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I have a 99 honda civic. The engine started knocking while my boyfriend was driving it. He said it had just started. It was low on oil so i figured it was just overheating. However that didnt fix the problem. I thought misfire but we just replaced all the plug wires and spark plugs. It is still knocking and the check engine light if flashing. A few mechanic friends that i called said my engine is about to blow. Just looking for other answers and to see if thats correct

  • Did you top it up with oil? – Zaid Sep 25 '15 at 14:35
  • Yes i did. It is still knocking and the enigine light is still flashing. It kinda comes and goes tho – Chelsey Sep 25 '15 at 14:55
  • If the engine has fuel knock sensors, these could be getting triggered by the knocking which could be causing the warning light to come on (just a guess). – HandyHowie Sep 25 '15 at 15:02
  • Stop driving it. You're looking at a rebuild vs a replacement and, on a 99 Civic, probably a new car. – 3Dave Sep 25 '15 at 22:43
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It sounds to me like you mechanic friends are correct. From your description, the car was driven too long on low oil and is now suffering the effects. If you have topped the oil off and are still having the knocking sounds, it's more than likely the engine has damaged bearings with a classic rod knock to tell you about it. With a rod knock, it is only a matter of time before the engine self destructs.

Considering your car is a Honda, you should be able to find a decent used engine for a reasonable price. Honda made many Civics. Engines for these should be plentiful and relatively cheap. Maybe you can get one of your mechanic friends to install it for you for cheap. Better yet, trade your boyfriend in on one who has his man card and can do the work for you.

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    If I had more points I'd remove the "(j/K!)" from the post. A girl who trusts the Internet more than her boyfriend needs a new boyfriend. – 3Dave Sep 25 '15 at 22:45
  • @DavidLively - Better? :0) – Pᴀᴜʟsᴛᴇʀ2 Sep 25 '15 at 23:48
  • @Paulster2 HA! Yeah. – 3Dave Sep 26 '15 at 0:36
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If it was low on oil and you have been driving it, then you have probably worn any number of bearings and possibly the cam shaft. The engine could be ready to die. Being low on oil is not generally a cause for overheating. Overheating would generally be caused by being low on coolant (water). If the knocking is a low pitched thud, then it could be coming from the crankshaft/con rod bearings. If it is a higher pitched tapping, then that would likely be the cam shaft. Rather than 'blow', it will probably just get noisier then stop.

  • It wasnt low on coolant just oil. It was overheating slightly that i saw. Im not sure how long he was driving it like that though. And its its more a high pitched tapping i think. And the engine is shaking. So is the car salvagable without having to replace the engine? – Chelsey Sep 25 '15 at 14:15
  • If it is just a worn cam or a damaged valve, it could cause a misfire as you are describing. If that is the case, then it could possibly be repaired, but whether it would be economical is another thing. How much oil did you have to add? – HandyHowie Sep 25 '15 at 14:26
  • about 3 quarts of oil – Chelsey Sep 25 '15 at 14:54
  • It was pretty low then. Not good. As @Paulster2 says, you may be better off getting a replacement engine if the rest of the car is worth keeping. – HandyHowie Sep 25 '15 at 14:59
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    Oil has other jobs besides lubrication. Another of it's main jobs is cooling. It also cleans. Being 3 quarts low on oil, it could have caused the overheating issue very easily. – Pᴀᴜʟsᴛᴇʀ2 Sep 25 '15 at 15:06
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there is another choice: You can locate the bad cylinder and then remove the valve spring, take out the piston rod, wrap a rag around it and hammer it gently on a steel or smooth concrete surface to straiten out the Push Rod a bit for re-use. Change the lifter also (chances are the lifter has pitted underneath). This procedure will smooth out the knock considerably but is not a permanent cure unless you use new parts.

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