Ask Smithy: That's so uncoolant

SMITHY answers readers' questions on everything automotive.

corolla

SMITHY answers readers' questions on everything automotive.

The service manual states that the engine coolant in my 2008 Toyota Corolla Seca Conquest should be replaced initially at 96 months or 160,000km and thereafter every 80,000km. Also, it does not specify any requirement to change the automatic transmission fluid. I have no wish to spend more money on servicing than necessary but the engine coolant change interval seems too long to me and the absence of advice to change the automatic transmission fluid is puzzling. I intend keeping the car for a long time. Would it be prudent to override the service schedule for these items and change the fluids ahead of the times stated?

- T. Bignell, email

The initial coolant change is at eight years, which would seem way too long. I would be looking to change the coolant every couple of years, that's 40,000-50,000km.

As for the automatic transmission, car makers now employ a fill-for-life strategy, which means they fill the transmission in production and never touch it again. My view is that it's a flawed approach, particularly if you plan to keep your car for a long time - as you say you intend to do. I would have the fluid changed every 50,000km and have the transmission serviced every 100,000km.

STIR OF ECU

I've got a 2005 RAV4 Cruiser automatic. I've heard that there were some issues with the automatic transmission for some RAV4s due to the ECU (electronic control unit). So far I have not had an issue with the car. What are the telltale signs of any imminent problems with my auto?

- Ric Lau, email

There is a problem with the ECU controlling the automatic that can result in the clutches in the transmission burning out. It was so common that Toyota recalled RAV4s in the US to fix them but Toyota Australia chose not to recall the cars here. Watch for rough shifting, reluctance to shift, jerking and rough running.

CONTROL HUB-BUB

Recently the VVTi control hubs in the top of the engine in my 2007 Toyota Aurion failed. The repair cost was about $3000. The dealership was helpful and negotiated with Toyota to assist with the repair costs. My contribution was about $900, as the car was out of warranty, even though it had only done 75,000km. I feel that the failure of the parts was because of a manufacturing fault and wrote to Toyota seeking a refund of my costs, but Toyota has refused my request. Do you know of this failure with the 3.5-litre engine and is this outcome the best I can hope for?

- Robert Briigmann, email

We haven't had any other reports of a failure of the VVTi hubs but perhaps other readers might tell us of any they've had. The outcome you've managed is a reasonable one.

OIL OUT

Before buying a new Holden Captiva, the Series II AWD 2.2-litre diesel, we particularly discussed with the salesman our purpose for the vehicle, that it would be used around town, and he recommended the diesel for the best fuel economy. The vehicle is advertised as the most fuel-efficient in its class, with advertised fuel consumption of 8.3 litres/100 km combined, 10.6 litres urban and 7.0 litres extra urban, but we cannot get any better than 12.8 litres. I am very unhappy with the high fuel consumption and have written to Holden and the dealer to have my vehicle tested under supervision but they continually say it may get better without actually doing anything. I asked the Fair Trading office, which just sent me the Green Vehicle Guide - which again informs me of the fuel consumption my vehicle should be getting. I would like a replacement vehicle that will deliver the advertised fuel consumption.

- Judy Kirkby, email

You have experienced the problem that is the fuel consumption guide. The fuel consumption in the ads and the guide are the results of tests done under laboratory conditions and not necessarily an accurate guide to what might happen in real life. They are meant to be used to compare one make and model against others. They're not intended to be an outright measure of real-life fuel consumption. Request that the dealer and/or Holden thoroughly check your car.

TRANSMISSION VAMP

Intermittently when upshifting, my 2005 AH Holden Astra automatic will hang on in second for a few seconds and then lose drive. If I flick the shift into neutral then back into drive it re-engages. I can also be driving along at 80km/h in top gear and it will also just lose gears, as if it goes into neutral. I have had the transmission changed twice under warranty, but this has not solved the problem.

It has been back to Holden and it says it can't find anything wrong. Any help would be great as this is very frustrating.

- Terry Bojczuk, email

That's a tough one but you would have to think it's external to the transmission given it's been replaced twice. It could be a number of problems, from a speed sensor, the gear position switch or the ECU. Get it to an auto transmission specialist and have it checked.