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2001 2.5RS
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Discussion Starter #1
Hello all RS members. My names Kevin Im a technician and a new member trying to seek some direction. heres the case:

Bought a 2001 2.5 RS for 900$ has 220k. The car was bought with an over heating problem which I just want to Fix to drive.. until i have everything i need to swap my fully build ej23 (bored and stroke) motor in.

So far I have noticed the car seems to maintain a proper temp level at idle..
after about 5 minutes or so of driving it starts to steadily climb. Both the thermostat and radiator have been replaced(by previous owner) I actually replacement the thermostat again just to make sure..seems like the system would not bleed properly and there would be some bubbles when running it without the radiator cap..nothing crazy though... I suspected a faulty water pump.. removed it and found it to be in good condition.. inspected the spark plugs they appear to be good..not completely white and dont smell of coolant.. also the exhaust doesnt smell of coolant either.. after i spent a day in the cold doing this work i noticed a large piece of plastic in my bucket that didnt appear to be there until after i removed the water pump... Maybe this was causing blockage and not allowing the system to bleed properly? Also no visable external leaks in the head gasket area on either side.. Maybe just reassembly will tell? Any input would be appreciated guys!!!! Thanks for reading.
 

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2003 BRP 2.5 RS, 2005 Camo 20K
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82 Posts
Did you fully purge all air bubble out of coolant?
How many miles on headgasket?
What thermostat did you replace with?
How does your coolant look in overflow? Is the level high? is it milky brown? bubbles in coolant?
Any hot spots in radiator?
Did you use that crap Subaru conditioner?
 

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1998 Subaru Impreza 2.5RS
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1,471 Posts
Also is your main fan kicking on properly when you get up to temperature?
 

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2003 BRP 2.5 RS, 2005 Camo 20K
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82 Posts
Also is your main fan kicking on properly when you get up to temperature?
Not a bad idea to check fans. But based on OPs description. Seems like rad fans are working properly. He states idle temp is fine but as he starts to drive, it heats up. This is the opposite case of how fans are supposed to work. Fans kick on at idle high temp and they are off when driving, allowing cool outside air to brush rad fins and cool down water. Doesnt hurt to try though, OP! :thumb:
 

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2001 2.5RS
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Discussion Starter #6
Did you fully purge all air bubble out of coolant?
How many miles on headgasket?
What thermostat did you replace with?
How does your coolant look in overflow? Is the level high? is it milky brown? bubbles in coolant?
Any hot spots in radiator?
Did you use that crap Subaru conditioner?
Head Gasket is unknown.
Thermo stat is from Autoparts International Rated for 177 degrees I believe.
There is some bubbling When trying to bleed it through the radiator cap but none in the overflow
Radiator is Brand New
And no Conditioner.
 

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2003 BRP 2.5 RS, 2005 Camo 20K
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82 Posts
Head Gasket is unknown.
Thermo stat is from Autoparts International Rated for 177 degrees I believe.
There is some bubbling When trying to bleed it through the radiator cap but none in the overflow
Radiator is Brand New
And no Conditioner.

KK. Here is some personal experience info that may help. I bought an Oreilly thermostat to replace OEM. 500 miles, thermo failed to open at rated temp, and started to overheat the engine. took out oreilly thermo and put up next to OEM. MY GOD THE SIZE DIFFERENCE in the wax canister! replaced with OEM and havent had problems for 50k miles.

My coolant was bubbling just before head gasket went out. Temp would rise randomly and coolant would overflow out of bottle. Turns out my headgasket sprung an internal leak between coolant and exhaust passages, causing coolant to overflow, over heat, and or bubble. internal headgasket leak between oil and coolant will make your coolant a milky brown. Waft some exhaust into your face and see what it smells like? Sweet? like coolant? White smoke when driving? Not knowing when HG was last replaced, is a big flag. Espcially with the Phase I IIRC, having thir notorious single ply gasket failure
 

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2001 2.5RS
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Discussion Starter #8
KK. Here is some personal experience info that may help. I bought an Oreilly thermostat to replace OEM. 500 miles, thermo failed to open at rated temp, and started to overheat the engine. took out oreilly thermo and put up next to OEM. MY GOD THE SIZE DIFFERENCE in the wax canister! replaced with OEM and havent had problems for 50k miles.

My coolant was bubbling just before head gasket went out. Temp would rise randomly and coolant would overflow out of bottle. Turns out my headgasket sprung an internal leak between coolant and exhaust passages, causing coolant to overflow, over heat, and or bubble. internal headgasket leak between oil and coolant will make your coolant a milky brown. Waft some exhaust into your face and see what it smells like? Sweet? like coolant? White smoke when driving? Not knowing when HG was last replaced, is a big flag. Espcially with the Phase I IIRC, having thir notorious single ply gasket failure
Hmm..I might take a look and compare oem to new thermo. I have 2 new ones now though and problem persisted with both. I've never been stumped like this and now that everything is apart i cant do a compression test just to see what may turn up..im familiar with the hg problems..i've researched and also Fully built a ej20 motor with oem HGs(big mistake) but...as i said in the above..nothing really is indicating a HG problem.. maybe ill do a cylinder leak down test after I get some warm weather and am able to put everything back together. the bubbles that were coming up were rather large? every couple seconds... The plan is to install my built motor into this car. If it needs HG's ill prob sell the motor. Coolant stays nice and green.
 

