mtnbkerman Posted April 9, 2008 Share Posted April 9, 2008 Sorry if this is a repeated question. Looking through the forum, sometimes you don't find exactly what your looking for, as why I am here. I am going to skip all the crap about diagnosing bad head gaskets, as there are plenty of posts to figure that out and it has been done by a professional mechanic anyways. The question is this, I'm going to pull the 2.5L engine out of my 1998 subaru outback this weekend and do a timing belt job and a head gasket job. Was wondering if it is recommended/necessary to get a head job done (resurface/valve job)? This will be my first time doing this so any input or recommendations i get would be of great help. Thanks tons! Link to comment Share on other sites More sharing options...
aircraft engineer Posted April 9, 2008 Share Posted April 9, 2008 aluminum heads - good idea to resurface when you have them out Cheaper than doing it again later Link to comment Share on other sites More sharing options...
nipper Posted April 9, 2008 Share Posted April 9, 2008 Not a good idea, mandatory. Also only use Head Gaskets from subaru. nipper Link to comment Share on other sites More sharing options...
davebugs Posted April 9, 2008 Share Posted April 9, 2008 I have them checked for cracks, resurfaced - and they clean them. If I have the time I usually drop the radiator to have it flushed and pressure tested. Worth the 20 bucks for peace of mind if I'm waiting on parts or anything. Especially if there may have been 'additives' in the cars past. Dave Link to comment Share on other sites More sharing options...
subaru360 Posted April 9, 2008 Share Posted April 9, 2008 I check them for straightness. If they aren't warped, they don't have to be resufaced. Some people just do it anyway, your choice. Link to comment Share on other sites More sharing options...
nipper Posted April 9, 2008 Share Posted April 9, 2008 I check them for straightness. If they aren't warped, they don't have to be resufaced. Some people just do it anyway, your choice. Its highly recomended that the all aluminum engine heads be resurfaced. http://www.aa1car.com/library/gasket_failure.htm Finish is much more important with HG's then it used to be. nipper Link to comment Share on other sites More sharing options...
mtnbkerman Posted April 9, 2008 Author Share Posted April 9, 2008 Thank you guys tons! Would any of you guys recommend a valve job? and any idea how much it runs to get both heads resurfaced? Link to comment Share on other sites More sharing options...
nipper Posted April 9, 2008 Share Posted April 9, 2008 Anytime you have the heads out and its over 100K a valve job is money well spent. Which leads me to ask, why are you replacing the HG? is there an issue? Even if you know its a HG issue, have you done a wet/dry compression test to check the condition of the engine? nipper Link to comment Share on other sites More sharing options...
mtnbkerman Posted April 9, 2008 Author Share Posted April 9, 2008 Have not done a wet/dry compression test. Sorry a noob at all this, could you explain that to me? Replacing the head gaskets, obviously cause they have gone bad or maybe i have been told wrong. Here are the symptoms of my car, maybe you can tell me for sure? Start my car up and let it idle in the drive way and have let it set for at most 25-30 minutes and it never gets over normal running temperature, as soon as I leave the driveway it starts to heat up. Blows cold air, the upper radiator hose is hot after this time, tried replacing the thermostat, added antifreeze thinking maybe I was low. Hope you can tell me its something different! Link to comment Share on other sites More sharing options...
nipper Posted April 9, 2008 Share Posted April 9, 2008 Have not done a wet/dry compression test. Sorry a noob at all this, could you explain that to me? Replacing the head gaskets, obviously cause they have gone bad or maybe i have been told wrong. Here are the symptoms of my car, maybe you can tell me for sure? Start my car up and let it idle in the drive way and have let it set for at most 25-30 minutes and it never gets over normal running temperature, as soon as I leave the driveway it starts to heat up. Blows cold air, the upper radiator hose is hot after this time, tried replacing the thermostat, added antifreeze thinking maybe I was low. Hope you can tell me its something different! Yup HG. How many miles are on it ? Wet Dry compression test will give you an idea of the condition of the engine. A dry test is just that, dry. A wet test is done with oil squirted in the cylinders. If there is ring wear the numbers will go up dramatically. How many miles are on this car? Link to comment Share on other sites More sharing options...
mtnbkerman Posted April 9, 2008 Author Share Posted April 9, 2008 122K miles. Any idea how much a valve job cost? Link to comment Share on other sites More sharing options...
