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TheWeatherWarrior head gasket thread (documentation) 97 2.5Lauto GT

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****Not 100% this goes in Walk-through section or not****

Status: This thread is a work in progress & NOT complete, all posts/replies at the beginning are still under constant revision.


This is going to be a documentation thread (not necessarily a how-to thread) on my excursion into the realm of doing a head gasket replacement DIY job (and maybe more). I guess you could say a Walk-along more than a Walk-through. For many discussions I'll refer to the Hayes Repair Manual for actual repair procedures. I don't feel the need to repeat how-to steps already in print. But I think what will be valuable is the discussions, uncertainties and more of diagnosing, assessing, planning, executing and then testing & verifying all is correct and maybe even improved (like maybe getting some MPGs back).


So first. Let's link some previous threads on the topic. These are relavant to second generation and 2.5L motors similar to mine.







NASIOC Head Tightening Infomation:

http://forums.nasioc.com/forums/showthread.php?t=1062633 (not 100% sure this is correct for my 2.5L)


Also, some basics about my situation and essential information specific to my DIY job:


Car: 1997 Legacy GT wagon with Automatic Transmission (aka BK)

Engine: 2.5L DOHC EJ25D (not exactly sure what the "D" means) but that is the correct code per the VIN.

Mileage: 107,100+/-



I have only owned the car for 1.5 years and put just 16,000 miles on the motor. Only known modification is a light weight pulley when the timing belt was replaced. Extensive records exist, have not reviewed them at this time.


Symptoms (so far):

MOVED TO POST #2 "Detailed Diagnosis"


Other notes:

--Did get a CEL error on Fri. Dec. 10. CEL was read, code P1502 (which is a Radior Fan something-or-other) and then cleared on Wednesday, and went through Emissions fine and passed.

--Since I've purchased the car, the vehicle has been getting below normal/expected/spec'd gas mileage, averaging around 22 to 23 mpg on the highway (with many Gen 2 LGT wagons still getting 28 to 30 mpg on the highway).

--I did do a radiator flush back in the summer around the time the first dry resevior bottle occured. Also replaced upper radiator hose (for good measure).

--NO fluid has ever leaked from the motor.

--I am generally a calm, easy going driver, but in some chasing I have pushed the motor hard.

--Car is not a daily driver. I mostly use it for a few errands and chasing storms. Chasing days can range from a few hundred miles to 700+ miles per day. I think I've had about 15 of those kind of days this summer

--Car has had extensive use in winter weather conditions and performed find (no overheating) and ran for 30 hours straight (only being turned off during re-fueling) during the Major DC winter storms last year.

--Car went through Hurricane Earl affects this past Sept. in the Outer Banks. Sand blasted by hurricane force winds, but did fine.



Quick Summary by date:

--Dec. 10, 2010 - CEL comes on

--Dec. 15, 2010 - CEL cleared (read to be code P1502), passed Maryland Emissions

--Dec. 17, 2010 - Oil Changed, At WalMart. Economy oil...just so something fresh is there and assess if any milky residue exists (it doesn't)

--Dec. 28, 2010 - Overheated again, see below for details.

--Jan. 15, 2011 - Radiator removed.

--Jan. 19, 2011 - Thermostat replaced, thermostat housing cleaned

--Jan. 20, 2011 - Picked up new Radiator from DPS. Too cold outside to install.

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PHASE I - Detailed diagnosis.





--Hydrocarbon Test

--Cylinder Compression Test

--Radiator (pressure/flow) Test


Symptoms (so far):

--blowing cool air on and off through vents when heat is on.

--temperature gauge rises when idle, lowers once in motion

--smell of antifreeze/coolant (light, not heavy)

--dissappearing coolant in resevior bottle at an increasing rate.

-----First noted dry bottle about five months ago

-----Second dry bottle one month ago

-----Third dry bottle six days ago (Friday, Dec. 10)

-----Fourth dry bottle yesterday (Wed., Dec. 15)

-----boiled over and slightly overheated, suck dry once it cooled down (Tue. Dec. 28)

--there is white smoke from the tailpipe. Does not increase with heavy acceleration

--upper radiator house collapsed under pressure / lack of flow (Dec.28)



--December 17, 2010 - Oil Changed. Just did a quick change (via Walmart cheapo). Verified no milky stuff and fresh (although poor quality) oil is sitting in the motor. Not worried about quality stuff since motor will be taken apart anyway. Prior to leaving the house I did top off the coolant/antifreeze and drove for ~ 7 miles with zero signs of overheating, but smell is still consistent and getting stronger.

--January 15, 2011 - Removed radiator. No obvious damage, but lots of dirt and such. See Photos 1 & 2 attached below.

--January 19, 2011 - Replaced thermostat to verify that the issue is not isolated to that. I will check the old thermostat for proper function as well.



