Brand new JK excessive blowby
 

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Hey everyone I am new here. I got rid of the compass and recently got into a brand new 2018 jkur in may. Currently sitting at 13000km I noticed a fairly large amount of what appears oil dripping from the air box, soaking everything passenger side. I am guessing blow by. Is this common and should I be worried? I will be calling the dealer monday. Oil pressure is good and levels seem low and the oil cap is apparently missing after its first service 3000km ago. Thanks

do not run it without the oil cap. Probably where all the oil is coming from...

Appreciate the quick response. That side of the engine is clean (drivers). All oil is appearing to originate from below air filter box. (Passenger)

Maybe it's leftover from the diff oil mess??? Suggest wiping everything down, and check it often. Windex works well for oily messes. Also, keep a close eye on the engine oil level.

Oil cap missing, is very bad -- I'd be a bit ticked with a new Jeep, best to have it checked at a dealer if you're unsure about the situation.

Stay in touch :cheers:

Are you certain it is oil and not A/C condensation? Kind of looks like my A/C puddles is the reason I ask.

Worst case situation. Can not believe it! Whole air system is filled (soaked!) with oil. Didn't even get far and notice excessive oil loss. Power and everything was normal. Truthfully if it were my gf driving she wouldn't of even noticed.
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Holy moly :eek2: See new things every day.....I don't think I've run across this one. How the heck.....:thinking: I mean, you have what looks to be a lot of oil getting down to the frame. Somebody please explain this one. Is this somehow tied back to missing oil cap creating some freak environment?

Thanks for the response. So it was at the dealership yesterday. I tried explaining that in my non professional head this could only mean faulty pcv valve or blow by, I couldn't understand how a lost oil cap could do it but they ran with that story and blamed the other dealership.They did manage to find my cap deep down somewhere when they were cleaning but that worsens my suspicions more. After cleaning they tell me jeep is safe to drive. Not even a hint of entertaining my concerns on how this could happen. I am going to run it and see what happens I suppose.

That's a lot of oil. I'd wash off the engine before evaluating the fix. But, I agree: Most likely that oil cap was not properly reinstalled after servicing, which led to the mess.

Still could not see it getting in to the intake air box though. Can see it all around the place but not in air box.

I would guess this missing cap was allowing excessive suction through the breather hose on the valve cover that goes to the air box?

Presuming the plumbing is like the 3.8L, as well as most gasoline engines, a hose goes from the downstream side of the air filter to valve cover (or another vent for the crankcase). The flow can go both directions through this hose: If the PCV flows less than the blowby flow, the excess goes into the filter box downstream of the filter (in situations like full power or worn rings). If the PCV flow is greater than blowby flow, clean air is drawn in from the filter box to the crankcase, mixes with blowby gasses and into the PCV. Either way the blowby is ingested for combustion.

So if the cap is off, blowby could escape in some conditions, but I'd agree that most of the time unfiltered air would be entering the cap opening -- Some going through the PCV, and some through that hose to the downstream side of the filter due to the lower pressure there.

All that oil in the box still doesn't make sense to me, might be more to it that we'll never know. Maybe the air filter is restrictive enough that the flow through that hose was high enough to pick up a lot more oil mist than normal??? :cheers:

Cracked oil filter housing. Look in the valley under the motor cover with a flashlight where the filter lives. Rub a q-tip around the bottom of the valley in the front and rear. If it's oily, it's bad. The oil usually runs down the backside off the block.

Any updates?
 

I’ve got exactly the same issue with a 2015 JKU Overland...

Opened the hood and the oil cap is gone and noticed the connection to the air filter was not connected so put a simple replacement cap on and connected her back up again and now I have the air filter box swimming in oil.

Replaced my PCV and installed a catch can and the problem is still there unfortunately.

Next steps is to replace with OEM oil cap to see if maybe excess air from the current non sealed cap is creating a vacuum and do an engine flush for excess carbon and oil sludge as my engine kms is 130000+

I’ll also replace with a slightly higher viscosity oil synthetic 5W30 as I’m in Australia and it’s pretty hot here at the moment around 40+ degrees celsius.

Any results from your issue would be much appreciated and if it’s as simple as putting back on the right fuel cap well at least it’s a cheap fix!