2

I have a 99 Toyota Corolla with 255k miles. According to the service manual, cylinder compression should be 145-218 psi, with no more than 15 psi variation between cylinders. I tested mine and read 30 psi variation before adding oil for a wet test. After adding oil, compression was a bit high. The compression slowly built up after 5-10 engine strokes.

|Cyl.| Dry | Wet |
------------------
| 1  | 190 | 210 |
| 2  | 180 | 210 |
| 3  | 200 | 230 |
| 4  | 210 | 220 |

From what I've read, the slow pressure build-up, plus the higher pressure after adding oil, indicate worn piston rings. As I don't have low compression, I don't see evidence of a bad head gasket.

What do these numbers tell me about the engine condition and/or expected time until rebuild?

Note: The car has been burning oil for a few years, and has smoky exhaust. I assume oil slipping by the piston rings is a contributing factor. Also, oil has been collecting in one of the spark plug wells.

Thanks!

zwiebelspaetzle
  • 147
  • 6

1 Answers1

2

The smoky exhaust is more often due to oil passing by the worn valve seals and guides.

Those readings don’t seem too serious, may cause a slightly rough idle but predicting the further life is just a guessing game.

Solar Mike
  • 34,681
  • 2
  • 30
  • 59