Dear Doc,
Last November, my wife’s Yaris 1.4 D-4D started to emit rather more black smoke than one would consider normal, as a consequence we booked it into the local Toyota dealer. The diagnosis was that it required an EGR system clean, at a cost of £300, plus a good run to get the engine hot enough to help the (DPF) regeneration. This we did, after adding some Millers to a low tank of fuel. We did not have the EGR valve cleaned by the dealership though, the charge for the diagnosis being about £58, back in November 2014. On the 9th January 2015, we received a recall notice regarding a potential issue with the Yaris intake system and ECU. In the statement, they say “through our continuous assessment and quality monitoring we have found that, due to insufficient air flow efficiency in the intake system, oil may accumulate in the intercooler and, under certain driving conditions, the oil may flow into the the combustion chamber and might cause engine damage, which may increase the risk of fire in the engine compartment.” They state they will contact us in the near future – presumably regarding some appropriate action. Am I right in thinking that any excessive oil in the intake area could contaminate the EGR valve? Am I also right in thinking that, in these circumstances, the EGR should be replaced, and should I ask for a refund of my inspection fee? Have you or any of your colleagues heard anything regarding this D-4D engine fault? Thanks,
William Hill, Stockport

Hello Bill. Can I put £15 each way on “Millers Miles” in the 3.00 at Lingfield Park tomorrow?
Sorry! Very strange – this intercooler recall is not (yet) showing on the UK VOSA register. There is something pretty similar that I found on the web, with much the same wording, that was published regarding a whole range of Toyotas with such intercooler problems, but it was not listed as a UK recall. I think that you should return to the dealer and report the previous happenings. As you point out, accumulation of oil in the intercooler could result in oil being ingested and then fouling up the EGR. Actually the EGR cleaning job is not lengthy, or that difficult on the Yaris D-4D, so any decent dealer should do this as a matter of course, when handling the recall. You should point this out to them! Having said that, some EGR problems with the D-4D engine have been reported over the years and, like all EGR problems, they will be avoided, or minimised by a number of actions. Regular runs of ten miles plus, giving the engine some decent work to “blow out the cobwebs” as one might, use of “better quality” fuels with a generous detergent additive package – some suspicions still linger about supermarket fuel additive levels, and/or regular use of something like Millers – maybe a “double dose” occasionally.

I found this funny little story on the web, by the way, relating to similar problems with a Yaris D-4D: “After three attempts at sorting this problem out, along with servicing the car, I suggested to the chief technician that it could be that the EGR valve needed cleaning out. He looked at me rather surprised (I am a lady of “a certain age” who he probably thought would not know about these things), but took the car in again and also promised to put on a new vacuum pump – “because they sometimes go wrong.” When I picked it up, he said that the EGR valve was totally clogged up with carbon. He suggested that, to help stop it happening again, I should “give it a good rev up every now and again, or take a good run down the motorway.” Please let me know how you go on Bill. Best regards,
Doc Diesel