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Old 12-05-2005, 08:14 PM   #1
DemonScooby
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Default Leaky head gaskets or not...

Hey, I've been having problems with my RS overheating, or at least getting hot and me turning it off before it gets too hot, and I figured it was the head gaskets leaking, since it's a notorious problem with the 98 2.5L. I took it to Stephen Jory Subaru and had them check it out, and they say yea, it's the head gaskets. The weird thing is, the engine temp will go down to normal if I turn on the A/C. So I can run my car as hard as I want w/o worrying about it overheating if the A/C is on. Anyone know why this happens? Maybe it's not the head gaskets but a sensor somewhere. Let me know if you know anything. Thanks,

Mike
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Old 12-05-2005, 09:23 PM   #2
kendogg41
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take a look for yourself, crawl under the car, see if you see coolant or oil leaking where the head meets the blocl, and same for the top of the motor. Then check your coolant in the radiatror, make sure there is no oil in it, then check the oil, see if there is coolant in it.
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Old 12-06-2005, 09:32 PM   #3
volvodr66
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First off, I'm not a Subaru Technician, but I am; an ASE Master with L1 Advanced Engine Performance Certification and I am a professional Volvo Expert Technician.

Head gaskets can leak in a number of different ways, most of which are internal. As kendogg41 said, it is possible to have an external leak between the head and the block and a visual inspection is the first step. Also, removing the oil cap and looking for water in the oil, which would show up as a whitish-brown milky looking substance on the reverse side of the cap is good advice. There is also a possibility of oil leaking into the coolant and checking in the coolant overflow for an oily residue floating on the surface is another quick step to take.

Internal leaks can be;
1. Coolant leaking into the oil.
2. Oil leaking into the coolant.
3. Oil or Coolant leaking into the combustion chamber.

I've already discussed the first two. With oil leaking into the combustion chamber you generally will see a bluish looking smoke from the exhaust. With coolant leaking into the combustion chamber you will get a whitish looking smoke.

The overheating can be caused by combustion leaking into the cooling system affecting the proper flow of the coolant. This also increases pressure in the cooling system and generally you will notice that the radiator hoses will be quite hard after driving for a bit. Often when a head gasket has been allowed to leak for some time, we see cars come in with new cooling system components installed due to this increased pressure, such as a leaking radiator, water pump, etc.

The most reliable test for a head gasket leak detects the most common, and that is a combustion leak into the cooling system. We usually drive the car for a few minutes and then remove the radiator overflow tank cap. A special tool that is filled with a blue liquid and has a squeeze bulb on one end is then placed on the opening, and when you squeeze the bulb it draws the air in the cooling system out and bubbles it thru the blue liquid. If combustion is present the liquid will turn light green or yellow indicating a head gasket leak. This test is very reliable in indicating a head gasket leak caused by combustion since there should never be combustion gases present in the cooling system. The only thing is though that if the test is negative, there still could be a head gasket leak thru one of the other ways. Long story short is, if this test is used and indicates a leak, you have one. If it doesn't indicate a leak, you still COULD have one.

I'm not sure exactly how the RS is set up but on most cars the cooling fan will only come on if the engine coolant temperature gets high enough but if the A/C is turned on the fan runs continuously. I would also be sure and have the thermostat checked and make sure that air flow thru the radiator and condenser isn't compromised by bugs, debris, etc. If the radiator or condenser is somewhat clogged externally, it can cause high engine temperature but with the fan running it may be just enough airflow to lower the temperature down to normal.

I would be interested to know what method they used in determining you have a head gasket leak.

Hope this helps. Didn't mean to ramble on so much......
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Old 12-07-2005, 12:01 AM   #4
DemonScooby
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Quote:
Originally Posted by volvodr66
First off, I'm not a Subaru Technician, but I am; an ASE Master with L1 Advanced Engine Performance Certification and I am a professional Volvo Expert Technician.

Head gaskets can leak in a number of different ways, most of which are internal. As kendogg41 said, it is possible to have an external leak between the head and the block and a visual inspection is the first step. Also, removing the oil cap and looking for water in the oil, which would show up as a whitish-brown milky looking substance on the reverse side of the cap is good advice. There is also a possibility of oil leaking into the coolant and checking in the coolant overflow for an oily residue floating on the surface is another quick step to take.

Internal leaks can be;
1. Coolant leaking into the oil.
2. Oil leaking into the coolant.
3. Oil or Coolant leaking into the combustion chamber.

I've already discussed the first two. With oil leaking into the combustion chamber you generally will see a bluish looking smoke from the exhaust. With coolant leaking into the combustion chamber you will get a whitish looking smoke.

The overheating can be caused by combustion leaking into the cooling system affecting the proper flow of the coolant. This also increases pressure in the cooling system and generally you will notice that the radiator hoses will be quite hard after driving for a bit. Often when a head gasket has been allowed to leak for some time, we see cars come in with new cooling system components installed due to this increased pressure, such as a leaking radiator, water pump, etc.

The most reliable test for a head gasket leak detects the most common, and that is a combustion leak into the cooling system. We usually drive the car for a few minutes and then remove the radiator overflow tank cap. A special tool that is filled with a blue liquid and has a squeeze bulb on one end is then placed on the opening, and when you squeeze the bulb it draws the air in the cooling system out and bubbles it thru the blue liquid. If combustion is present the liquid will turn light green or yellow indicating a head gasket leak. This test is very reliable in indicating a head gasket leak caused by combustion since there should never be combustion gases present in the cooling system. The only thing is though that if the test is negative, there still could be a head gasket leak thru one of the other ways. Long story short is, if this test is used and indicates a leak, you have one. If it doesn't indicate a leak, you still COULD have one.

I'm not sure exactly how the RS is set up but on most cars the cooling fan will only come on if the engine coolant temperature gets high enough but if the A/C is turned on the fan runs continuously. I would also be sure and have the thermostat checked and make sure that air flow thru the radiator and condenser isn't compromised by bugs, debris, etc. If the radiator or condenser is somewhat clogged externally, it can cause high engine temperature but with the fan running it may be just enough airflow to lower the temperature down to normal.

I would be interested to know what method they used in determining you have a head gasket leak.

Hope this helps. Didn't mean to ramble on so much......

thanks for the advice. the test the dealership used was the one you described with the blue liquid. it never turned yellow but turned a little green. this only happened when the car was really pushed hard. i've check the fans when the car was overheating and both fans were on. using the heater doesn't stop it from overheating but turning on the a/c will, i don't get it. i also replaced the thermostat and had the radiator completely cleaned out.
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Old 12-07-2005, 03:09 AM   #5
HndaTch627
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if the block tester turns green that is usually the start of a head gasket failure. It could go tommorrow, it could go 12 months down the road. but then again you have a '98 so i'd assume headgaskets regardless.

turning the A/C on cycles the fans on for long periods of time that's why you see your temperature decrease. don't confuse the fact that the headgaskets are leaking with being able to run it hard with the a/c on, you may end up running it out of coolant that way.
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Old 12-07-2005, 03:50 PM   #6
DemonScooby
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don't worry, I don't push the car right now at all because of the problem. i do know that the fans are on when the car is overheating and it doesn't cool down, only if the a/c is on and i rev the engine for about 15 seconds.

thanks for the info
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