Last line of defense
Your vehicle’s engine operates as a closed system, meaning that all of the oil and coolant in your engine is recirculated and reused and should not escape the confines of your engine. With many metal parts that are attached together, your engine features a variety of gaskets and seals that prevent oil and coolant from leaking out. Simply put gaskets are your engine’s last line of defense for preventing leaks.
If you discover spots of oil in your garage or driveway, it means that a gasket somewhere in your engine has failed and is no longer doing its job. Read on to learn why gaskets and seals can develop leaks and which gaskets are most susceptible to leaking oil.
Why do gaskets leak?
Gaskets have to do their jobs inside of your engine, which is a pretty hostile place to work. Constant exposure to high temperatures, high pressures, vibrations and contact with hot fluids over a period of time will cause even the best gasket or seal to develop leaks. Except for very rare cases of catastrophic failure, gasket leaks start out as small drips that you may first notice as spots under your car. Thesewill destroy the appearance of your parking spot and make you unwelcome to park in your friend’s driveway.
There is a natural tendency to dismiss the importance of small leaks of oil and put them on the list of things to fix later – but resist putting it off. Even small leaks can mean big expenses down the road if they are ignored. What starts out as a relatively easy fix can quickly turn into a major issue. Even a small leak can cause you to lose a quart of oil in no time.
Low oil levels can cause engine problems
We all know that driving with no oil is a recipe for expensive repair bills. But many drivers don’t realize that driving with a lower than normal oil level can also cause higher than normal engine temperatures. Higher engine temperatures may breakdown the lubrication ability of the remaining oil, causing damage to and excess wear of pistons, piston rings, valve lifters and engine bearings. The high engine temperatures may exacerbate the leakage of the gasket, creating a spiraling series of events that will impact your wallet with a hefty repair bill.
Common source of oil leaks: valve cover gasket
If your vehicle is leaking oil, the best place to start to track down the source of the leak is with the valve cover gasket, perhaps the most common source of engine oil leaks. Valve covers are typically made of lightweight aluminum or magnesium and may warp over time, so the surface that mates with the cylinder head is no longer flat, creating oil leaks. In addition, the lightweight material can be deformed by excessive torque on the fasteners holding it in place.
Even if there is no structural issue with your valve cover, the buildup of oil sludge due to prolonged high temperature exposure and pressure increases within the valve cover can cause leaks and failures in the gasket.
If there is an overabundance of dirt around the valve covers, use some degreaser and some rags to clean the area so you can see bare metal near the valve cover/cylinder head joint. Check the area after running the engine for a bit and you’ll be able to see if the valve cover gasket is leaking. If this is the area leaking, before you run out and buy a new valve cover gasket, check the tightness of the fasteners holding the valve cover down. If some are loose, tighten them all down evenly and run the engine again. If it still leaks, then a new gasket is the solution. Use the manufacturer’s torque specifications when tightening. Overtightening may distort the valve cover and gasket, making the leak worse.
Other sources of oil leaks
If the valve cover gasket is not the source of your oil leak, the following gaskets or seals may be likely sources:
- Oil drain plug seal
- Oil pan gasket
- Cam chain tensioner gasket and seals
- Front and rear crankshaft seals
If you are experiencing an oil leak, consult your trusted mechanic. They’ll be able to not only diagnose the problem but complete the necessary repairs. Before you know it, your garage will be free of those dreaded oil stains.
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