Diesel parts & ser­vice

Motor Equipment News - - CONTENTS -

One of the most im­por­tant mes­sages that comes across from our read­ers is false econ­omy, or more to the point, tak­ing short­cuts dur­ing rou­tine ser­vices that lead to false econ­omy.

This is par­tic­u­larly im­por­tant when ser­vic­ing diesel ve­hi­cles.

A simple ex­am­ple of this is not chang­ing air, oil and fuel fil­ters dur­ing a rou­tine ser­vice. This might ap­pear to the cus­tomer to be a waste of time, sav­ing a few dol­lars, but the re­al­ity is that dirty air fil­ters can ad­versely af­fect fuel econ­omy, dirty oil fil­ters can lead to in­creased wear in the en­gine, and dirty fuel fil­ters can cause re­li­a­bil­ity is­sues and even lead to road­side break­downs.

The best way to get around these is­sues is for the ser­vice re­cep­tion­ist to prop­erly ex­plain why these fil­ters should be changed, and at the same time why it is im­por­tant to keep rou­tine ser­vices up-to-date, as fil­ters left in “over time” can cre­ate prob­lems.

Another is­sue with diesel en­gines is the po­ten­tial for car­bon build-up around the in­jec­tors.

Tech­ni­cians should check for any com­pres­sion leaks around the in­jec­tors each time a ve­hi­cle comes in for ser­vice as fail­ure to do this can re­sult in costly repairs down the track. This is be­cause if car­bon is al­lowed to build up, the cooling of the in­jec­tor can be com­pro­mised, as well as ponet­ntial dam­age to the in­jec­tor by the car­bon build-up when it has to be re­moved.

How­ever, if an in­jec­tor is dam­aged, don’t just throw it away, be­cause in many cases they can be re­paired.

Another area of­ten over­looked is build-up of car­bon in the in­let tract in some en­gines.

This can hap­pen at mileages as low as 30,000km, and has been noted in some en­gines even when the EGR valve has tested OK. Lots of slow run­ning is the usual cause, and this will of­ten re­sult in an en­gine fault code be­ing trig­gered.

Once this hap­pens it will be nec­es­sary to dis­man­tle and re­move the in­let tract, EGR valve, and man­u­ally clean the sys­tem. The best method would de­pend on the length of time taken for the build-up to oc­cur and the en­gine op­er­at­ing tem­per­a­ture. Soak­ing in acid bath and/or man­u­ally chip­ping or sand­blast­ing ap­pear to be the pre­ferred meth­ods. Pol­ish­ing the area may re­duce the ten­dency for build-up to oc­cur.

How­ever, there are in­di­ca­tions that this can be pre­vented by the reg­u­lar use of good fuel ad­di­tives – Flash­lube’s Com­mon Rail Diesel Con­di­tioner comes to mind.

As well as be­ing a sulphur re­place­ment to lu­bri­cate the ex­tremely high pres­sure pump, this prod­uct is prov­ing very suc­cess­ful in main­tain­ing the in­take man­i­fold air­ways due to cleaner ex­haust emis­sions through the EGR.

Fi­nally, when it comes to get­ting more power and econ­omy, many cus­tomers try to achieve this cheaply by the use of chang­ing ECU chips or us­ing piggy-back chips.

While these can be ef­fec­tive, it is im­por­tant to en­sure that the elec­tronic up­grade with change the du­ra­tion of the in­jec­tion cy­cle rather than just rais­ing the fuel pres­sure as many af­ter­mar­ket kits do.

Rais­ing fuel pres­sure alone can in the long term be detri­men­tal to the in­jec­tors, as too much fuel pres­sure can cause fuel leaks.

How­ever, this won’t oc­cur if the mods en­tail chang­ing the elec­tronic cy­cle; you’l just getb bet­ter power and econ­omy.

These are just a few of the ba­sics diesel me­chan­ics should look at when ser­vic­ing a ve­hi­cle. How­ever, we came across this re­ally in­ter­est­ing Face­book pub­lic group “Diesel Me­chan­ics Tips and Tricks” which seems a use­ful ref­er­ence, par­tic­u­larly when trou­ble-shoot­ing.

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