Engine breather diaphragm 320/07633 JCB Dieselmax, aftermarket

For the JCB Dieselmax 444 engine: engine breather diaphragm 320/07633, an aftermarket part. The card also lists K7137.

Heat and oil vapour make the diaphragm lose its flexibility over time. Vapour escaping at the dipstick tube or the dipstick being pushed out shows high crankcase pressure; check the breather valve and diaphragm first. Replacing the diaphragm is a short job that needs no engine strip-down. High crankcase pressure can also point to ring wear; if the symptoms remain after the diaphragm is changed, measure the compression. The diaphragm sits under the breather valve cover. The diaphragm balances intake vacuum against crankcase pressure while the engine runs. Excess crankcase pressure can also force oil past the turbo seals. The diaphragm is rubber and is in constant contact with oil vapour.

Specifications

Compatibility

The part is listed for JCB 3CX and 4CX backhoe loaders. The catalogue also has the genuine version of this part. Other parts are in JCB Dieselmax engine.

Fitting

Remove the valve cover, take out the old diaphragm and clean the seat. Lay the new diaphragm with its edge fully in the groove and tighten the cover evenly.