2004 Subaru Forester timing belt & head gasket

subaru
forester

#1

This 14 year old car only has 65000 miles on it. When should I get the timing belt replaced? Second, a mechanic recommended that I replace the head gasket. Should I do this at the same time? Thanks John


#2

Around 100K for the turbo engine, but there’s usually a 7 year limit on timing belts, irrespective of miles. It’s only a 2-3 hour job and the belt itself isn’t overly expensive, so good idea to have it done now. I wouldn’t replace the head gasket myself unless there were symptoms. It may never have to be done in the life of the car. But Subie engines do tend to have a tendency to blow the head gaskets, so if you want to be on the safe side you could have that done proactively. My suggestion however is to just keep the cooling system in proper maintenance; i.e. flush and replace the coolant every 2 years, and keep an eye on the dashboard coolant temperature gauge. Any signs of even a tendency towards overheating, take it to the shop immediately.


#3

Timing belt service should be listed in the owners manual or service manual. Usually it’s in the manner of "every xx,000 miles or Y years, whichever occurs first. If it’s never been done, it’s probably years past due. Often replacing the water pump and tension pulley and maybe some seals, and any drive belts or the serpentine belt, are part of a thorough job.

If the head gasket is leaking it should be replaced. That’s a big job and is only done if it’s necessary - not as preventative maintenance.


#4

The term head gasket should be in the plural; as in gaskets.

You never replace one head gasket on a Subaru. Both are replaced even if one is still good.

The usual complaint with Subaru head gaskets is not that they blow. They start weeping oil and/or engine coolant.


#5

Replace the water pump,too. Since the coolant must be drained, it is a good time to replace that as well.


#6

I have an '01 Forester that needed both the valve cover gaskets and the head gaskets replaced right after I bought it from a used car lot (big mistake, lol). If there’s obvious leaks and especially if your oil looks like coffee with cream (that means coolant leaking into the oil), find a good, reputable mechanic in need of a boat payment, and ask him to do a full tear-down of the engine and just replace anything that looks sketchy. (Mine did all the oil seals, the water pump, pressure-tested the head and block and replaced all the spark plugs, about $3500 of work all told.)

According to my research, it’s an issue with the engine design in that range of model years: the gaskets tend to dry out because the oil trickles out of where they are (since it’s a flat four engine), so they often bust earlier than in other cars. EDIT 06/17: Ignore this paragraph, see below.

Other thing to watch for: persistent check engine lights esp. at high mileage. Part of it was a bug in the computer software (there’s a patch available that a Subaru dealer can apply), but in my case it turned out to be a faulty wiring harness that was masking a bad catalytic converter.

Once you’re sure of the engine, though, it’ll run probably for another 150,000 miles.


#7

It’s not the head gaskets drying out that cause the problems. It’s due to using only 6 head bolts per head and not retorquing the cylinder head bolts after a run-in period.

This problem also happened with earlier designs that used 8 or 10 head bolts. At the time Subaru said a head bolt retorque was not necessary on hydraulic lifter engines but was recommended with solid lifter engines.

So what happened? The hydraulic lifter engines started having head gasket leaks and the Subaru recommendation was then to retighten the head bolts.
The ones that got a head bolt retorque never failed short of severe overheating.


#8

Would it make sense for the OP to retorque the head bolts on a 14 year old engine? My instinct would be to not do it on an older engine. The “leave well enough alone” philosophy. But I’ve never tried it either.


#9

A timing belt is I believe 3hrs book rate.

A head gasket is over 12-16 hours and the 3hrs goes away. I don’t see the economics in this. Make sure to replace your coolant and throw Subaru coolant conditioner in they recommend (aka stop leak).


#10

Thanks for the correction. Like I said, mine was in considerably worse shape when I bought it than the OP’s apparently is. Really surprised his mileage is that low.