Skip the auto shop - Our mechanics make house calls

Q: blow by around pcv and around oil breather cap.

asked by on

I have a 1983 5.0 convertable H.O 302 with 289 heads and chevy valves erson roller rockers re-grind cam a little one no big jump in cam. i did not rebuild the motor. New high volume oil pump. I am gettig blow by around my pcv valve and my oil breather/fill cap.I know my valves are out of adjustment can this cause blow by. Is the alternative possible cause bad rings? is there other reasons for blow by such as vaccume leaks or timing or anything besides rebuilding it
My car has a manual transmission.

Hi there. Engine blow-by is the result of combustion gasses getting past the piston and/or piston compression rings, this builds crankcase pressure. The PCV (positive crankcase ventilation) valve system is designed to remove the pressure and recirculate the gasses back into the intake manifold. When the blow-by overcomes the PCV system, evidence will be seen at the PCV, oil cap, and KV breather filter. Excessive blow-by generally is an indication of worn cylinder walls and/or piston rings. The modifications to the upper engine and improperly adjusted valves are probably enhancing the blow-by. I recommend having your vehicle’s engine blow-by be diagnosed and repaired by a certified technician, such as one from YourMechanic.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: Fuel pump will not stop running when the engine is turned off

It sounds like you have an intermittent short in the control circuit of the fuel pump relay. It may be easier to just remove the fuel pump relay when you stop the car instead of removing the negative terminal each...

Q: Water it is not cycling to the motor is just staying in the radiator and then boiling over why is this and what can I do to fix it

Hi there. Assuming that the new water pump was correctly installed, it's more than likely that you have a blockage or obstruction of debris inside the heater core, the radiator itself or the cooling system hoses. The best way to...

Q: Why won't my truck charge the battery?

Hi there. Several situations could prevent adequate charging from an otherwise healthy electrical system. These include poor connections at the batter posts, power cables at the alternator, ineffective grounding between the battery, chassis, and engine (good connections and large enough...

Related articles

How Do Power Car Windows Increase Passenger Safety?
Power windows are responsible for approximately 2,000 emergency room visits every year. When a power window closes, it exerts enough force to bruise or break bones, crush fingers, or restrict an airway. Though...
How Long Does a Heater Control Valve Last?
Keeping the right amount of coolant in a car is essential in keeping the engine at the right temperature. Failing to have the right amount of coolant or even bad elements...
P2428 OBD-II Trouble Code: Exhaust Gas Temperature Too High Bank 1
P2428 code definition A P2428 trouble code signifies that the PCM has detected a problem in the exhaust gas temperature sensor circuit in bank 1, which subsequently contains the number one...