Low compression in #4 cylinder

[SiberianPatrol]

Got a report back from a diesel specialist that I'm due for a pump and injector rebuild (kind of expected). But then he also told me that the #4 cylinder had very low compression. He said all cylinders were on the low end, but #4 was even lower. My engine is the RD28Ti in a 99 GU.

Is this something to be concerned about and need to get fixed ASAP? Short of a complete engine rebuild, what could be the source and fix for the compression issue? Is it a valve problem or worse a piston and ring problem?


1999 GU RD28Ti turbo diesel; manual transmission; 33" Khumo mudders; ... more mods on the way ;)

[nissannewby]

Did he do a wet and dry compression test?

[SiberianPatrol]

Did he do a wet and dry compression test?

Not sure exactly. Why is it important wet and dry?


1999 GU RD28Ti turbo diesel; manual transmission; 33" Khumo mudders; ... more mods on the way ;)

[SiberianPatrol]

Can anyone tell me or point me to a resource which give the acceptable compression range for the RD28Ti engine?

[mudski]

Can anyone tell me or point me to a resource which give the acceptable compression range for the RD28Ti engine?

I reckon the info you require would be in the manual thats available here for download bud.

[SiberianPatrol]

I reckon the info you require would be in the manual thats available here for download bud.

Yup. After a bit of digging I found the answer to both questions - the wet vs dry compression testing and the compression range. Took a bit of watching to find my engine in the manuals but finally found it.


1999 GU RD28Ti turbo diesel; manual transmission; 33" Khumo mudders; ... more mods on the way ;)

[SiberianPatrol]

Anyone with any thoughts on a rebuild? Should I bother or just look to replace the engine at this stage?


1999 GU RD28Ti turbo diesel; manual transmission; 33" Khumo mudders; ... more mods on the way ;)

[SiberianPatrol]

6060860609
Ok, mates. Just got the results from the diesel specialist on the compression tests and as you can see, the #4 cylinder is definitely below the low limit of 24.5 bar and the #6 cylinder is borderline on being too low.

Anyone have any suggestions on what to do now? Should I drive it as is for a bit and see how she does, or go ahead with a more in-depth diagnostics and rebuild it need be?

[mudski]

No doubt the car will still run. A new fresh motor will mean it will run better though...

[SiberianPatrol]

No doubt the car will still run. A new fresh motor will mean it will run better though...

No doubt. I'll wait to see what it's like when the fuel pump and injectors are rebuilt. Time and finances may be against me rebuilding it at the moment.


1999 GU RD28Ti turbo diesel; manual transmission; 33" Khumo mudders; ... more mods on the way ;)