There is a list of things that mechaincs often see that seem to apply to almost all of the Subarus. As a general rule if you check these items before buying a secondhand Subaru and they are not an issue it is more than likely that you have a good, well kept car on your hands.The most common and one of the more expensive issues with Subarus is oil leaks and in a lot of cases coolant leaks from the head gaskets. The Subarus run what is called a boxer engine or horizontally opposed engine. For most, the technical mechanic jargon relating to how these engines work will not be relevant but if you’re interested in them google it and read up (we may blog about this in the future). What is important, is to know what your looking for. To locate the leaks we are talking about you will need to view the engine from underneath. On a lot of Subarus a plastic tray is fitted below the engine which will need to be removed to check for these leaks.
The image shows the leak you are looking for. On either side of the engine between the sump and where the exhaust bolts to the head you should be able to see a very obvious line where the head bolts to the engine block. If there are leaks like the one in the image you will see the oil and or coolant along that seam. Its important to note here that coolant leaking from here is unlikely to be coloured as it has mixed with the oil so both liquids will visually apear as oil. Just because its black doesnt mean its only oil.Cost to repair this is substantial. The repair requires the removal of both cylinder heads which can not be done with the motor in the car. This means the motor has to be removed from the vehicle and then the heads removed. Its a very extensive job with the bulk of the cost involved relating to the labour involved. Be very careful before buying a car with this issue.
Oil leak from Rocker cover Gaskets are the next most common issue with these cars. The good news with these is the cost to repair them is far less. These can be repaired for a minimal costs and the engine does not require removal to do it. The price of repairs does fluctuate depending on if the vehicle in question is a quad cam or twin cam engine, turbo charged and non turbo charged engines also differ in cost of repairing this oil leak.What to look for to identify the rocker cover gasket leak. Whilst underneath the vehicle and with the tray off (should be off if your checking the head gaskets) the Rocker covers are on the far ends of the enigne. That is the far left and far right and if they are leaking you will see some things similar to the head gasket issues. In the image, the oil hosing out of the engine is the issue were refering to.
The next most likely issue to find you parting with your hard earned cash is related to the suspension. The repair is relitivly cheap but were probably doing a set of these a week. The part in question is called a Lower control arm bush. Its another comonant located on the underside of the car and is located at the rear of the Front lower control arm. The bush is a rubber componant and in older Subarus were oil filed which means once they bust open the oil leaks out making it very obvious there is a flaw. This is shown in the picture.In new models Suabru did away with the oil filled bush and went to a solid rubber bush, this still did not stop them from failing it just makes it a little harder to identify a faulty one. In newer vehicles your looking for the torn rubber as seen in this image.
Possibly the most common fault with the Subaru range is failure of the 4WD differential. This is the componant of the Subarus that makes them an all wheel drive. The differential that transfers drives to the front wheels are very common for failure but people often miss the symptoms. The symtoms are harsh vibrating and suddle jolting fromt the vehicle when moving slow. This is caused by the gears in the diff unit to lock up. The issue with this is its a costly repair as the unit is combined in the transmission. To repair this the transmisison has to be removed, pulled down and rebuilt. It can get very expensive.To identify this before buying a car, drive it at slow speeds insuring that you are doing lots of slow turns etc. We advise finding a car park and parking the car nose in and tail in a number of times. If the vehicle has this fault it should show up doing these tests. Also be aware that the issue will be moe dominent once the vehicle has heated up. We have found that most of the time this fault will show itself when doing a reverse parallel park.
Rear diff mount bushes are a common issue with older Subarus. The design of the diff mounting set up has changed in more recent years and we suspect this is due to this very issue. The diff mounts are at the very back of the car and are two round black circles that have bolts running through them. They are located just above the rear diff unit. These bushes are known to crack through and cause the diff to swing freely in the back of the vehicle making it feel very loose and dangerous. These cracks are visable just by looking.
Final notes: Its important to note that when buying a second hand car to check the service book that comes with the car. Your looking for regular servicing. However be very careful with this as its easy to fill a book in yourself. Additionally just becuase a service interval is stamped it does not always mean the items on that service were done. Dont assume a service done at 98000 or 106000kms had the timing belt replaced. Make sure you get proof it was done.Finally it is always advised to get any second hand car your thinking of buying looked at by a mechanic. The small cost of a pre purchase inspection can save you thousands of dollars on repairing a jalopy you now own.