nipper Posted April 9, 2008 Share Posted April 9, 2008 122K miles. Any idea how much a valve job cost? Thats an OK mileage for a engine (meaning pistons and bearings should be fine). Someone else will chime in on the cost, i wont quote a NY price. The first thing you do is get the radiator flushed out. before you do anything else. Old coolant and oil and dirt nakes glue when air hits it. It will clog the radiator, so best to flush that first. nipper Link to comment Share on other sites More sharing options...
idosubaru Posted April 9, 2008 Share Posted April 9, 2008 122K miles. Any idea how much a valve job cost?$100 - $150. it's likely good for another 100k but i'd do it while you're in there. it's very rare that i don't have a valve job done while it's apart. Link to comment Share on other sites More sharing options...
nipper Posted April 9, 2008 Share Posted April 9, 2008 $100 - $150. it's likely good for another 100k but i'd do it while you're in there. it's very rare that i don't have a valve job done while it's apart. Well it is sort of tough to have it done when its all together now isnt it? Silly ................. Link to comment Share on other sites More sharing options...
mtnbkerman Posted April 9, 2008 Author Share Posted April 9, 2008 Sorry, Should I flush it before pulling the engine? Thanks by the way, you have been such a help. Link to comment Share on other sites More sharing options...
nipper Posted April 9, 2008 Share Posted April 9, 2008 Sorry, Should I flush it before pulling the engine? Thanks by the way, you have been such a help. flush it with it off the car, makes less of a mess that way. nipper Link to comment Share on other sites More sharing options...
mtnbkerman Posted April 9, 2008 Author Share Posted April 9, 2008 Cool! Think I got all the info I was looking for. Now just to pulling the engine. FUN! Link to comment Share on other sites More sharing options...
nipper Posted April 9, 2008 Share Posted April 9, 2008 Not to state the obvious, but with the engine out it is a lot easier to change the spark plugs Sort of surprised how many people don't do that. Also look up timing belt replacement here, to get a feeling on what to replace there. nipper Link to comment Share on other sites More sharing options...
aircraft engineer Posted April 9, 2008 Share Posted April 9, 2008 there's another way, too - do a differential compression test It uses a meter and compressed air one of these - http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=94190 They can be a bit tricky to use if you don't know what you are doing. It's not the old "crank it and see what it pumps up to" compression tester. Link to comment Share on other sites More sharing options...
nipper Posted April 9, 2008 Share Posted April 9, 2008 there's another way, too - do a differential compression test It uses a meter and compressed air one of these - http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=94190 They can be a bit tricky to use if you don't know what you are doing. It's not the old "crank it and see what it pumps up to" compression tester. Except not everyone has compressed air (including me). i try to keep it as simple as possible, especially when its someone doing it for the first time. nipper Link to comment Share on other sites More sharing options...
aircraft engineer Posted April 9, 2008 Share Posted April 9, 2008 for a good selection of SUB timing parts stuff try these guys http://www.theimportexperts.com a kit of everything to do the engine front (belt, pulleys, tensioner, waterpump, valve cover gaskets, cam seals - all of it) was about $300 (the tensioner was $89 - if you don't need it you don't have to buy it - they sell lesser kits, even customize to what you need) I have reservations about the Chinese timing belt, so got the German (made in Mexico) belt for $10 extra If you have it out, might as well fix it "right" Link to comment Share on other sites More sharing options...
johnceggleston Posted April 9, 2008 Share Posted April 9, 2008 Not to state the obvious, but with the engine out it is a lot easier to change the spark plugs nipper nipper, this is a good point. considering how difficult it is to reach one of the plugs, it could also be done in conjuntion with the compression test. the plug's already out right? i guess it just depends on the cost of the plugs and if you actually are going to repair the engine. Link to comment Share on other sites More sharing options...
screwbaru2 Posted April 9, 2008 Share Posted April 9, 2008 Do you take out the washer tank and the air induction ducting when doing plugs? If not try it there are no to hard to get to plugs on a 2.5. Link to comment Share on other sites More sharing options...
aircraft engineer Posted April 10, 2008 Share Posted April 10, 2008 on the IMP don't even need to take it "out" - just disconnect the tank (all 2 bolts) and have someone hold it up while you swap the driver rear plug (or valve cover bolt if you are doing the gasket) Link to comment Share on other sites More sharing options...
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