3B low PSI (1 Viewer)

[Gimme a 60]

I have a 3B with 320,000Km. Runs well, cold starts great.


However I bought a cheap compression tester online, and upon compression testing the engine, I have noticed these results.

1. 200 PSI

2. 200 PSI

3. 200 PSI

4. 200 PSI

I wasn’t expecting all cylinders to be exactly the same. But please note, this was after the engine was sitting for about 2 months with 0 oil in the cylinders. I also was only using the one battery, so the engine wasn’t cranking as fast.


Is this normal? What should my PSI be?

Please find the video below of the engine starting after 6 months- it can’t be 200 PSI- the engine wouldn’t be able to run right? This leads me to believe that something else is wrong.



Is it possible that my compression tester isn’t long enough?

 

[AirheadNut]

Were all the glow plugs removed for the compression test?

I don’t have much trust in cheap diesel compression testers, I got one from Harbor Freight and it won’t give a reading over 300psi. Judging by the photo of your glow plug and tester adapter, it does appear that the compression tester adapter doesn’t screw in deep enough to seat into the bottom of the glow plug hole and make a seal.

And no, I don’t think there’s any way a 3B (or any diesel, really) could start with all cylinders at 200psi. It sounds like a healthy engine to me.

 

[Gimme a 60]

Were all the glow plugs removed for the compression test?

I don’t have much trust in cheap diesel compression testers, I got one from Harbor Freight and it won’t give a reading over 300psi. Judging by the photo of your glow plug and tester adapter, it does appear that the compression tester adapter doesn’t screw in deep enough to seat into the bottom of the glow plug hole and make a seal.

And no, I don’t think there’s any way a 3B (or any diesel, really) could start with all cylinders at 200psi. It sounds like a healthy engine to me.

It comes with more fittings for the glow plugs. New compression testers are $300+.


I will report back if I get a different reading.

All glow plugs are removed.

 

[Gimme a 60]

Got my compression test back, I got 400psi across the board cold.


Is this good?

 

[duncanrm]

400psi is great! Thats very much towards the upper end of the specification. If you dont have much blowby, its not using much oil, and you're not losing coolant then I'd say your 3B is very healthy!

 

[Gimme a 60]

400psi is great! Thats very much towards the upper end of the specification. If you dont have much blowby, its not using much oil, and you're not losing coolant then I'd say your 3B is very healthy!

View attachment 3278022

Woohoo!