4jg2 low compression

[Paulo]

Hi guys,

Yet more problems with me truck .Just had a compression test done cylinder 1to 3 read 400 but numbers 4 is way under at 260. Been told by the diesel mechanic that it could be the exhaust valve blocked.Does this means that i have to get the head , or resetting the tappets might help. Any help will be appreciated guys mechanic did not give a clear answer. cheers

[geeves]

burnt exhaust valve of sticking inlet or loose tappet could do this but the chances are not great. When the engine is running is there lots of fumes at the oil filler cap? Even 400 isnt great.
options are valve problem head problem ring problem or bent con rod due to hydro-locking or as has come up a couple of times severely worn bearings.

[Paulo]

Thanks geeves,

I checked the fumes when engine is running and warm and there appears to be no much fumes coming out my last diesel truck had more fumes (TD42 nissan safari). Car had been starting fine when cold and blows blue smoke for about 30 seconds but the it clears ,however she seems to have no much power or boost , no overheating or lots of black smoke..

[geeves]

Nothing to loose by setting tappets so do that first. You should of tried the squirt of oil in the bad cylinder then a second test. If this caused the compression to go up then rings are the issue
what mileage?

[Paulo]

Engine just done 210 thou ks. I will do the tappets and see what happens, then take it from there .