YD25 Cylinder Head D40 D22 R51 Navara

YD25 Cylinder Head 

 head thumb website
 Watch our YD25 Cylinder Head Video


YD25 Navara Cylinder Head Replacement video

The  YD25 engine especially D40s are common to lose coolant due to broken radiator top tank, heater hose plastic fittings, oil cooler hoses, EGR pipe.  Once the temperature gauge goes into the red zone the cylinder head goes soft and the head casting cannot be repaired. Apart from overheating the engine, the only thing that can damage the head is when the chains snap the YD25 is an interference engine, when the chains snap they bend valves and damage the valve train.

over heat 3 bubble rad  
Temperature Gauge When Permanent Damage Starts Bubbles In Radiator From Exhaust Gas In Coolant System


Nissan has stopped making  Genuine YD25 heads. If you want to replace your cylinder head with a brand new head you have to go aftermarket. We have found that some aftermarket head castings are good however the quality of aftermarket internals cams, shims, buckets, collets, and valves do not match the quality of OEM. The problem with aftermarket camshafts is that they are soft and wear on the lobes. When the lobes are worn it wears them into the shims and buckets.  Another issue with the aftermarket internals is that the valves are made out of cheaper metals and wear.

worn cam lobe  shims  
 Worn Aftermarket Cam Lobe  Damaged Shims From Worn Cam Lobes  


Cylinder Head Exchange

We offer reconditioned heads and brand-new heads. All our heads are fitted with genuine cams or aftermarket cams (Tufftride hardened and crack tested in Brisbane, this makes the cams reliable unlike other aftermarket cams), genuine valves, genuine lifter buckets, genuine springs,  new valve stem seals, shimmed to correct valve clearance. Your head is required as an exchange. We need to recover the Genuine valve train parts.

YD25 cylinder head valve train     yd25 cylinder head reco genuine1     yd25 cylinder head reco genuine2   YD25 cylinder head gaskets
 genuine valve parts
   tapet cover view     block side view
  gaskets included with head



Heads are warranted for a period of 12 months or 20 000 kms whichever comes first. The warranty covers defects in material or manufacturing. No warranty if overheated electrolytes. Do not under any circumstances earth the radiator core as this creates electrolysis.

Recommended Extras
There are 3 common parts that cause the yd25 to lose coolant and overheat.

Radiator top tank: We have seen the header tank hose barb on the side of the radiator cap mount fail as low as 110k km. These failures result in total coolant loss within a few minutes. To check the radiator top tank, remove the cap (when cold) and look and feel for brown blemishes in the cap mount. If in doubt, talk with a radiator specialist about replacing the top tank.

Radiator top tank1

Upgraded heater hose kit: Heater hose plastic fittings and oil cooler hoses. We do an upgraded heater hose kit that includes new oil cooler hoses Click here to go to the upgraded heater hose page 

YD25 D40 R51 upgrade heater oil cooler hose kit


EGR delete pipe kit: Egr pipes are prone to cracking internally in the heat exchanger causing loss of coolant Click here to go to the EGR delete pipe page

EGR delete pipe kit