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09-06-2016, 02:22 PM | #1 |
Scooby Newbie
Member#: 375902
Join Date: Dec 2013
Location: Ontario, Canada
Vehicle:2004 WRXSTi Silver |
going for HG job, need advice..
Bought the car two years ago with small (and persistent ingress of oil into coolant- many coolant flashes) compression, leakdown tests and sniff test came up negative. Put over 10kkm on it without much problems, but she was oil hungry (leaks from under rocker covers & symptoms of compromise valve seals) and was loosing coolant as well.
Eventually lower radiator hose broke (could have been an effect or a root cause) and it overheated (overheating become apparent-on the gauge, only after after I stop the car). Now it displays the HG symptoms: coolant pressure rises up to 20psi, sniff test positive and overheating. I have an appointment next week for HG +TB, valve seals, cover seals etc. job. It is to be divided into three stages: 1st -compression & leakdown test - to determine possible ringlands problem; and here is my 1st question, with a blown HG obviously both test on some cylinders would show diminished reading, is there a way to differentiate the cause for it?; 2nd - ($700) take the engine out, heads off to have look at the cylinders if there is some visible damage and make a decision if to go ahead with HGs and the rest (3rd stage); but what kind of a test can be done at this point to determine that the block is OK? I don't want to dish out >$3k to find out that I have a major problem. What relevant questions to ask a mechanic at this point? , they are specializing in Subarus and are of good reputation. Did a clutch job for me.
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Last edited by kazo; 09-08-2016 at 10:01 AM. |
09-08-2016, 10:02 AM | #2 |
Scooby Newbie
Member#: 375902
Join Date: Dec 2013
Location: Ontario, Canada
Vehicle:2004 WRXSTi Silver |
150 hits and no word of wisdom?, where are you Gurus?
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09-08-2016, 12:03 PM | #3 |
Scooby Guru
Member#: 21145
Join Date: Jul 2002
Chapter/Region:
NESIC
Location: Not in my own time
Vehicle:2002 Enemy of Aku |
I've never had to worry about head gaskets, but from what I have read, it will cost ~$2500 for the Dealer to replace head gaskets. There have been numerous threads on it. Price will vary depending on your area and who does the work.
I *think* other than disassembling the motor and having the block magnafluxed, there is no way to tell for sure if the block is 100%. That does not mean it is not, but magnafluxing will help find cracks in the block that one would not normally see with the naked eye Better question to ask yourself, " Do you trust these mechanics? " If you do, just ask them what you are asking here: - Is the block OK? - What do I need to worry about? - If this was your motor, how would you proceed? - How much is this going to cost me? Don't dive into having the work @your scheduled appointment done until you have the above answers. Having the heads refreshed, and having a weak motor, can cause more problems than you have now since refreshing the heads will increase chamber pressures due to the better valve seals, etc. Depending on what their answers are, you may find it more appropriate to buy a pre-built short block from one of the Vendors here. IAG gets a LOT of positive responses. |
09-08-2016, 12:51 PM | #4 | |||
Scooby Specialist
Member#: 375462
Join Date: Dec 2013
Chapter/Region:
NWIC
Location: Portland, OR
Vehicle:2006 Impreza WRX STI WR Blue |
This is the biggest indicator of HG failure when you have no external coolant leaks.
