Blowing Oil Out Rear Valve Cover?

Started by Dirtymaid, June 19, 2026, 12:16:51 PM

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Dirtymaid

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Dirtymaid
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2016 zforce 800
4k miles.

Just started blowing oil out the rear valve cover.

Replaced the valve cover, valve cover gasket, shoulder bolts/bolt o rings, oil filter and oil

Let it idle for 15 minutes with no leaks but as soon as I start driving it the leak returns to the point it's dripping/running out all over.

Crankcase breather tube in the airbox seems to be clear and blowing out a small amount of air

I've heard of checking the drain holes or checking the relief spring?.

Any help or ideas would be appreciated. Thank you for your time .

NMKawierider

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2015 ZForce 800 53 (Trail)
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NMKawierider
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Better check if the crank case vent is kinked or blocked is some way. If pressure can't be vented, it will blow out the weakest places first and that would be the o-rings on the valve covers..next is oil seals being flipped so better check.
2015 Z Force 800 53/Trail EPS
Custom Air Intakes | Custom Exhaust Mod | SuperATV Harness | Custom Fenders | Custom Skid/Rock Sliders | 27" GBC Grim Reapers | Seizmik Mirrors |Конструктор Doors | Dr Pulley Sliders | 1.5" Wheel Spacers | BENZ Silencer (as needed) | SATV Flip Windshield W\ Rear Shield | Dual Light Bars | Diamond Plate Storage |7- 9.7" GPS Systems | Bandit Springs Rear & Gen-3 Shocks Front | Cage Chop Mod

My Videos On YouTube

Dirtymaid

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Dirtymaid
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The crank case breather tube connected to the airbox seems to be clear and I can feel air blowing out of it

NMKawierider

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NMKawierider
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Quote from: Dirtymaid on June 19, 2026, 12:33:50 PM
The crank case breather tube connected to the airbox seems to be clear and I can feel air blowing out of it
Follow it all the way to the engine. Make sure there's nothing wrong. It's likely the cover has a crack so pull it, clean it up and look close at that spot with a magnifier. If nothing then look at that spot on the head. 
2015 Z Force 800 53/Trail EPS
Custom Air Intakes | Custom Exhaust Mod | SuperATV Harness | Custom Fenders | Custom Skid/Rock Sliders | 27" GBC Grim Reapers | Seizmik Mirrors |Конструктор Doors | Dr Pulley Sliders | 1.5" Wheel Spacers | BENZ Silencer (as needed) | SATV Flip Windshield W\ Rear Shield | Dual Light Bars | Diamond Plate Storage |7- 9.7" GPS Systems | Bandit Springs Rear & Gen-3 Shocks Front | Cage Chop Mod

My Videos On YouTube