MIC’S MEMOS

Turbo-diesel own­ers are ad­vised to check their en­gine’s fil­tra­tion sys­tem from in­take noz­zle to man­i­fold, says Mic van Zyl.

Go! Camp & Drive - - Contents -

Ican well imag­ine that some­where in the world, there is cur­rently a short­age of eggs; and they are all to be found against the walls at Toy­ota. Such is this man­u­fac­turer’s rep­u­ta­tion for re­li­a­bil­ity that when some­thing does go wrong, just about ev­ery Toy­ota de­trac­tor and his dog will climb on the “Bash Toy­ota” band­wagon. Those of you who read my pieces in this pub­li­ca­tion may know my feel­ings to­wards Toy­ota ve­hi­cles. I wouldn’t eas­ily buy an­other brand with my own money. I love the Hilux – the looks, the en­gine and gear­box, the un­ques­tioned re­li­a­bil­ity and su­pe­rior re­sale value. How­ever, I dis­like the ride and the low level of lux­u­ries avail­able, and so I drive a Ford Ranger Wildtrak in­stead. It’s a great truck, full of lux­u­ries, with a su­perb ride. The en­gine is gruff and the gear­box feels like it comes from the early 70s, and af­ter three years when it’s time to re­place it, I know I’m not go­ing to get much for it; but it’s a com­pany car, so I’m shrug­ging my shoul­ders. With only 33 000 km on the clock, it’s been back to Ford a cou­ple of times for a failed sen­sor. Hav­ing only driven Toy­otas up to this point, it’s a new ex­pe­ri­ence for me to be vis­it­ing a deal­er­ship work­shop out­side of nor­mal ser­vices. If you’re lis­ten­ing, Ford, the ex­pe­ri­ence there is not great.

I’M AFRAID that this time the Toy­ota abuse is per­haps war­ranted. It would seem that there are a num­ber of Hiluxes, For­tuners and Pra­dos that are hav­ing dust ingress issues around the air fil­ter box. It would ap­pear that the air fil­ter boxes are dis­tort­ing, al­low­ing un­fil­tered air to by­pass the fil­ter and en­ter the en­gine. If the air is clean, there’s no prob­lem. But if you’re trav­el­ling down a dirt road or driv­ing in a dusty convoy, chances are your ve­hi­cle air in­take is suck­ing up a bucket-load of dust. If the air fil­ter doesn’t cap­ture this dust, it goes straight into your en­gine. Sand dust is es­sen­tially small par­ti­cles of sand, made up mostly of some form of sil­ica. It’s a very hard ma­te­rial; and when mixed with oil and fuel fumes, over time this com­bi­na­tion be­comes an abra­sive paste that causes pre­ma­ture en­gine wear, which may even lead to en­gine fail­ure. With diesel-pow­ered 4x4 ve­hi­cles specif­i­cally: be­cause most of these are tur­bocharged, thus ar­guably the most com­mon vic­tims of dust ingress. Turbo im­pellers can spin at up to 250000 rpm. At this speed, it’s been found, these mi­cro­scopic dust par­ti­cles punch mi­cro­scopic holes right through the im­peller blade ma­te­rial. Over time, the blades are worn away, lead­ing to a drop in turbo boost ef­fi­ciency. In ex­treme cases, these worn im­peller blades can cause the im­peller to be­come un­bal­anced, caus­ing im­peller bear­ing wear and fail­ure and lead­ing to cat­a­strophic turbo fail­ure.

IN MANY mod­ern ve­hi­cles, the air in­take tract from air box to in­take man­i­fold con­tains a num­ber of elec­tronic sen­sors that re­lay in­for­ma­tion to the ve­hi­cle’s elec­tronic con­trol unit (ECU), such as air in­take tem­per­a­ture and ve­loc­ity. Should these sen­sors be­come cov­ered in dust, they may pro­vide the ECU with in­cor­rect in­for­ma­tion, re­sult­ing in the ve­hi­cle en­ter­ing limp mode. This is not a gen­eral prob­lem, and doesn’t af­fect ev­ery Toy­ota; in fact, it could af­fect any ve­hi­cle. My ad­vice, es­pe­cially for turbo diesel own­ers, is to check your fil­tra­tion sys­tem from in­take noz­zle to man­i­fold. En­sure that the fil­ter is clean, and that the fil­ter hous­ing is air­tight. En­sure that the air trunk­ing be­tween the air box, in­ter­cooler, turbo and in­take man­i­fold is un­dam­aged and is not leak­ing. A good pre­ven­ta­tive mea­sure for dust in­take is to move the air in­take of your 4x4 from the en­gine bay or dusty wheel arch up to next to the wind­screen, by means of a well­built snorkel. Clean cool air is al­ways way bet­ter than hot, dusty air – even if your air fil­ter is work­ing prop­erly.

...when some­thing does go wrong, just about ev­ery Toy­ota de­trac­tor and his dog will climb on the “Bash Toy­ota” band­wagon.

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