Subaru Head Gasket Failures
Subaru’s are great year round cars for New England. On any giving day you drive by our shop it can look like a used car lot for Subaru’s. We do service that many.
As I said they are great cars, but like all things good they’re not perfect.
There are three repairs that strike fear in the hearts of Subaru owners. If you own a Subaru, the odds are not in your favor of avoiding one of the following repairs:
The top three most expensive problems with a Subaru
1. Timing belt replacement. (Necessary maintenance)
2. Converter replacement. Short trip driving, ignoring a check engine light or poor maintenance are a factor. Other times it’s just dumb luck.
3. Cylinder head gasket replacement. The “luck” thing plays into this in a couple of ways. But, it is helpful to follow the recommended service/maintenance schedule provided by Subaru.
All of these items can be costly repairs, but today we’re going to talk about cylinder head gaskets. The other day a Subaru wagon came in for a basic service. The customer also complained of a burning smell coming from the vehicle. With the vehicle on the lift, inspection found that engine oil was leaking onto the exhaust system.
Where was the oil leaking from?
The head gaskets, in fact, oil was leaking from both sides of the motor.
Let’s Take a Look
The next 2 images are from the driver’s & passenger side cylinder heads showing the area where the leak was occurring. This condition is more of a Subaru problem and is rarely seen on other vehicle makes. (click on image for better view)
So why is that? When it comes to Subaru’s they are known for problems with their head gaskets.
Subaru’s head gasket problems generally come in 2 flavors.
1. Head gasket failure resulting in an oil leak, as you can see by the images shown.
2. Head gasket failure that allows combustion gases to be pushed into the cooling system, or coolant being allowed to enter the combustion chamber.
In either event, to correct the problem requires removal of the cylinder heads to replace the gaskets, which is no small task.
Head Gasket(s) Replacement 2008 Subaru Outback with a 2.5 liter engine, near zip code 03261 or plug in your Subaru’s info
Let’s Get the Engine Part…
With the cylinder heads removed inspection of the cylinder head gasket found the cause for the leak. The sealing material on the gasket had failed. The next few images show (click on image for better view) the area that the gaskets had failed, it is fairly easy to see. As you look at the images another question may come to mind.
What is that material that looks like paper on the cylinder head gasket for?
That material actually has a couple of responsibilities, aiding in sealing but it also is designed to allow for movement of the cylinder head. Yes, movement of the cylinder head.. More on this in a minute.
As mentioned previously, this has been an ongoing problem with Subaru’s. You can get the replacement gaskets from Subaru; they have improved the design, but there is better product out there to help prevent a re-occurrence of this problem.
With some research we have found an aftermarket head gasket that is of better quality and has been providing us and our customers with excellent service.
What makes the aftermarket gasket so different?
How Do They Measure Up?
You’ll note the gray dots on the gasket, these are the points where the measurements were taken. The next 3 images show readings/measurements found. As always, (click on image for better view)
Run your mouse over the images to see the measurements recorded. Okay with that out of the way, let’s take the readings/measurements in the same places on the aftermarket gasket.
The first thing you’ll notice is the gasket is thicker in all 3 places. Run your mouse over the images to see the measurements recorded. You remember the picture that showed the area that failed in the old gaskets? Now look at that same area on the aftermarket gasket compared to the Subaru factory gasket. The design has been changed to improve the sealing in that problem prone area. (click on image for better view)
Got-to Slip and Slide
The aftermarket gasket is a 3 piece gasket while the Subaru is a one piece gasket. Both gasket’s have the silvery looking Teflon looking coating. The coating on the old style head gaskets looks like paper peeling off in an earlier photo of the old & failed head gasket.
The coating is needed to allow the cylinder head to move where it sets/seals to the engine block. Why is this? The cylinder head will heat up at a different rate than the engine block during warm-up. As the aluminum heats up, it expands in size. As you can guess the head will grow/expand faster than the engine block.
We’re not talking big numbers here. You could not see change with your eyes. But in the world of engines there is a lot going on!! I will not bore you with those details.
In any case, the coating on the head gasket allows for some slip n slide. This slip n slide is also part of the problem. The coating doesn’t last forever under these conditions.
Three is Better Than One
The aftermarket gasket by being a 3 piece gasket allows for more slip-n-slide. The center part allows 2 more slip-n-slide surfaces to help reduce work the coated surfaces that seals against the cylinder head and engine block.
If you took the time to visit the Repair Pal web site and plugged in the information provided you’ll agree that if this repair was being performed on your Subaru you would want the aftermarket head gasket installed.
When it is All Said and Done
As a reminder, Subaru has learned from the past and has made corrections in their product. While technicians were waiting for a solution from Subaru, a replacement aftermarket gasket arrived. The aftermarket gasket is a strong performer and our gasket of choice when it comes to replacement head gaskets on a Subaru.
Note; that cylinder head gasket technology is far more complex than the small part we touched on in this article.
You’ll find several images from the head gasket replacement on the Subaru, see below.
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