Photo Summary:

1) Radiator (engine side) removed w/ one fan removed

2) Radiator (intake side) removed

3) Old thermostat with thermostat housing removed

4) Old thermostat removed ready to be checked (top)

5) Old thermostat removed ready to be checked (bottom)






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PHASE II - Planning (including parts purchases & tools list)




Tools (bold items are needing to be purchased):

--Compression Gauge

--impact wrench (electric)

--torque wrench

--socket set

--scraper (for removing existing head gasket)

--straight edge and gauge set for measuring head warping (if any)

--drain pan



--Head gaskets kit, HG/intake/exhaust & more (recommendations wanted) - Subarupartsforyou: Link $209+shipping (incl. full kit)

--thermostat (Only buy Subaru OEM, others always fail) - Subarupartsforyou: Link $15+shipping (incl. gasket) (paid $21 at local Subaru Dealer)

--intake gaskets -

--exhaust gaskets - Rallitek: Link @$15 each X 2 = $30+shipping

--radiator - CSF brand (paid $190+tax purchased at DPS Tuning in Gaithersburg, MD)


Other Supplies:

--engine compartment degrease cleaner

--fender/paint protection

--parts mat

--zip lock bags

--blue painters tape

--sharpie pen/marker

--silver pen/marker

--hand cleaner

--shop rags

--ARP Torque Lub (seen on PowerBlockTV)

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Phase III - Work commences, disassemble



Note: This is not a detailed how-to. As mentioned, I prefer to refer folks to the Hayes Repair and Maintenance manual for step-by-step procedures.


Step 1. Prepare the work area.

--clean the engine bay with a degrease material. Makes parts easy to see & avoids dirt in internal parts.

--cover and protect engine bay components and exterior body panels to avoid damage to areas that are not being repairs.

Step 2. Removal of Radiator

1) Soak all bolts and clamps with WD-40 or Liquid Wrench. Many bolts could be seized/rusted and shear off during removal (as has been my experience)

2) Drain all fluids

3) Undo hose (remember some fluid will remain, keep drain pan under engine area to catch this)

4) Lift radiator out


Separate thermostat repair/replace: (added jan. 19 2011)

1) Drain coolant/antifreeze

2) Remove lower radiator hose

3) loosen (carefully) then remove thermostat housing bolts

4) remove thermostat housing (carefully...may need a slight tap to break seal)

5) note position of the thermostat (I used a camera to take a picture) and then remove thermostat (again a slight tap may be needed)

6) place NEW gasket onto NEW thermostat (use OEM genuine thermostat only)

7) place new thermostat making sure the new gasket seats into grove and the position matches the previous position.

8) replace thermostat housing (torquing the bolts to the correct torque pressure little by little, alternating sides. Ref. to Hayes Manual for more)

9) replace lower radiator hose (recommend replacing the hose if more than 24 months old).


Photo Summary:

1) combo shot of the radiator bracket loosened and removed

2) radiator removed, not cleaned

3) lower radiator hose disconnected from thermostat housing (with inset of same spot from reverse angle)

4) old thermostat position

5) new thermostat w/ new gasket

6) new thermostat w/ gasket partially installed

7) new thermostat w/ gasket fully installed

8) cleaning the thermostat housing

9) thermostat port, note the lip where the gasket sits

10) use ONLY OEM parts for the thermostat!!!!











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I'll be working right "alongside you" in the PNW on my own headgasket project: http://legacygt.com/forums/showthread.php/just-purchased-98-lgt-wagon-coolant-positive-hydrocarbons-151027.html


Your car and mine (actually my wife's) are at about the same mileage, ours is at 110K.


Almost done with the leaky sunroof hoo-haw, I should have everything in the cabin put back together and steam-cleaned tomorrow. I'll start on the headgasket project maybe Monday if I decide not to wait until after Christmas.


Good luck with yours!

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  • I Donated
Once again, I do not believe this is a HG issue. From the coolant smell, I am guessing it's the heater core. Have you had someone follow behind you to see if lots of white smoke comes out the tailpipe when you floor it? (Keep in mind that in this weather, you will probably get a bit of condensation no matter what, so a little bit is probably not an issue.)
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^Yeah..been a lot of white smoke from the tail pipe...but more consistent regardless of speed. I do still have a lot to assess. I will to the thermostat and check the radiator for pressure. Will do the hydrocarbon test & I will do a cylinder compression test and more to get a full assessment. I've done a ton of reading on LGT.com and SubaruOutback.com and things seem to certainly point toward HG. I many ways I would prefer to do the HG before going chasing, but it would be nice to avoid the costs.


Regardless of whether it comes sooner or later, the HG will get done, and the thread is and will be an ongoing report/discussion.


Your website is awesome!

Thank you.

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  • 3 weeks later...


Radiator removed today. Been waiting for warmer weather, this was about as good as it's gonna get. I did not spend a whole day at it, and did not get around to replacing the thermostat. I had not planned on replacing the radiator, but the amount of sheared bolts is going to require it now.

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