Back to all

PCV Valve Replacement

August 21, 2022



Hello Oswego, let's talk about your often-unnoticed but extremely important PCV valve. The energy from exploding fuel is what powers your engine. But some of the vapors from the explosions escape into the lower part of the engine, called the crankcase. The crankcase is where your engine oil hangs out. These gases are about 70% unburned fuel. If the gases were allowed to stay in the crankcase, they would quickly contaminate the oil and turn it to sludge. Oswego folks know that sludge is one of the biggest enemies of your engine, clogging it up and eventually leading to expensive failures. Also, the pressure buildup would cause seals and gaskets to blow out. Therefore, these gases need to be vented out.

Pre-1963, gasoline engines had a hose that let the  fumes vent out into the air. In 1963, the federal government required gas engines to have a special one-way valve installed to help reduce dangerous emissions. (Can you imagine how polluted our Illinois air would be if every car had been releasing those poisonous fumes for the last 50 years?) Diesel engines are not required to have these valves.

The positive crankcase ventilation (PCV) valve routes crankcase gases through a hose and back into the air intake system where they are re-burned in the engine. Fresh, clean air is brought into the crankcase through a breather tube. It's really a pretty simple system, but it does the job. The re-circulating air removes moisture and combustion waste from the crankcase, preventing sludge. This extends not only the life of your oil but the engine as well. The PCV relieves pressure in the crankcase, preventing  oil leaks.


Eventually, the PCV valve can get gummed up. Then it can't move enough air through the engine to keep it working properly for Oswego vehicles. If the PCV valve is sticking enough, you could have oil leaks, excess oil consumption and a fouled intake system. If you experience hesitation,  surging or an oil leak, it may be a sign of PCV valve problems. Your vehicle's owner's manual may give a recommendation for when the PCV valve should be replaced - usually between 20,000 mi/32,000 km and 50,000 mi/80,000 km. Unfortunately, some don't list a recommendation in the manual, so it can be easy to overlook.


Many PCV system problems can be diagnosed by our technicians at Tuffy Tire & Auto Service Oswego . Fortunately, PCV valve replacement is both quick and inexpensive at Tuffy Tire & Auto Service Oswego. Proper oil changes will greatly extend the life of the PCV valve. Skipping a few recommended oil changes can allow varnish and gum to build up in the valve, reducing its efficiency. So now when your Oswego service technician tells you its time to replace your PCV valve, you will know what he's talking about. If you have had your car for a while and this is the first you've ever heard of a PCV valve, ask your technician to check yours out or call Tuffy Tire & Auto Service Oswego at 630-898-6220.

Tuffy Tire & Auto Service Oswego
1555 US Highway 34
Oswego, Illinois 60543
630-898-6220

More articles from Tuffy Oswego

Too Hot to Handle (Vehicle Overheating)

June 15, 2025

In the hot weather, seeing steam coming from the engine compartment is something we all dread. No one wants that to happen to them. But if you know the signs of overheating and how to deal with it, you may be able to reduce the risk of damage to your vehicle, maybe even prevent getting stranded ... More

Losing Your Cool (Why is My Air Conditioning System Not Working?)

June 9, 2025

When you turn on the air conditioning in your vehicle, you expect cool air to come out of the vents. You depend on it, especially in hot weather, but it can also be important in humid weather when you need it to help defrost your windows and windshield. The air conditioning system has a lot of p... More

Motor Oil?The Synthetic Advantage (Synthetic oil vs Conventional)

June 2, 2025

Youve probably already heard that regular oil changes are extremely important for the health of your vehicles engine. Thats sound advice. But what you might not know is when it comes to motor oil, the real thing may not be the best thing for your engine. There are different types of motor oil: ... More