I have a 1999 Honda Civic Ex, 115k miles, that at least appears to have developed motor and trans issues all at once. Approximately 1.5 months/3,000miles ago I had the oil changed. Yesterday after exiting a local highway and turned down the radio I heard what sounded like very loud valve tapping and the car stalled at a traffic light. I was able to restart and limp the car home. I checked the oil and it was 2.5 quarts low (out of 3.8 used). After adding the oil the upper motor chatter quieted, but is still present during acceleration. At the same time the automatic transmission appears to be slipping and not shifting smoothly. The car is not visably burning oil and while there is some wetness on the bottom of the motor where it mounts to the trans, the underside of the car does not appear to have 2.5 quarts of oil showered around. The car has never needed even a half a quart of oil between changes. Any ideas where the oil may have gone or what I should check out? oes the civic use yellow coolant? if so, its not yellow any more.

 

Sounds like a head gasket went. Is the formerly yellow/greenish coolant now resembling chocolate milk?

 

No, just dark. Is there any other way to tell?

 

Yep - open the oil cap on the valve cover, and look inside. The oil there should be more along the lines of having the "chocolate milk" look if it's a blown head gasket. It'll probably be a creamy, tan color.

But even with you describing the coolant as "dark" would indicate to me that it's probably where most of your oil ended up. Odds are, the oil/coolant is mixing via the broken head gasket, as well as leaking into the cylinder and burning off inside the cylinder, thus not creating an external leak.

Additionally, when a head gasket goes, the engine runs very much how you described it in your initial post. I would assume the auto trans is reacting off of the now-lower vacuum pressure caused by the faulty head gasket.

 

Thanks for the info. I check the condition of the oil.