Question about blow by??

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  #1  
Old 11-25-03, 09:04 AM
kkern
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Question about blow by??

I am trying to sell my 94 Saturn SL2 and someone told me that it has blow by. What is this and what does it mean? How do you fix this problem? Any help that you can give me on this would be great!

Thanks!
 
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  #2  
Old 11-25-03, 09:09 AM
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blowby is...

...a term referring to the gasses that escape the combustion chamber into the crankcase during the compression/power strokes of an engine. it usually means that the engine is very worn or that the piston rings are stuck in their grooves. have someone perform a cylinder leakage test and verify this as the cause of your blowby and go from there.
 
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Old 11-25-03, 09:27 AM
kkern
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If this is the case, how do you fix this? Someone told me that they only way is to put in a new motor.. Is this right?
 
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Old 11-25-03, 09:31 AM
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for a bandaid....since you are selling it try 'RESTORE'


http://midwayautosupply.com/detailed...ription.asp?64



go to a local parts store....they should have it on the shelve. dont try to thicken the oil to reduce blowby. these engines are designed to run on thinner oil. you will fry the top end.
 
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Old 11-25-03, 09:58 AM
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get it...

checked out and go from there. engine overhaul in a can doesn't work...
 
  #6  
Old 11-25-03, 10:04 AM
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I agree with carguy.... but blowby isnt JUST exhaust gases. It is anything that can slip by the piston rings. Usually a tell tale sign is oil coming out of the tailpipe. Ask the person that told you this to explain how he came up with this diagnosis.
I, if you are not, am curious about this. Did he just look at it and deternine that?
Billy
 
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Old 11-25-03, 12:31 PM
kkern
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he took off the oil cap and listened to the noise coming out of the car. There was also a lot of air coming out when the cap was off. I have not noticed any oil coming out of the tailpipe. I was also going to replace the pcv valve to see if this helps.
 
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Old 11-25-03, 01:09 PM
otter_
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blow by

Originally posted by kkern
he took off the oil cap and listened to the noise coming out of the car. There was also a lot of air coming out when the cap was off.
sounds like baloney. Most overhead cam engines blow air/gasses out the oil fill if the cap isn't in place when the engine is running.

Have a mechanic do a compression test. If it's ok and you're not sending blue smoke out the tailpipe, there's no problem.
 
  #9  
Old 11-25-03, 01:54 PM
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One thing I think is your selling it and it is not a safety concern so sell it the way it is.If smoke came out with the oil cap off it has blowby.Repairing blowby is an expense you will not recover when selling the car.
 
  #10  
Old 11-25-03, 02:36 PM
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blowby

Blow by is as said pressure getting past the rings going into the crank case.(worn engine) Get a compression check.
I have seen blowby so bad that the air filter was soaked in oil.
I would not buy a car with a worn engine you might try that restore stuff but it is not really an honest thing to do.
 
  #11  
Old 11-25-03, 03:11 PM
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LOL..... Thats funny...... That is called "the path of least resistance". The crankcase is a sealed system and is under pressure. When you take the cap off you open the system and let the oil, fumes, etc out. As the others stated already. Get it checked out by a competent mechanic. This guy doesnt know what he is talking about.
Billy
 
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Old 11-25-03, 03:56 PM
KurtDixon
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I also detect a little BS here too, i'm not even a mechanic No one can tell blow by by putting their ear to the oil cap opening. I would say, if it does not puff any smoke, does not burn oil then you are just fine. Granted, there "can" be blow by without showing these symptoms.
 
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Old 11-25-03, 04:38 PM
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Let me guess.....this was a potential buyer that gave this diagnosis......
 
  #14  
Old 11-25-03, 07:10 PM
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My thoughts exactly Desi501! Sounds like someone trying to gnaw the price down, make you think your car is junk. Unless smoke comes out the oil fill cap, you can't tell if it has blowby by just removing the cap and feeling the pressures. When you remove the cap, you totally defeat the PCV system and you will have pressure coming out. It's normal. If smoke came out, then there is blowby.
 
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