And now it is confirmed. Quote:
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Aluminum blocks/heads need to be like glass to seal - omit this step or allow the mechanic to be a little lazy here and you'll have another HG job to do in 15k miles. Now - onto the concern about the block: A cylinder wall inspection and pulling the pistons out for a visual inspection of the ring lands is likely the best thing to do - beyond this, you're getting into fairly rare problems. Most block issues will be very prominent in a visual sense - any bearing issues would have shown up long before you started pushing coolant from a HG failure. Personally, I would try to avoid splitting the case halves if you don't need to (I do not know if this is possible with surfacing machine work). While I would replace the valve cover gaskets while the heads are off, valve stem seams can be a bigger job, but I'm assuming you just mean removing and replacing the seals themselves - no valve guide replacement. Last edited by mrsaturn7085; 09-08-2016 at 12:57 PM. |
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09-08-2016, 02:43 PM | #5 | |
Scooby Specialist
Member#: 333468
Join Date: Sep 2012
Chapter/Region:
RMIC
Location: SLC, UT
Vehicle:93 SS - 06 OB XT 03 WRB GD 205/22T 20G-XT |
Quote:
Also, once the heads are torqued back down to the block, check your valve lash and make sure that the clearances are in spec. |
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09-08-2016, 03:34 PM | #6 |
Scooby Specialist
Member#: 375462
Join Date: Dec 2013
Chapter/Region:
NWIC
Location: Portland, OR
Vehicle:2006 Impreza WRX STI WR Blue |
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09-08-2016, 10:08 PM | #7 |
Scooby Newbie
Member#: 375902
Join Date: Dec 2013
Location: Ontario, Canada
Vehicle:2004 WRXSTi Silver |
here you go guys!, thanks
That's thoughts to chew on.. |
09-08-2016, 10:47 PM | #8 | |
Scooby Newbie
Member#: 375902
Join Date: Dec 2013
Location: Ontario, Canada
Vehicle:2004 WRXSTi Silver |
Quote:
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09-08-2016, 11:22 PM | #9 | |
Scooby Specialist
Member#: 333468
Join Date: Sep 2012
Chapter/Region:
RMIC
Location: SLC, UT
Vehicle:93 SS - 06 OB XT 03 WRB GD 205/22T 20G-XT |
Quote:
However, you don't need a fancy wrist pin tool to remove the wrist pins. All you need is a smooth 1/4 rod that is a little bit longer than the block (measuring from the crank snout to the back of the block). All you have to do is: Remove the four wrist pin access covers. There are two on the front, and two on the back. Using a socket wrench or breaker bar spin the crank until you see a wrist pin and align it with the access hole. Carefully remove the wrist pin circlip with a long pair of needle nose pliers or circlip remover. Thread the rod in from the opposite side of the block and smack the end of the rod with a hammer and pop out the pin. Turn the crank until the piston is at least half way up the bore. Spin the piston about a 1/4 turn or so (you can use your hands, or I have used the wooden end of a hammer to tap it into the valve reliefs to get it to move). Then spin the crank around and since the piston has changed position the rod will now pop the piston out of the block. Repeat for the other 3 pistons. You'll have to play around with it for a few minutes until it makes sense/works. It's pretty fun. But now since your pistons are out, might as well split the block and replace the bearings. |
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09-10-2016, 09:46 PM | #10 |
Scooby Newbie
Member#: 375902
Join Date: Dec 2013
Location: Ontario, Canada
Vehicle:2004 WRXSTi Silver |
OK, I have arrived at a momentous decision of doing the job myself.
Being a serviceman most of my life (industrial electronics, automation etc.) and quite passionate about fixing stuff, I'm more excited then nervous. I'm fairly competent with wrenches and having forums like this as a backdrop, plus access to literature, write-ups of hands-on practical experiences of hundreds dedicated professionals and amateurs, plus YouTube I'm positive I can succeed. Moreover my DIY experience is, that although I may spend 3 X as much time as a trader of building/repairing something, I usually do a better job. So I'm completing the list of tools I would need, that is already exciting in itself (a man can never have enough tools )and reading voraciously on the topic. Wish me luck and be patient with some silly questions coming your way. |
09-11-2016, 11:14 AM | #11 |
Scooby Newbie
Member#: 437259
Join Date: Jan 2016
Chapter/Region:
NWIC
Location: Seattle WA
Vehicle:2007 wrx |
Good luck. You'll be fine. Lot of videos on Web to help you through this job. One think that will help when pulling engine is put your jack from the trunk under the tray and lift the tray and engine until the engine mount bolts clear the frame. Then remove the engine. Leave the jack there. No reason to move it until after the engine is back in.
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09-11-2016, 11:39 AM | #12 |
Scooby Newbie
Member#: 437259
Join Date: Jan 2016
Chapter/Region:
NWIC
Location: Seattle WA
Vehicle:2007 wrx |
I also like using an impact gun for disassembling. Some bolt will brake of in the block and the machine shop has to fix those. The impact gun help reduce the chance of bolt snapping off. The ones I had the hardest time with were the 4 small bolts holding the coolant cross over tube. Also the engine mount bolts.
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09-11-2016, 11:59 AM | #13 |
Scooby Specialist
Member#: 419354
Join Date: Apr 2015
Chapter/Region:
MAIC
Location: Newark, Delaware
Vehicle:2007 STI Crystal gray metallic |
going for HG job, need advice..
