Buying 3.4 90 series... Need advice!!

[chamberlain75 Lurker Find all posts View Profile Close chamberlain75]

Hi guys I'm new around here. I'm from Costa Rica, a small country in Central America. I've had my Prado 90 turbo diesel since '02 (since new, over 360k km) and it's completely equipped with ARB/OME stuff. I'm considering buying another Prado 90 but with the 3.4 V6 engine.

The idea behind buying this 3.4 is to transplant all the accessories from the turbo diesel to the 3.4. This because of..... I'm in need of more power. The problem started when my grandpa gave me his 93' Ford Explorer (4 liter V6) and since then I've been using it a lot to do my long trips and when I climb back to the Prado it's just powerless.

The other reason for this is that I broke the chasis (frame?) of my Prado two times by now. It's repaired though. So I had the idea to buy this 3.4 Prado so I can add all the 4x4 stuff to it and retire my turbo diesel Prado from the heavy driving and use it just for city driving or for the school run.

My 1KZ Prado has been the best car I've ever had, just routine maintenance and good to go. So my question is, how good is the 3.4 engine? Should I search something specific in it before buying it? How bad is the gas mileage? What do you think about installing the TRD supercharger?

The 3.4 Prado I'm looking after is a 50th anniversary edition 2002 model, it's in very good shape, has covered 160k km. The turbo diesel's are too expensive... What do you think about?

Francisco Chamberlain
90 series Prado
Costa Rica

[mjrandom Out of control poster! Find all posts View Profile Close mjrandom]

I don't think there is anything inherently wrong with the 3.4 but it can be heavy on fuel. Hopefully Glen or one of the others running the V6 will jump on. Mind you Glen thought his V6 needed a little more so he supercharged it. Have a look through the builds, it is a superb 90.

[Bushbasher Out of control poster! Find all posts View Profile Close Bushbasher]

I had one for 13 years and it was a (modified) beast too with all the fruit and totally reliable. Sold it at 180k. Only issues were radiator bottom tank cracked the seal at 120K, starter died at 150k, rear main seal went at 160K, and right front diff/axle seal went around the same time. Was pretty good on the fuel until you hooked up a trailer behind it and then it was terrible. But it still drove along at highway speed with big trailer behind.

[bacdj Junior Member Find all posts View Profile Close bacdj]

91 model Prado Grande, 3400

I had a 2001, Prado Grande, 3.4l, 95 series, for about 9 years. I bought it second hand from a friend and it was near new with 60,000km on the clock. I kept it for 9 years and towed a 14 feet caravan quite a bit and never had a single problem with it, although I do all of my own services and am a bit pedantic with detail. I also changed the valve timing belt at the required time and it was still like new.

I am a Prado lover and think the 90-95 series is a great vehicle. My only criticism was it is not greatly fuel efficient and the auto oil did tend to overheat a bit when towing, but I changed the auto oil after any significant kilometres of hard towing. From when I bought it had a noise in the drivetrain at certain times, but was never a mechanical problem and research found that some models did have this fault, but it was just a vibration/harmonics noise.

I have since bought a 20 feet van and traded up to a 2012 Prado Diesel for extra power and economy . I am very happy with this vehicle also and have not had any problems with just 42000km now on the clock.

Brian DJ

[glen_ep Addicted PP Member Find all posts View Profile Close glen_ep]

Hey Francisco,

The 3.4L 5VZ-FE is a great engine, reliable, has decent torque, quite easy to work on, but of course it's old by todays standards so does use the fuel.

The common issues are
- Stretched/cracked radiators causing occasional overheating issues. The radiator should be replaced with a brand new one every 200,000km / 10 years.
- Head gaskets leaking.
- Lower ball joint failure.

As you've found yourself, owners of 90 series are usually very happy with their vehicle choice. Those who are unhappy with their 3.4L engine and decide to change to something else, are typically unrealistic about fuel economy. 16L/100km is a very common average usage. Best you can expect is 13L/100km on highway doing 95km/h (go faster and it will quickly climb to 16L/100km). Off road generally 16-17L/100km. I recently traveled though Australian Simspon Desert (sand dunes) and used 21L/100km.

TRD Supercharger is fantastic of course, I have one in mine, but for most people it's too expensive to purchase. Supercharging or turboing the 3.4L does increase the chance of engine problems, primarily pre-detonation, but done correctly it will still maintain it's reliability. I've just completed an outback trip, covering 10,000km and very remote regions. I pushed the engine/supercharger hard many times on large sand dunes and it only complained once - on the biggest sand dune when running low quality fuel with an octane boost. I switched over to the high quality / high octane fuel, and all was resolved.

Some people in the USA (and probably the middle east) have installed turbos on the 3.4L, so that may be another option for you.

Another option is to transplant a 1UZ v8 engine, but there's a lot of work involved.

[glen_ep Addicted PP Member Find all posts View Profile Close glen_ep]

I don't think there is anything inherently wrong with the 3.4 but it can be heavy on fuel. Hopefully Glen or one of the others running the V6 will jump on. Mind you Glen thought his V6 needed a little more so he supercharged it. Have a look through the builds, it is a superb 90.

hehe, thanks for the complement!

[mjrandom Out of control poster! Find all posts View Profile Close mjrandom]

Has anyone thrown the 4L V6 into a 90? Should be doable and maybe easier than alternatives?????

Glen, just telling it how I see it.

[RanJ Avid PP Poster! Find all posts View Profile Close RanJ]

Has anyone thrown the 4L V6 into a 90? Should be doable and maybe easier than alternatives?????

Glen, just telling it how I see it.

Yeah but nah but... the amount of engine and trans mount modification required and the electrical modification required to bring it up to scratch... i would imagine that the d4d would only be a stones throw away. Not as much hp as the 4.0 but better than the 3.4.

[glen_ep Addicted PP Member Find all posts View Profile Close glen_ep]

I'm pretty sure I've read the 90 is sold in some countries with the D4D?

[oceanracer Moderated member Find all posts View Profile Close oceanracer]

I recently saw 1000ks com from both tanks, I find it better not to look at the cost just go and pay.