4.0 Head Gaskets

[M6F]

Found some mayo in the oil cap of my '07 Ranger so i think the head gaskets might be on the way out. I read somehere that the 4.0 SOHC engines have to be pulled out to do the gaskets on these, is that true? If so, do you think it's worth just getting a loe mileage engine and swapping it out? I don't have much money to fix it and would have to get someone else to do the work as i don't have the tools or space to work on it

 

[RonD]

"Mayo" on the underside of oil cap means PCV system is not working well
Get a new PCV valve and clean the PCV hoses

Low compression misfires, overflowing coolant tank, white smoke out of the tail pipe and coolant in the oil pan(milkshake) are the different signs of blown head gasket

Yes, it would be easier to redo head gaskets with 4.0l SOHC with engine out, but its possible to do it with engine in place

 

[M6F]

Interesting, i hadn't heard of the PCV valve before. I'll take a look at it, thanks!

 

[RonD]

The PCV(positive crankcase ventilation) system uses engine vacuum to pull Blow-by gases out of the crankcase and valve cover areas so they don't escape into the air

Every time a cylinder fires, some of the gases(exhaust) will "blow by" the piston and rings and into the crankcase
Not a defect just a fact of trying to contain an explosion, lol

For years this "exhaust" was just vented to outside air
PCV system was added to reburn the Blow-by gases by sucking them into the intake

PCV system also sucks in fresh air via the Breather hose

Exhaust gases contain water vapor, this is why tail pipes drip water and exhaust systems rust from the inside out
The PCV system pulls that water vapor out with the blow-by, when its working

If the water vapor stays in the engine then it will condense on cooler surfaces...................like the oil cap's back side
And you get the "mayo" gunk

PCV Valve should be cleaned every oil change and replaced every 3 or 4 oil changes also hoses cleaned

 

[M6F]

Got it, thanks! I've never cleaned it and i doubt the previous owner did either so it could be time for a replacement. I'll chuck a new one on and see how she goes. Might solve my high idle problem as well by the looks of it

 

[Angie]

If the water vapor stays in the engine then it will condense on cooler surfaces...................like the oil cap's back side
And you get the "mayo" gunk


This was exactly my first thought... cheers

 

[Broosedamoose]

Just did the head gaskets a few months ago and didn't have any issues doing them with the engine still in the truck.