The Subaru Forester has a well-known problem with head gasket failure on their 2.5L H4 engine. This common Subaru problem typically happens at 100k to 150k mile odometer readings. This vehicle was very punctual with a head gasket failure at 153,136 miles...
Why do Subaru have head gasket failure problems?
See our detailed information about Subaru head gasket problem explained.
How to delay head gasket replacement on your Subaru?
Subaru head gasket life can be extended by performing the Subaru factory-recommended coolant replacement every second year and using the special coolant additive produced by Subaru. But even with the best maintenance, these Subaru engines will need head gasket replacement by 150K mileage. Our intent is to fix this problem for the remainder of the vehicle's life around the 300k mile point, or at least another 150k miles.
Diagnosis
Vehicle: 2007 Subaru Forester X, 2.5L, H4 (150CI) VIN(6)
Problem: Customer reports oil leaks from the engine.
When a Subaru Forester head gasket starts to fail engine oil leaks from the head gaskets and is carried back under the vehicle. Often this leaked oil gets onto the hot exhaust system resulting in smoke and a burning oil smell.
Cause: Visual inspection found oil and coolant leaking from failed cylinder head gaskets. We recommended head gasket replacement as soon as possible.
Repair
This Subaru owner wisely chose to replace the head gaskets as soon as possible to get rid of the mess created by the oil leak, rid themselves of the worry about running the engine out of oil and the risk of seriously damaging the engine.
Our Subaru technician removed the intake manifold and cylinder heads. The cylinder heads were to the machine shop for resurfacing to ensure the head's gasket surface is flat and the correct finish for maximum gasket sealing.
NOTE: We do not use failure-prone Subaru replacement head gaskets. We recommend using aftermarket FelPro Subaru head gaskets. We have found they are superior to and last much longer than the Subaru factory replacement head gaskets.
Next the technician removed the timing belt, tensioner, and water pump. Then they cleaned the area of leaked coolant and oil, removed and installed a new water pump, reinstalled the cylinder heads, installed a new timing belt, new timing belt tensioner, and verified the correct timing of camshafts and crankshaft. They finished the timing belt replacement by re-installing the surrounding components, inspected hoses and clamps, cleaned and flushed the cooling system, refilled with the proper mix of coolant and Subaru coolant additive, pressure test the cooling system to check for leaks, and finally, checked the thermostat and cooling fan operation.
Since the engine was already low on oil and it was close to being being due we changed the engine oil and oil filter. As part of our oil change service we performed a digital vehicle inspection report including checking that all lights work, check under-hood fluid levels, and check the tire pressures.
As part of the head gasket replacement procedure the air conditioning system must be evacuated and recharged to allow engine disassembly. Our Subaru mechanic next did an auto air conditioning service which includes inspection of the AC drive belt and refrigerant lines and hoses, evacuate and test for leaks, recharge the AC system with fresh refrigerant, test the AC system performance.
To finish the head gasket replacement the technician started ran the engine to verified there were no leaks. For quality control they test drove the vehicle and checked for any engine management computer error codes. They reported to the service advisor that the repair was successful and the vehicle was ready to be returned to the customer.
Cautions
Frequently check the oil and coolant levels on any Subaru five years or older. And the older your Subaru gets, the more frequently the oil and coolant levels should be checked! Daily if there is any evidence of oil or coolant leaks!
Tips
- The Subaru technicians at Hoover Street Auto Repair have put together a list of Subaru head gasket replacement frequently asked questions to help you make informed decisions about Subaru head gasket repair.
- The customer's concern was the oil leak. But the serious problem was the coolant leak which they didn't notice. The oil leaks are much more noticeable, but a coolant leak can quickly cause a low coolant level and the engine to overheat, resulting in serious engine damage. Subaru overheating can quickly destroy the engine requiring an expensive complete engine replacement. If you have engine oil leaks on a Subaru, monitor the coolant level on a daily basis!
- The oil leaks usually start before the coolant leaks. As soon as the oil leaks start, we strongly recommended weekly monitoring for coolant leaks and getting the head gaskets replaced as soon as coolant leaks start. Besides the environmental harm coolant leaks cause, a coolant leak can result in engine overheating and engine destruction. A Subaru engine replacement costs much more than a head gasket replacement! Also, the coolant can enter the oil system resulting in destroyed engine bearings and a complete engine rebuild. This is a case where the longer you postpone this repair, the more the repair will cost.
- Do regular coolant replacement every two years and use a Subaru-specific coolant additive. It won't prevent Subaru head gasket failure, but it will greatly extend how long the head gaskets last!
Recommended Subaru Repair Shop
We are a Subaru specialist. Contact Hoover Street Auto Repair for all your Subaru repairs and service in Ann Arbor, MI.
Hoover Street Auto Repair
142 E. Hoover Ave
Ann Arbor, MI 48104
(734) 913-6272
Located near the UMich Stadium.
Serving Dexter, MI; Pittsfield, MI; Saline, MI; Ypsilanti, MI.