52-56 Subaru Head Gaskets

subaru
by John Volz, owner, Volz Bros. Automotive Repair
After 39 years in the auto repair business and 31 years
as an owner, I’ve had the opportunity to read many
articles pertaining to the technical side of repairing
automobiles. I’ve also had the opportunity to write
many articles relating to shop management. But, this
is my first opportunity to write a technical article.
As a shop owner who specializes in the repair of
Japanese vehicles, I thought I’d share some tips on
Subarus. I started my Subaru experience in 1979
working at a Subaru/Mazda dealership in Southern
California. I can assure you that in 1979 Subaru was
not the most sought after car by consumers. For
example, we sold about 125 new Mazdas each
month but approximately only 10-15 Subarus per
month. Fast-forward 33 years and it’s quite a different landscape for Subaru, which posted sales of
almost 30,000 vehicles in May 2012, up 48% over the
previous year’s number.
Subarus, like many other nameplates, have common problems, one of which I’ll discuss in this article. Head gasket failure has been something Subaru
has struggled with to some extent since
the 1980s. There are
many thoughts as to
why head gasket failure
on Subaru has continued. My theory is that
there is a horizontally
opposed engine with an
aluminum block and
aluminum cylinder
heads, two metals that
tend to move around
more than the traditional
cast-iron block and aluminum heads found on most Japanese cars. A poorly
designed head gasket material also fuels the problem.
There are some other issues that relate to premature head gasket failure. Excessive corrosion has led
Subaru to add more ground straps to the car on the
later models. The discovery of voltage in the cooling
system is believed to contribute to gaskets getting
corroded and failing. Although Subaru did have a
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service campaign
that helped pay for the repairs for some Subaru
owners, the program has pretty much gone by the
wayside at this point.
The head gasket failures
are found in a couple of
different configurations,
the most common of
which is the external oil
leaks at the back of the
cylinder head, generally
most prevalent on the left
head or driver’s side.
The second type is the
external coolant leak, the
coolant leak most common on the driver’s
John Volz is owner of Volz Bros. Automotive
Repair in Grass Valley, CA. The 38-year industry
veteran goes to great lengths to put customers
first and takes pride in offering environmentally
conscious auto service, which he’s done since
the day he opened the shop in 1982. Volz Bros.
specializes in Subaru (the shop’s primary
specialty), Toyota, Honda, Lexus and Acura.
side, as well. Generally, it starts with the oil
leaks, then progresses to the coolant leaking
too. I consider the oil leaks to be of concern,
but when we see coolant leaking, the need for
repair is more urgent. We generally inspect
the heads for the leaks, and then discuss
with our customer the severity of the
leaks. In many cases, you can monitor the
leaks for a period of time before the
repairs are classified necessary or urgent.
The final type of failure is the internal gasket
failure that will produce the classic coolant loss and
overheating. We see many shops try a variety of repairs, including thermostat, radiator and water
pump replacement, only to leave the customer with
money spent on repair bills that didn’t solve the
problem.
The best way to check for an internal head gasket
failure on a Subaru is to check for hydrocarbons in
the cooling system. You can carefully insert the
probe from your smog machine in the radiator (don’t
let the coolant touch the probe). The reading will be
more accurate with the engine fully warmed up. If
the HC levels are above 10 ppm, the head gaskets
are leaking internally into the cooling system.
Subaru changed the design of its head gaskets
around 2003, and designed its own coolant and
special additive to help with the problem. We use
gaskets made by Six Star, which were re-designed
long before Subaru re-designed its gaskets. These
specialized parts are available from Northeast Imported Parts. My point is, for years, Subaru insisted
that the problems we were experiencing were
isolated and not the norm. Northeast Imported Parts
recognized the gasket issues and re-designed the
gaskets early in the failure cycle.
The final topic I would like to discuss before we get
into the repair is cost and how to approach the job.
We’ve performed this repair more than 400 times,
and although each job is unique, the cost for this job
varies, depending on how the job is approached and
the area of the country where the job is being done.
I’ve heard quotes of $1,200–$3,200. I also hear people
trying to do the repair without taking the engine out
of the car, which, in my opinion, is not the correct
way. (We will discuss the reasons as we proceed with
the repair.)
I would guess that 20% of the head gasket jobs we
perform were done at another shop not that long ago
— long enough to get out of warranty, but not long
enough to warrant the cost of the “discounted
repair.” We also see many shops, including the dealer, try to just repair one side, only to have the other
side fail within a few months.
The other issues we see are when the customer
gets the head gasket replaced, only to have other
seals leak soon afterward, that should have been
replaced in the first place. This repair should not be
approached with the mindset of “how cheap can it
be done?” but rather, “what’s the best way to efficiently repair the vehicle so the job will last?” and
“let’s deal with all possible issues that are somewhat
related at the same time.” That said, most jobs require head gaskets, a water pump, a timing belt,
drive belts, thermostat, idler pulleys, a timing belt
tensioner, tune-related parts and machine shop cost.
In our area, $2,220–$2,500 is the normal price range.
DIGGING IN
The Subaru is a 2002 Outback with 109,982 miles. It
has excessive oil leaks from the driver’s side head
gasket and some from the passenger’s side. The
vehicle had been repaired under warranty by the
dealer at about 65,000 miles, and most likely the
repairs were done without taking the engine out
with probably only one head gasket being replaced.
To complete the repair, follow these steps:
1. Disconnect and remove the battery (this will
allow for a proper cleaning of the battery box), drain
all fluids and remove four exhaust flange bolts. I
generally take the whole front pipe off the car. This
allows for better clearance and reduces the chance of
damaging the oxygen sensor wires.
