, I stated that I had changed the pcv valve and that seemed to fix the oil in the intake.

The other issue while I was changing the spark plugs was the goo on the spark plugs. It was thick and kind of sticky, and definitely did not look like fresh oil, but there was a lot on each spark plug and in the wells. I am concerned that oil may be getting past the gasket simply because I don't have a better explanation for what is happened to the spark plugs. If it is a bad gasket, I will need to replace it.

The oil that was getting into your intake would also end up on the spark plug. That is to be expected. The intake leads to the combustion chamber, which has the spark plug inside it. Normal, and nothing to worry about. AFAIK the only other way to get oil on there is if oil is making it past the piston ring, in which case you'd need to rebuild the engine to replace the ring. But that is not likely.

If you want a better diagnosis please post a picture of the spark plug.

 

[Vipre77]

I think he's saying he's got oil on the top end of the spark plug, not the sparky end. Oil coming in through the intake could foul the tip of the spark plugs if there's enough getting in, but it shouldn't be making its way up the threads and up to the top of the spark plug. If it is leaking that way, then the plugs aren't fully tight and he's got a small compression leak there. Must be minor enough to not cause a noticeable drop in power or cause a CEL. I'd start with the plugs first, make sure they're properly torqued and see if the oil comes back on the top side of the plugs. If it does, then tear open the valve covers to swap the gasket(s).

 

[Flyinace1]

I think he's saying he's got oil on the top end of the spark plug, not the sparky end. Oil coming in through the intake could foul the tip of the spark plugs if there's enough getting in, but it shouldn't be making its way up the threads and up to the top of the spark plug. If it is leaking that way, then the plugs aren't fully tight and he's got a small compression leak there. Must be minor enough to not cause a noticeable drop in power or cause a CEL. I'd start with the plugs first, make sure they're properly torqued and see if the oil comes back on the top side of the plugs. If it does, then tear open the valve covers to swap the gasket(s).

This. The spark tips weren't fouled, it was on the threads and in the wells. So how hard is it to replace the gaskets? I've never done them before.

 

[Vipre77]

Can’t help ya on that one, sorry. I know the plugs in the back cylinders aren’t fun to get at, so I can only imagine the valve covers being roughly the same level of annoyance. I don’t know how much of the intake plumbing you need to remove, if any at all, to get at it. I don’t think I have my old shop manual anymore to reference, unfortunately.