ASK THE EXPERT

Hey Adam,

I drive a Diesel Prado and am looking to upgrade our caravan to a larger size. The van will be within the Prado’s towing capacity but I have heard a few horror stories. How do the Prado’s handle towing a larger van?

– David.

Hi David,

Good question actually.

There is no escaping the fact that emissions are the major contribution to the design of modern day vehicles and 4WDs.

We keep seeing smaller motors hit the market with turbos added to boost their power. You will have to always remember that it is a smaller engine and we are asking a lot from it, especially when towing up a long hill.

What happens when towing a long hill is that the 4WD struggles a bit and the speed of the engine slows.

We tend to then push the accelerator to the floor which pushes more diesel into the engine but the turbo is slowing down making less boost, therefore less air going into the engine.

In diesels, the more fuel that goes into the engine the hotter the engine temperatures are. If the turbo isn’t pushing in as much air the engine gets hotter, which can cause engine failure.

This is also a problem with the 3.0L Patrols. I would suggest slowing down, keeping the revs a bit higher – but do so within the turbo range, by changing down a gear. That will definitely help with the longevity of the engine.

The Prado’s also suffer from ‘carbon-ing up’ of the EGR valve and wearing of the diesel injectors in a lot of the D4D engines. I suggest having the injector feedback values checked as that can give you an idea of the condition of the injectors.

The lower injector seals also leak, so replacement also recommended but at some stage the injectors will also need to be replaced.

When the injectors wear they can actually drop diesel onto the piston instead of spray the diesel in, which burns the pistons. I recently had a customer with a 120 Series D4D and he’d burnt a hole in the top of one of the pistons.

I do believe the Prado can handle it but it will need good maintenance and driving styles may need to be adjusted.

The larger engines like the 200 Series and the Y62 Patrols will do a much better job but it comes at a cost. Incidentally my customer whose Prado engine failed moved into a Y62 Patrol and he loves it. It’s also pretty decent on fuel.

The old saying “There’s no substitute for displacement” … well it helps.

GO NUTS!

Adam