I pulled the heads yesterday on my 98 Forester because of the typical head gasket symptoms (engine out of the car) and noticed that all of the gaskets seemed to be assembled dry. I have the overhaul gasket set so what gaskets require dressing and what type? My shop manual doesn't mention it. I'll be taking the heads to a machine shop this week for resurfacing, pressure testing, and installing stem seals. Also, what are the feelings about reusing head bolts?

on older subaru's you reuse the head bolts, 99 percent sure the newer EJ models are the same.

 

no gasket dressing neccessary or recommended on the head gaskets.

It's all of the other gaskets that I am questioning.

no dressing needed on any subaru gasket.

 

water pump gasket could use some of that tack sealant and that's all you should need. thermostats too...but i think you will find an o-ring on your thermostat so nothing needed there.

Use sealant on the oil pump, cam caps near the corners where the valve cover gasket will lay, and over the ends of the plastic plugs in the rear of the heads where the valve cover gasket meets the head. Use sparingly.

use sealant sparing ly where metal hits metal, or on sharp corners. The gaskets in the set replace the use of sealant in all other cases. where metal hits metal is the oil seperator (at the rear of the engine, make sure yours is metal. If it is not, replace it with a metal one.), the mating surface of the oil pump, the oil drain pan, and the two halves of the block. Sharp corners are the cam covers around the cam seals, as well as the two plugs at the rear of the cam area (DOHC EJ25). Head bolts can be reused. Be sure to follow the torque sequence. Also, the cam berring caps are torqued to 14Ft-lbs, and the cam seal caps are torqued to 7ft-lbs. Have the heads checked for flatness before they get resurfaced. Most of the time they do not need it. resurfacing them when it is not needed takes away metal that does not need to be taken away, and changes the compression of the cyls without needing to. If the machine shop has to replace or grind any of the valves, make them adjust the clearance on the cams. It is a lot easier for them to do so than it is for you to (it is one of those things that can get very expensive very fast).

I pulled the heads yesterday on my 98 Forester because of the typical head gasket symptoms (engine out of the car) and noticed that all of the gaskets seemed to be assembled dry. I have the overhaul gasket set so what gaskets require dressing and what type? My shop manual doesn't mention it. I'll be taking the heads to a machine shop this week for resurfacing, pressure testing, and installing stem seals. Also, what are the feelings about reusing head bolts?

 

I did the head gaskets in my "99 and I replaced the head bolts. I would be surprised if the '98 was any different. Need to replace.

I think that technically they should be replaced, but I didn't replace the bolts when I did our head gaskets, and that was about 75k miles ago with no troubles, FWIW.

Replaceing head bolts is an argued subject, some people get away with reuseing them and others arent so lucky. They are usually recomended to be replaced when takeing of the head. This is for the main reason of when you torque down the bolts that they stretch. if you reuse the stretched bolts they wont have the right length to be tightend properly which will result in another blown head gasket. So if I were you I would not take the chance of reuseing the old head bolts. I would rather spend some extra cash than to have to spend all that money all over agin to replace the head gaskets.

I did decide to use new head bolts because of the torque/turn method. Got the heads back yesterday so this morning I started putting it back together. On the first head one of the new bolts was so crooked that it rubbed on the inside of the bolt hole as I turned it. I figured that if I was going to reuse one bolt to replace the defective new one I might as well reuse them all and save my $100.

I did decide to use new head bolts because of the torque/turn method. Got the heads back yesterday so this morning I started putting it back together. On the first head one of the new bolts was so crooked that it rubbed on the inside of the bolt hole as I turned it. I figured that if I was going to reuse one bolt to replace the defective new one I might as well reuse them all and save my $100.

 

The threads are weaker then the bolts, so there is no need to replace head bolts. in a iron block with iron heads you replace the bolts, since the bolts do stretch and yeild a bit.In a aluminum engines this is not a worry.

 

nipper