2. Remove the lower bell-housing bolts and motor
mount bolts. Lower the car back down and remove
the radiator, leaving the fans connected. Remove the
air filter box and all intake boots.
3. Remove the upper bell-housing bolts, torque the
convertor bolts (auto trans.) and disconnect the two-
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53
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Photo 1
Photo 2
wire harness plugs on passenger’s side. On the
driver’s side, remove the heater hoses, disconnect
the two fuel hoses and remove the evap hose.
4. From the front of the engine, disconnect the
A/C compressor from the mount and carefully hang
it near the battery box. Remove the alternator completely from the car, remove the P/S pump from the
mount, leave the hoses connected and hang them on
the passenger’s side (See Photos 1 and 2). The
engine can generally be out of the car in about 30-40
minutes. See Photo 3.
5. Remove the intake manifold, timing covers, timing belt and valve cover gaskets. Clean all the debris
from the exterior of the block before removing the
cylinder heads.
6. Remove the cylinder heads, and spend time to
properly clean them and check them for warping or
pitting. I can’t stress enough the importance of this
phase — the surface needs to be thoroughly cleaned.
Many shops or dealerships use a “wheel” to clean
the surface. This may be acceptable on some vehicles, but with the head gasket issue being so commonplace on Subarus, my opinion is that the leftover
swirl marks can affect the integrity of the head gas-
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Photo 3
ket’s ability to seal once it’s re-assembled.
We’ve noticed on the vehicles on which we’re
replacing gaskets that were previously done at another shop that they tend to have the swirl marks on
both the block and the cylinder heads. I don’t suspect
that the swirls will cause an immediate failure, but,
over time, they can contribute to premature failure.
7. Use a razor blade to take the larger pieces of the
old gasket off, then use a sanding block to remove
the remaining debris to get a clean surface. We start
with 220-grit, then we progress to 400 and 600 for
the final cleanup. We use 0.002” as the criteria for remachining. I also consider if the heads have been off
before and if there are the swirl marks from using
the wheel, I generally re-machine the heads even
though there may not be any significant warpage.
This step will add some time since you’ll need to
send it to the machine shop. Our local NAPA Auto
Parts store’s machine shop provides a turnaround
time of about an hour on a pair of Subaru heads for
re-machining.
8. While the heads are at the machine shop, we
focus on the block surface, using the block sander
starting with 220-grit as stated earlier, and finishing
Photo 4
subaru
Photo 5
with the 600-grit. Begin the task of working the surface to remove all dirt and leftover gasket material,
taking your time to get the surface as clean as possible. This is also a good time to clean the engine crossmember area (see Photo 4 on page 54), where much
of the oil accumulates. Also, don’t forget the plastic
gravel shield — another area for oil to accumulate.
9. Next, we focus on the front of the engine.
Remove the oil pump and re-seal it, and replace the
front crank seal.
10. Once the cylinder heads are back from the machine shop (see Photo 5), install them with the new
head gaskets, and install new cam seals. Follow the
head torque sequence. (Note: 2005 and later models
may require new head bolts.)
11. Check the front idler pulleys for roughness (see
Photo 6). There is one cogged pulley and two
smooth pulleys. If the bearings feel rough, I would
replace them. We see quite a few cars come in that
had the head gaskets replaced develop a bearing
noise in the front engine area. It’s a lot more affordable to replace them while the engine is apart.
12. Inspect the tensioner. You’ll generally see some
wetness near the hydraulic area; replace it while it’s
all apart.
13. Install the new water pump, thermostat and
timing belt. The timing belt interval on this generation Subaru is 105,000 miles, so if it’s anywhere close
to its cycle, change it. Then re-install the timing covers and closely inspect the rubber seals. If any oil has
leaked from the oil pump area, chances are the seals
will be swollen and won’t fit properly. Note: We also
check the PCV system to make sure all hoses are
sealing and are clear. Also be sure to install new
spark plugs (many will require new plug wires if
they’ve been contaminated with oil).
14. It’s now time to re-install the engine. Once it’s
installed, add fluids, and then unplug the coil wire
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Photo 6
and crank the engine until you have oil pressure.
After you have oil pressure, connect the coil wire
and start the car. With the battery being disconnected, the computer will need to go through re-learn.
We’ve found that if you let the car idle it will
accomplish this much faster, generally in 5-10 minutes. Avoid touching the throttle to help the
process.
15. While the car is going through re-learn, wait
for the fans to cycle. There are two areas to closely
inspect. One is the power steering pump o-ring
where the reservoir hose connects to the pump.
Movement from removing the engine can cause the
fitting to start leaking soon after the repair. I generally replace the o-ring while the engine is being re-installed.
The other area is the A/C lines where it connects to
the compressor, which is also subject to leaking after
the repair. We generally evacuate, replace o-rings and
recharge with dye as part of our job.
16. Once the car is warmed up and all fluids have
been topped up, I take the car on a road test of
about 25 miles. This generally ensures that the monitors have all run and that any issues can be identified before the car is returned to the customer.
Part of the road test includes a trip to the car
wash. The car is then brought back to the shop,
where the inside of the front window is washed and
the car is vacuumed. The car is then allowed to cool
down for one last fluid check, and we then check for
any software updates from Subaru and re-flash with
our factory tool.
Living in a rural area that receives snow in the
winter months, Subaru is the choice of many car
owners in our area. With Subaru owners being loyal
to the brand, having the skills to repair their cars
right the first time will also build a loyal customer
following for your shop.