Why Is Your Vintage Car Going Through Oil?

Vintage cars have a reputation for being oil hogging machines. This is not altogether surprising. Most of these engines have thousands of miles of wear on them, years of rust, or both. Automakers were also not designing classic car engines to last for nearly 100 years. Their focus was on producing an engine that worked well and was easy to assemble.

The wear, tear, rust, and weakening of aging materials means that your vintage car may be going through excessive amounts of oil. Cars that are burning oil or leaking oil can be an annoyance. You have to remember to constantly add oil before driving, which can become expensive, but forgetting to add oil can make problems significantly worse.

In some cases, excessive oil burning can indicate a larger engine problem, and leaving it untended can make the issue worse. Taking some time to investigate the cause of burning or leaking oil, and making any fixes if possible, can save you long term hassle and help your classic car run better.

Possible Causes of Engine Oil Consumption

Excessive oil consumption in vintage cars is almost always due to a problem in the engine, so this is where you will start to look for the issue. If you noticed a leak after finding oil on your garage floor or driveway, a worn, broken, or improperly fitted part in the engine is most likely the cause. But if you have blue smoke coming out the exhaust or suspect you are burning oil for another reason, the issue could be more complicated.

As a starting point, start by looking for all of these common issues with your engine, and note that some of them may require removing the engine:

• Worn or Broken Components

On a classic car, it is expected that the engine will have wear due to aging and miles driven. These various engine components are among the most likely to wear down, crack, or deteriorate and lead to leaks:

• Piston Ring
• Crankshaft Throws
• Oil Seals
• Valve Guides
• Valve Stem Oil Seals
• Rod Bearings

Several factors can cause these different parts to become worn. First, all mechanical parts wear over time, especially in an engine with so many moving parts and in older cars that may not have had the most efficient engines.

If your car has been burning or leaking oil for a while, the engine often lacks the lubrication it needs, compounding that wear and tear and escalating the issue. Excessive heat when the car is running can also cause cylinder walls and other metal parts to warp.

• Bad Installation

This troubleshooting step may be the place to start if you have recently done work or had work done on your engine as a new part may not be in right. But a bad part installation can also start causing problems years after the initial work, or fall out of alignment with continued use.

All of the following issues can cause burning oil or leaks if they are not correctly placed and aligned:

• Piston rings installed in one of a variety of incorrect configurations.
• Not enough clearance for the ring gap.
• Misalignment between the block and crankshaft.
• Incorrect installation of intake valves.

Also check to make sure each necessary component is installed. If you have taken your engine apart and put it back together, missing a small seal or ring is not an uncommon mistake to make.

• Clogging

Engine sludge - caused when oil breaks down - and other debris like particles from combustion can clog up your engine. In addition to being a problem now with burning oil, any clogging in the engine can lead to very expensive problems as the sludge causes oil starvation, grinding parts, and seizing, as well as simply more sludge buildup.

The areas that most often become clogged are the oil drain holes, PCV valve hose, or oil breather system, if your car has one. You can clean the drain holes to clear them, but it is often best to replace the PCV valve hose and oil breather. Fixing these issues can also help improve your mileage.

• Problems with the Oil

If your engine looks fine, has all the necessary parts, and is clean, the issue may be with the oil itself. This can happen if you have:

• Too Much Oil - When the oil level is too high, it comes into contact with the crankshaft which then aerates the oil as it moves. This fails to lubricate the engine, creates hazardous pressure, and causes the oil to burn. Check your dipstick to make sure the oil level is right.
• Low Grade Oil - Using a low quality motor oil in your vintage car will result in poor heat resistance. At even minimal heat, oil can begin to evaporate, changing the consistency and resulting in leaks.
• Crankcase Dilution - This occurs when fuel gets into the oil, possibly through a leaking fuel injector, worn piston rings, incomplete combustion, or idling the engine for long periods of time. A fuel analysis can help you determine if this is occurring.
• Need an Oil Change - As fuel combusts in the engine, it can leave behind carbon particles in the motor oil. The dirty oil can eventually become sludge and clog or seize up your engine, which leads to burning oil or leaks.

The fix here could be as simple as getting an oil change (and continuing to do so on a regular schedule) or siphoning out extra oil. If the oil has become polluted, an engine flush or full scale cleaning of the engine might be necessary depending on the reason for the oil problems.

• Other Common Causes

Many of the above issues will put you on the right track as you troubleshoot engine burning problems. But there are a few systems outside of the engine that can cause these issues as well. If you have surveyed your engine and found no reason for burning oil, test your ignition timing as a late ignition can burn oil.

You may also want to see if your cooling system is failing, letting small areas of your engine overheat. Like engines, cooling systems in classic cars can malfunction over time and cause problems in the engine.

Fixing Oil Consumption Problems in a Vintage Car

Depending on what problems you diagnose with your vintage engine, the necessary repair may be anything from replacing a part to rebuilding the engine. If you can determine the reason behind the leak or burning oil is not doing any damage to the engine, you might even elect not to make a fix. Just be sure that you keep the oil level consistently filled.

If you have discovered a problem with the engine that can cause long term damage or keeps your car from running properly, you may elect to fix it yourself or take it to a trained mechanic. For those rebuilding engines on their own, many vintage car enthusiasts swear by using original parts or engines sourced from contemporary vehicles, but it is also possible to find parts constructed with current technology to fit some vintage cars.

For all of the other parts you need to keep the engine in your classic car running, Vintage Auto Garage is your best choice for vintage car parts online. We offer alternators, starters, relays, and fuel pumps for carburetor engines with options to fit Chevrolet, Ford, Buick, Pontiac, Hudson, Oldsmobile, and more. Look through our website or call us for personalized assistance in finding the parts you need.