Interpreting the results of a compression test

Maintenance/Repairs
1

I have a 1987 Toyota Pickup. I tested the compression in

the cylinders. I measured 166, 167, 170, 170. The book tells me it should be 171. I didn’t bother to test by squirting oil in the cylinder. I’m no expert but I think these ratings are good enough not to bother doing anything about. What say you experts?



RandomTroll

2

Perfect.

3

Nothing wrong with them for the age and what is assumed to be comparatively high mileage. The 4 PSI spread is perfectly acceptable.

4

Thats better than some new cars…LOL

transman

5

You only do rust tests on a truck that old.

6

The long-time general rule of thumb is that if all cylinders are within 10 p.s.i. of each other, then you’re good to go. I second 'wentwest". Perfect.

7

I think he’s just bragging. I’ll bet the next post is going to be something like “Oh, by the way, there’s 600,000 miles on this engine” or something!

8

Good readings with variation well within limits.

9

Quoth GreasyJack: ‘I think he’s just bragging. I’ll bet the next post is going to be something like “Oh, by the way, there’s 600,000 miles on this engine” or something!’

It was an honest post. The vehicle has less than 150,000 miles on it. Since I moved to town 4 years ago I have put less than 2,000 miles
on it total. I had never checked the compression. The Chilton’s & Haynes tell me what it should be, that differences of 14 psi represent
a problem, but not what to think of smaller differences.

 Quoth pleasedodgevan:  'You only do rust tests on a truck that old.'
 It has very little rust.  I live in the desert and address every sign of rust quickly.

 Thanks for your answers.

RandomTroll