The threaded rod for the battery tie down is perfect for threading into the clutch pivot pin to pull it out
I def agree on those crossover bolts... 2 snapped on me and were a real b1tch to remove |
09-11-2016, 03:58 PM | #14 |
Scooby Specialist
Member#: 375462
Join Date: Dec 2013
Chapter/Region:
NWIC
Location: Portland, OR
Vehicle:2006 Impreza WRX STI WR Blue |
Just don't forget to find a reputable machine shop that can give you the surfacing specifications you require...
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09-12-2016, 06:46 PM | #15 |
Scooby Newbie
Member#: 375902
Join Date: Dec 2013
Location: Ontario, Canada
Vehicle:2004 WRXSTi Silver |
no going back; bought engine stand and a lift today, and cleaning the garage; looking at Company23 tools and trying to figure out what I really need, plus some metrology tools..
Read some threads in Built Motor Discussion, and one, Talk me out of swapping pistons on my own`maybe slightly discouraging for the faint of heart Shopping for a machine shop as well. |
09-12-2016, 10:38 PM | #16 |
Scooby Newbie
Member#: 374923
Join Date: Nov 2013
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Excited to see how this goes!
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09-12-2016, 11:00 PM | #17 | ||
Scooby Specialist
Member#: 333468
Join Date: Sep 2012
Chapter/Region:
RMIC
Location: SLC, UT
Vehicle:93 SS - 06 OB XT 03 WRB GD 205/22T 20G-XT |
Quote:
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You don't need any bore mics or fancy measuring tools to do this job yourself. Just a set of feeler gauges for setting the ring gaps on the piston rings. You will need a piston ring grinder though. If you have a good machine shop they can measure the bores and let you know how out of round they may be and what size piston you would need. Do not just drop in a new set of pistons without having the block bored and honed. It's best to get the block bored with a torque plate attached if possible. Most non-subaru machine shops won't have one so you would have to purchase and provide one. Have the shop measure the crank and see if it is in spec. A light crank polish won't hurt anything. Then you can get a set of bearings and use plastigauge to see if you need to mix and match standard and oversize sets. Or you can have the machine shop torque the block halves together with the bearings in place and measure the distances, and use the crank measurements to figure out exactly what size bearings you will need. Generally if your crank is in spec then you can probably get away with a standard size OEM bearing and plastigauge to check. I'll probably get flamed for mentioning plastigauge but it can be a useful tool. It doesn't seem like you are going for an all out race build. Keep in mind that the cost of replacing the pistons, machine work, bearings, etc., can add up quickly and start to approach or exceed the price of getting a professionally built short block. |
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09-13-2016, 11:46 AM | #18 | |
Scooby Newbie
Member#: 375902
Join Date: Dec 2013
Location: Ontario, Canada
Vehicle:2004 WRXSTi Silver |
Quote:
1st - let's say I find undamaged pistons, smooth bores within specs, but given the low compression ## (see below) is it a practical approach to just slap a set of new rings? - or is it only a theoretical speculation? Car has only 105kkm, but definitely was hard driven: the 3nd stage Exedy clutch was worn down to the bone.. 2nd - after doing compression & leakdown tests I see a bad result on one, #4, it was the lowest last time (when I bought the car) I measured =130psi, the rest wasn't impressive either ~140,145, leakdown results were good <4% across the board. So I open up the engine and pull out the pistons & find that the block bores are within the specs but piston(s) are compromised - i.e. broken ring land. So can I just replace the pistons with OEM, new rings and be done?, or in practical terms when ring landing is broken does that automatically implies a damaged block and impending rebuilt? or again this is a impractical speculation? I don't want to build a race car, although all the mods on it probably were intended for it, but I don't want to compromise: -APS DR725 FMIC; -ASP TSR70 Inverted Turbo; -APS CAI; -ASP Higth Volume Dual Vent BOV; -PERRIN Fuel Rails & Lines with Aeromotive A1000-6 Regulator; -DENSO 2450 (850cc) injectors -GARRET Turbo Actuator; -BLITZ SBC i-Color Boost S --DC SPORTS UEL headers; -GREDDY muffler; -Front mount Oil Cooler (brand unknown); -Unorthodox Racing Uderdrive Pulleys; -it's ECUTek tuned; -3st BULLY Clutch – recently installed your thoughts? Thanks |
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03-23-2018, 01:46 PM | #19 | ||
Scooby Newbie
Member#: 375902
Join Date: Dec 2013
Location: Ontario, Canada
Vehicle:2004 WRXSTi Silver |
as I hate threads disappearing into the sunset here is a follow up:
due to time constrains I decided to take it to the shop that I used on previous occasions (specializing in Subarus) Happened to be all 9yards: block (pistons & rings but rods, bearings and crankshaft were ok), heads, TB, valve seals etc. etc. Engine back in the car waiting for basic map tuneup to start braking it in. Will end up with > $10.000CND I pretty much trust the guys, but when all was about to be done I hear from them, that Quote:
to which I replied: Quote:
Can you share you collective wisdom on this? |
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04-16-2018, 12:49 PM | #20 |
Scooby Newbie
Member#: 479130
Join Date: Dec 2017
Location: NorCal
Vehicle:2007 Subaru WRX STI Grey |
At the risk of a diverting this thread I would like to ask the following as a new Subie STI owner... similar and related to the subject of this thread...
