L245DT low compression

   / L245DT low compression #1  

scud

New member
Joined
Nov 13, 2025
Messages
3
Tractor
L245dt
Hi all,

I'm new to these forums, as I only recently started my tractor adventures.

I bought an old L245DT, which i knew needed some love, and have just started to work on it.

Current issue I am working on is that it is relatively hard starting. By that I mean it needs the full 40 second glowplug preheat, quite a bit of cranking before she starts, and that even on warm days.
Beside that, i noticed a bit of blowby from the breather tube.

What i did:
Compression test. All cylinders approx 300psi. Wet test makes negligible to no change.

Blew some low pressure shop air into the glowplug openings and listened. When valves are shut i hear a very slight hissing, but cannot tell from where. No bubbles in the water, loosening the little plug to gauge oil level doesnt seem to change sound either.

Next i did a squish test, and got about 1 to 1.1mm between all cilinders, so i am thinking the head gasket used is too thick.

However, before i dig any deeper, i wanted to check if there is anything else i should look out for, and whether or not i should change the piston rings while i am going to take off the head anyway.
 
   / L245DT low compression #2  
Make sure your air cleaner is clean and the air path through the manifold is clear. I suspect you do need new rings but free breathing is essential.
 
   / L245DT low compression
  • Thread Starter
#3  
Ah yes, good point. Filter is squeaky clean, as is housing and tube.
I did however notice on the intake, that cylinder 1 has quite some soot on the intake, while the others are clean. But im not sure what that means. Bad injector?
 
   / L245DT low compression #4  
If you're taking the head off you may wish to consider a valve job. You may have some blow by. Are your glow plugs all good?
 
   / L245DT low compression
  • Thread Starter
#5  
With a valve job, do you mean lapping the seats? I did set the clearance on them.

Glow plugs are indeed all good, checked those before.
 

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