PCV Valve Replacement
November 20, 2020
Hello Troy, 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. Troy 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 Michigan 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 Troy 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 Auto Lab Troy . Fortunately, PCV valve replacement is both quick and inexpensive at Auto Lab Troy. 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 Troy 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 Auto Lab Troy at (248) 643-7690.
Auto Lab Troy
2790 West Maple Rd.
Troy, Michigan 48084
(248) 643-7690
Need Service?
More articles from Auto Lab Troy

No Charge (Why Won’t My Battery Hold a Charge?)
April 15, 2026
When your vehicles battery is dead, it leaves you with that horrible, helpless feeling. A dead battery means it wont hold a charge, and there are several reasons it wont. One is age. Batteries have chemical and electrical systems in them that create power, and as time goes by, they wont work we... More

In the Red (Why a Vehicle Overheats)
April 14, 2026
Heat is one thing that can damage a vehicle, especially if a problem isnt taken care of soon. Be on the lookout for signs that its getting too hot in some parts of your vehicle, starting with the most obvious one: the heat gauge/warning light on your instrument panel. When you see that heat gaug... More

Stop! And See Us (Brake Pad Replacement)
March 29, 2026
If youve ever driven a bicycle with hand brakes, youll probably understand how the brake pads on your vehicle work. Bicycle brakes use a system that squeezes the bike wheels rim with a pair of cushioned pads activated by your hand squeezing the hand brakes on your handlebars. The friction of tho... More