Recently purchased 07 Hawkeye STI - 75 k miles, really great condition Socal car... looks like prior owner just commuted with the car mostly. Has done needed services on time based on service records. Took car in to a well reputed local indie for a power steering pump replacement... while there the shop said they tested for CO2 in the coolant and saw 27 ppm (hopefully units are right)... thus they said this is evidence the car had been overheated in the past and will need a 'top end rebuild' with new head gaskets to replaced the currently 'breached' ones. Quoted $8,000 to do this engine out service along with 'other things to do while the engine is out' such as new radiator and clutch. Does this sound right? I have driven the car about 1000 miles including a 450 mile highway trip - albeit in not super hot weather... there have been NO signs of overheating and the engine seems completely normal. This is just a weekend car... will at most do a mild Cobb Stage 1 tune, no more than that. Also, if the shop is correct, will I further damage the engine if I do not do this major repair for a little while or a long while? Thanks for any advice or insights from experienced members here. |
04-16-2018, 03:39 PM | #21 |
Scooby Newbie
Member#: 350291
Join Date: Mar 2013
Location: Chicago
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So you just had issues with power steering and no other symptoms/problems and the shop just randomly did a CO2 test and said you need $8k in work? I don't deal with mechanics, but that would throw up a red flag for me. Get a second opinion if you really feel there might be a problem.
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04-16-2018, 04:33 PM | #22 | |
NASIOC Supporter
Member#: 30669
Join Date: Dec 2002
Chapter/Region:
Tri-State
Location: USA, North NJ, 07456
Vehicle:1998 Legacy 2.5GT Silver Sleeper BK, 5MT |
Quote:
Checking it when the engine is hot may show a 1-2" rise in the overflow bottle. Adding a bit of coolant once a year is fine, a quart a month warrants looking further. |
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04-16-2018, 04:56 PM | #23 | |
Scooby Newbie
Member#: 203132
Join Date: Feb 2009
Location: Denver, CO
Vehicle:2005 LGT 5MT Stg2 |
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04-16-2018, 08:15 PM | #24 | ||
Scooby Newbie
Member#: 479130
Join Date: Dec 2017
Location: NorCal
Vehicle:2007 Subaru WRX STI Grey |
Quote:
Quote:
I am new to Subaru but been a car guy forever... dealt with a lotta indie shops... yes, while this shop seems to have a very good reputation this did seem to raise a red flag for me... |
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04-16-2018, 08:49 PM | #25 | |
Scooby Newbie
Member#: 479130
Join Date: Dec 2017
Location: NorCal
Vehicle:2007 Subaru WRX STI Grey |
Quote:
Question -- so if there is a head gasket problem the coolant level in the overflow tank will RISE once the engine has been exercised? or FALL? Of course with heating the coolant will expand which will show some add'l volume into overflow... but I am confused on this... I thought with a head gasket problem car will show a LOSS of coolant, yes? (meaning that coolant will get into the combustion chamber and go out the exhaust with the spent exhaust gases, yes?) Once again, sorry for the noob question... just trying to come up the learning curve. |
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