i saw an 88 chevy pickup truck advertised on craigslist for really cheap. the only thing wrong with it was that it spit all the oil through the dipstick tube when you started it, without disturbing the dipstick itself. it’s a 4.3 litre v-6. I remember back to my turbo mustang days, where the same thing happened to me. it turned out to be the pvc valve was for a non-turbo engine and let the air flow the wrong way, and pressurized the crankcase. of course the 4.3 L is not turbo, so i can’t figure out why it would be pressurized. could you tell me?
Stuck PCV valve or broken piston rings.
The pcv valve is in one valve cover while the unrestricted vent to the air filter duct is in the other and likely plugged.
The pcv valve lets the bypass exhaust out of the crankcase. It is connected to the intake vacuum to increase the flow. A plugged pcv valve, or, one with too little flow, MAY let the crankcase pressurize and blow oil out of the oil fill tube. The other possibility is, there may be excessive blowby from worn piston rings. To check for worn piston rings, you could do vacuum and compression tests. Of course, vacuum tests are much easier. See your Chilton’s for instructions.
[b]Does this happen everytime the engine is started? Or does the vehicle have to sit for awhile for it to do this?