I know the 4.0 has more power but I was wondering what does everybody think about the reliability between the two. I use to have a 3.4 4runner and I never had a problem with it, I am still kind of new to the 4.0.

I put over 205,000 miles on my 2nd gen 3.0L and last I heard from the guy I sold it to it was still running fine after 375,000 miles.

I put over 152,000 miles on my 3rd gen 3.4L and it ran as if it just came off the showroom floor.

I only have 39,000 miles on my 4rth gen 4.0L but from all indications it'll do as well as my previous T4R's, let alone the 2 other Toyotas I had that went 178,000 and 215,000 miles before selling or the Camry my son is driving with over 180,000 miles.

And all 3 of the T4R's were/are tow vehicles.

heres some info on both the 4.0 and 3.4.
reliability wise it will about the same. essentially you could get a bad engine on both but the odds should be about the same and there are cases where people have hundreds of thousands of mile on both engines, so it just comes down to how you take care of your car, or you just get the odd one out.

The 1GR-FE is the 4.0 L (3956 cc) version, designed for longitudinal mounting in RWD and 4WD pickup applications. It has a 94 mm bore and a stroke of 95 mm. Output is 236 hp (176 kW) at 5200 rpm with 266 lb·ft (361 N·m) of torque at 4000 rpm on 87 octane, and 239 hp (178 kW) at 5200 rpm with 278 lb·ft (377 N·m) at 3700 rpm on 91 octane. This engine features Toyota's VVT-i, variable valve timing system on the intake cam and a compression ratio of 10.0:1. An updated version of this engine features Dual VVT-i, increasing output to 254 hp (189 kW) and 270 lb·ft (366 N·m) on 87 octane and 285 hp (213 kW) and 289 lb·ft (392 N·m) on 91 octane. Inside, the 1GR uses a taper-squish combustion chamber design with matching pistons to improve anti-knocking and engine performance, while also improving intake and fuel efficiency. Toyota adopted a siamese-type intake port, which reduces the surface area of the port walls and prevents fuel from adhering to such walls. This engine has special cast-iron cylinder liners cast into the block, which are a spiny type to improve adhesion between the liner and cylinder block. With these special thin liners it is impossible to bore the block. In the event of cylinder wall damage (scoring, deep protrusions, etc), the entire cylinder block must be replaced. For increased block rigidity, the 1GR also receives a high temperature plastic insulator/protector, which fills the empty space between the outer portion of the cylinders and block material common to open deck engines. For increased cooling efficiency, the 1GR employs water passages between the bores of the engine. There are two such passages for each bank for a total of four. This reduces cylinder hot-spotting and keeps combustion chamber temperatures more uniform.


The 5VZ-FE is a 3.4 L (3378 cc) engine which replaced the 3VZ-E. Bore is up to 93.5 mm (3.7 in) and stroke is 82.0 mm (3.2 in) while the compression ratio stays the same as the 3VZ-FE at 9.6:1. Output is 183 hp (142 kW) at 4800 rpm with 217 ft·lbf (298 Nm) of torque at 3600 rpm. It has a cast iron engine block and aluminum DOHC cylinder heads. It uses sequential multi-port fuel injection, has 4 valves per cylinder with bucket tappets and features large cast connecting rods, a one-piece cast camshaft, and a cast aluminum intake manifold. It also features an oil cooler and coil-on-plug ignition.

Wow that was an awsome explanation on the 4.0. Thank-you. What it kind of sounds like is Toyota did a lot of preventive add on's to the 4.0 but if something still goes wrong than it does effect a lot more of the engine. How would I tell if my engine has the updated dual VVTI?

The 4th gen, 2003-09 MY, were all single VVT-i. The 2010+ 4Runner, 5th gen, has the new dual VVT-i 4.0 V6.

If the oil filter is a traditional spin on filter mounted in front of the driver side valve cover (next to the oil fill cap), it's the original single VVT-i 4.0 V6.

The dual VVT-i 4.0 V6 has uses a cartridge oil filter and it's mounted down low towards the bottom of the engine--it's not accessible from up above through the hood.

There is an actual increase in power with high octane fuel???

Yes, but its not instantaneous. I remember reading a very well written article about running higher octane fuel is various engines. Toyota's ECU's apparently incrementally adjust timing to just when knocking occurs and then back off a little for maximum efficiency. In this case, consistently (I mean like 5 or 6 tanks in a row) running premium fuel will allow this gradual timing advance to occur which is where I believe the small additional horsepower/torque numbers come from.

yes like Synister said. but if you want to get the power faster from the higher octane you can go into walmart and buy an octane booster for like $3 and you mix it with your fuel and it is suppose to help increase the power faster.

oh i love my 2007 v6 to death but it has been at the dealership for 50 days now getting its engine rebuilt. i had a manufacturing defect (what they told me) where my exhaust value broke free and bounded around in one of my pistons shattering it, cracking 2 others then blowing about a 4 inch hole in my block then another about 2 inch hole in my oil pan. but this is rare i have only read about 3(including mine) that they have reported engine failure on the 4.0 v6. and i would suggest a warranty........but thats just me, i have a 7 year 100k.

I've been using Shell. 87 contains up to 10 percent ethanol. 89 contains up to 5 percent ethanol. 91 "V-Power" contains no ethanol.

The fuel consumtion display showed a reduction of 1 to 1.5L/100 km when I switched from 87 to the 91 maybe because of the no ethanol but also maybe because the engine gets more spark advance more often (= more power/efficiency).

But I believe, despite how sophisticated the spark advance management and combustion chambers/intake ports may be, a 10:1 engine will very much appreciate the higher octane like a chimp enjoys ripe bannanas.

Would you please share your source for this info?

By the way, 89 octane is simply a 50/50 mix between 87 and 91 done at the pump. There is no "89" tank at the station. Naturally the ethanol in it will be an average of both fuels.

Ethanol is one of the biggest scams being forced on the consumer right now.

I agree, I have over 100k on mine and it's running like the day I bought it. I've only done plugs and fluids in it. In the truck I stick to the cheap gas.

For my MR2 I only use Shell as they have 93 octane around here (necessary for the 10.5:1) It's usually the same price as 91 octane and runs great.

One odd thing is the FJ Cruiser says to use premium - it's the same 1GR we have though!

The 4.0 has a timing chain while the older V6s had timing belts. This, in and of itself, is not a problem, but it is more maintenance that must be done as the belt should be changed at some interval. As far as reliability, perhaps give a slight edge to the chain, but if either fail it will be catastrophic.

The Shell pump. Where you stick yer credit card in and push a big button and then it makes a whirring sound and then you squeeze the trigger and then fuel comes out.

Bear with me here: So in Canada at your Shell station there's a sticker or something else that tells you how much ethanol is blended in with each particular fuel grade? If so, that's great and worth paying the extra 6-7% that 91 usually commands over 87. Down here in Kalifornia all the pump states is "Contains ethanol" or "Contains up to 10% ethanol". The actual amount is supposed to vary throughout the year. I've considered getting a test kit so I can try and find who consistently has the lowest ethanol content. I'm actually also considering 100LL for fuel storage for my Honda EU2000i generator because our junk pump gas ages so quickly it will foul the jets in the carb in a matter of weeks if you don't drain it from the bowl regardless of whether you added Sta-bil . I'm still holding out for that station that somehow is sourcing straight gasoline but I think it's a mandatory thing.