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2003 BRP 2.5 RS, 2005 Camo 20K
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Hmm..I might take a look and compare oem to new thermo. I have 2 new ones now though and problem persisted with both. I've never been stumped like this and now that everything is apart i cant do a compression test just to see what may turn up..im familiar with the hg problems..i've researched and also Fully built a ej20 motor with oem HGs(big mistake) but...as i said in the above..nothing really is indicating a HG problem.. maybe ill do a cylinder leak down test after I get some warm weather and am able to put everything back together. the bubbles that were coming up were rather large? every couple seconds... The plan is to install my built motor into this car. If it needs HG's ill prob sell the motor. Coolant stays nice and green.
ya. at this point, i wanna say the culprit COULD be thermo or HG. coolant can be nice and green, but can still bubble, indicating water is way too hot. exhaust gases mixing with hot coolant will cause it to bubble. have u block tested it? to see if there is any ex gas in coolant? thats a good next step
 

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2001 2.5RS
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Discussion Starter #10
ya. at this point, i wanna say the culprit COULD be thermo or HG. coolant can be nice and green, but can still bubble, indicating water is way too hot. exhaust gases mixing with hot coolant will cause it to bubble. have u block tested it? to see if there is any ex gas in coolant? thats a good next step
I haven't heard the term "block tested" before. Coolant system pressure test?
 

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2000 2.5 RS-T srp sedan
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put the sniffer on the rad cap and see if its leaking gases.

Mine wasn't bubbling or milky oil, put the sniffer on the rad and sure enough HG failed, causing overheating
 

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2001 2.5RS
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Discussion Starter #12
put the sniffer on the rad cap and see if its leaking gases.

Mine wasn't bubbling or milky oil, put the sniffer on the rad and sure enough HG failed, causing overheating
Well, I watched a video and it mentioned whiteish/green color on the spark plugs which i did have on 1.. But though i was seeing things. I might just pull the heads with the motor in the car. 220k They should be replaced anyway. I just dont want to take them to a shop to tell me that the notorious valve seat cracks are there and i need new heads..
 

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2003 BRP 2.5 RS, 2005 Camo 20K
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Well, I watched a video and it mentioned whiteish/green color on the spark plugs which i did have on 1.. But though i was seeing things. I might just pull the heads with the motor in the car. 220k They should be replaced anyway. I just dont want to take them to a shop to tell me that the notorious valve seat cracks are there and i need new heads..
block tested tests your coolant for trace of exhaust gases. ITs a simple chemistry type sample. pull some coolant, add solutin, if turned green IIRC there is exhaust present in coolant, meaning HG is leaking internally. I highly doubt you will have cracked heads at spark plug threads. I havent seen em as much on 251's as much as 205's, 207's and 257s. I have 280k on my original heads. for a better peace of mind, i had shop pressure test heads. I expect my newly rebuilt motor to run at least another 150,000 miles :)
 

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2001 2.5RS
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Discussion Starter #14
block tested tests your coolant for trace of exhaust gases. ITs a simple chemistry type sample. pull some coolant, add solutin, if turned green IIRC there is exhaust present in coolant, meaning HG is leaking externally. I highly doubt you will have cracked heads at spark plug threads. I havent seen em as much on 251's as much as 205's, 207's and 257s. I have 280k on my original heads. for a better peace of mind, i had shop pressure test heads. I expect my newly rebuilt motor to run at least another 150,000 miles :)
Found a decent size hg failure. Heads look new for the most part. Gonna order the fel pro kits for hg, bolts and timing belt kit. Dropped the heads at the shop 20min after removal
 

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Found a decent size hg failure. Heads look new for the most part. Gonna order the fel pro kits for hg, bolts and timing belt kit. Dropped the heads at the shop 20min after removal
Oh noes! At least you caught it! most people dont. Like me. I learned the hard way for no good reason at all. My coolant was bubbling, shooting out of overflow and i kept on babying it, adding coolant everyday. I should have just done what you did and pull the heads before the engine REALLY overheats. With the leak looking like its between exhaust and coolant passages, i would or have a shop look at the exhaust valves for any discoloration and or pitting caused by coolant. That and if a P0420 comes up, dont be too surprised. just to give you a heads up if the leak is indeed between ex and cool ports. Glad you worked it out! :banana:

and ya, deff go with felpro or the OEM upgraded MLS gaskets. :)
 

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03 Outback Sport White
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i had been experiencing everything you guys posted here with my wife's 03 outback sport. i got a code p0420, then started noticing temp rising, then had several small overheating, with the exact symptoms you guys posted. i just pulled the motor yesterday and there it was, internal leak between the coolant and combustion chamber. seems like the previous owner did a quickie gasket job and sold the car. cheap aftermarket head gaskets AND the head bolts weren't torque correctly. my brother is a mechanic and he just laughed at me while helping me take the heads off. i just wanted some confirmation and i guess i found it. btw BostonMassMurder, how is your car now?
 
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