How to check the car engine when buying a used car
Imagine, you are shopping for a used car. You enter the dealership and see that nice-looking car. You love it from a first sight. Meanwhile, the salesperson hanging around and telling you that regular story that, the car was lady driven and the engine works like a clock and this is only "Today special" - "We need to clean inventory!" and that you are so lucky because they are selling it very cheap - "We even lose money on this deal!" and that you have to give a deposit right now or else you will regret about it for the rest of your life! Sounds familiar so far?
You decided - "deal!" - shaking hands, you're happy, the salesperson is happy. Finally, you got your new wheels.
Few weeks later you notice blue smoke when you're starting the car in the morning.
Few months later you discover that there is no oil left in the engine and finally got your car towed to the garage. "The engine is gone - has to be rebuilt" they diagnose.
In fact it's quite common scenario.
Read few tips that may help you to discover potential problems. However, I recommend to have the used car properly inspected by a mechanic prior purchase.
• Check oil level and condition
• Look for leaks
• Check visible internal engine parts
• Timing belt
• Check the smoke
• Engine noises
• Warning lights "check engine" etc.
• Test-driving the car
• Mechanical inspection
• Do's and Don'ts
Things you should know before going to check a used car
When buying a used car, without a doubt, first check a car history records.
Some cars may have been flooded - worthless to buy.
Others were written off by insurance due to serious accident. Many cars have altered mileage and so on.
Follow this link to learn more How to check the used car VIN history report
If looking at the used car you noted any problem with the engine (e.g.: major oil leak or
strong noise) or any abnormal behavior don't let the salesperson to mislead you. They may tell you, for example, that the leak is "overflow from the recent oil change" or "the noise will disappear later by itself" or something like this. Generally, such defects never disappear
by itself. If you have hesitation, move on - there are so many cars available.
Ask for service records if they are available. Look for oil change intervals - was engine oil changed regularly?
Maybe driving a thousand miles over suggested oil change interval won't cause any significant damage, but three-four thousand miles over recommended oil change interval can cause serious problems in the future. Keep in mind, that modern engines, especially those with turbo charger are sensitive to the oil change interval.
How to check the oil level and condition
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Park the car on a level spot, turn the engine off and set the hand brake. Locate the engine oil dipstick, pull it out, wipe it off with clean cloth and insert it back. Pull it out again and have a close look. If you've never checked the oil level before, follow this link for detailed guide How to check engine oil.
If you find engine oil looks completely black (although for the Diesel engine black oil is normal) and (or) the oil level is very low (left picture) - suspect excessive oil consumption and (or) lack of maintenance. In either case the engine will more likely to have problems in the future. Another sign of poor maintenance would be dark stains (carbon deposits) covering the oil dipstick along its length.
Well maintained engine will more likely to have cleaner oil and the proper oil level (right picture), although is doesn't necessarily mean that the engine is in good shape; engine oil could have been changed recently.
Look for leaks
Look for possible oil leaks. If the engine looks very clean and shiny it doesn't mean it has no leaks. Probably it has been shampooed. Most of the dealers shampoo the engine before putting a used car for sale. But there is the trick - look underneath the vehicle using your flashlight. Check the lower part of the engine and transmission. Everything has to be dry. There might be slight wetness which is not that bad, but there should be no leaks. See any leaks? Oil drops on the parking space? This may indicate a problem. Water dripping from the air conditioner drain tube with running A/C is normal; the air conditioner drain tube is usually located on the passenger side of the firewall.
If it's possible, look at the internal parts through the oil filler neck
(Don't open the oil cap while the engine is
running!)
With the engine turned off, try to open the engine oil filler cap and look inside through the oil filler hole. Use a small flashlight. If it's possible to see any internal
parts there, check their condition. What you are looking for is the sludge - this thick black buildup on internal parts you can see on the lower photo (this is how the sludged up engine looks inside, with the valve cover removed). If you see a lot of black oil sludge buildup inside the engine it means
that either engine oil has not been changed in a long time, or the engine has been overheated, or poor quality oil was used. |
Timing belt
Many cars, especially with four-cylinder engine, have a timing belt that needs to be replaced at a certain interval - usually between 60,000 and 100,000 miles (100,000 and 160,000 km). If it wasn't replaced by the previous owner, you will have to do that. It's difficult to check it on the car because the timing belt is protected by the protective covers. The only way is to ask the previous owner if they have a receipt. Sometimes though, dealers place the timing belt replacement sticker somewhere on the top of the engine (see the picture) that indicates the date and the mileage when the belt was replaced.
Check the smoke
blue smoke at start-up may indicate engine problems - avoid such a car.
A black smoke means the engine consumes too much gas - possible problem with fuel injection. A white steam (smoke) with sweet smell coming from the exhaust even after the car is fully warmed up may indicate a bad head gasket. |
Listen for noises when the engine is running
There shouldn't be strong noises, coming from the engine under any condition with no matter is the engine cold or hot. By the way, knocking or tapping at a cold start is one of the indicator of poor maintenance. Knocking, tapping or rattling noises indicate excessive wear of internal engine parts. Whistling may be caused by loose belt. If the engine makes too much noises, avoid buying such a used car (however, Diesel engines are always more noisy, it's normal).
Look at the instrument panel
There should be no warning lights such as "low oil pressure," "low oil level," "overheating," "check engine" or "service engine soon" etc. on the instrument panel when the engine is running.
I receive lot of questions about "check engine" or "service engine soon" light.
You may find the explanation what "check engine" means in this article Check Engine light.
If the car has "check engine" or any other warning light
coming on while driving, have the proper diagnostic done before deciding to buy the car; in some cases the problem could be very costly to repair.
Test drive
Try to test drive a car for as long as you can. Try to accelerate, decelerate, take it on the highway if it's possible. The more you drive, the more chances you discover possible problems. If it's your first car, try to test drive few different cars of the same model to have better idea. If you feel anything that may indicate possible engine problem (e.g. vibrations, stumbling, misfiring, delay during acceleration, rattling noise, smoke, rough idling, etc.) avoid buying such a car. If you have any hesitation about the way the car drives, shop around, there are plenty of used cars available. Sometimes a sales person may try to push you to buy a car today and now because "tomorrow I won't give you this price" or "I have the customer who will buy this car tomorrow" - Don't rush, take your time to think, the more you shop around, the more chances to find the right car for the right price.
Mechanical inspection
As a last step prior buying a used car, have the vehicle inspected by an experienced mechanic of your choice.
Do's and Don'ts
- Don't buy a car if it smokes from exhaust.
- Don't buy a car if the engine is too noisy.
- Don't buy a car if the engine has been overheated.
- Don't buy a car with high mileage; more than 155,000 miles or 250,000 km is probably too much.
- Do hire someone knowledgeable to have a vehicle inspected before you buy it.
