Got a compression test done on my high mileage '96... are these results OK?

Hi, I bought a 96 3.4 4x4 about a year and a haf ago, it's a bit of a beater with 255,000 mi / 413,000 km on it, I thought I'd get a compression test done on it during its last visit to the shop before I put any kind of money into it. Turns out it badly needs the timing belt done, and hell might as well go water pump as well, but the compression results were as follows:

165/135/150/150/180/160

Is that enough of a variation to cause concern, or is that fairly normal for an engine with that high mileage?

 

Straight out of the FSM

Compression pressure:
1,200 kPa (12.2 kgf/cm2, 174 psi) or more
Minimum pressure: 1,000 kPa (10.2 kgf/cm2, 145 psi)
Difference between each cylinder:
100 kPa (1.0 kgf/cm2, 15 psi) or less

I'd say your looking at a rebuild.

 

Those number depend on the competence of the guy performing the test. They are a bit low.

If it's running fine with no misfires I wouldn't sweat it

 

Fix it when it breaks. Drive the Hell out of it. God speed

 

I’d get the timing belt done and redo the compression test. 180 is suspect as well as 135. But, if you are not pressed to do the Belt, like b-r-o said... You can check plugs too. Might be telling.

 

That was exactly my thought when I seen the numbers. That is a big deviation and OP didn’t state there was a current issue. Like you said, a lot of it depends on the guy doing the test. Then you have to factor in the quality of the tool itself. I don’t put a lot of faith in those cheap testers. The fittings and crimps are subpar

 

Yeah the timing belt is critical, I haven't driven it since I took it to the shop, it's going back in for that work on the 26th.
It was driving fine back in the fall, then I went off to Mexico for 3 months, arranged to take it in the day after I got back and when I started it up it REALLY did not want to start and when it did finally, a lot of white smoke. I sure as hell hope that wasn't the head gasket.

 

OP I would consider checking your valve clearances at some point. Some people see significant improvements in compression #'s when the valves clearances get put back into spec. I'd still echo what others said about not sweating these results though.

 

I’d beat the fawk out of it for another 255k.

 

That hard start and white smoke when you got back from Mex is concerning if it's coupled with a slow loss of coolant

And I'd agree, checking valves may be worthwhile. Especially at that mileage

 

Good advice here so far, thanks everyone.

I just checked the coolant level, it's right at the top.

 

I'd suggest photographing that coolant level or maybe even marking it with a sharpie in order to closely watch for any losses in light you observing that white smoke coming out of the exhaust.