3.4 vs 4.0 reliability

[Keros]

Very much shooting from the hip, I would say based on a lot of what what's already said here and in other threads, both motors will return similar reliability. If defining reliability as problems per distance driven.

However, it's likely that the cost of ownership of the 3.4L will be lower over the entire service life of the original build of the motor, given proper maintenance and care... based on the assumption that there's just less bits to go wrong with it.

The 3.4L is, in terms of ultra modern engine design, an antiquated boat anchor. There's nothing fancy, nothing special; just good ol' robust tough as nails get 'er done no matter what design. I would surmise it probably run ok on anything that resembles gasoline... like that found in places Toyota would expect its more... global... customers to need a gas burner.

The 4.0L is more a complex motor and its timing chain system, although very reliable, can have problems and servicing it is very expensive. It's a more civilized motor for civilian life, where emissions laws apply.

I think it's a tough discussion based only on the reliability of the two motors against each other because there's no truck that came with both motors (that I'm aware of). So, I think the discussion of the rest of the chassis is more the selling point.

 

[T4R2014]

1GR more civilian? It actually is less smooth(I want to say harsher but don't want to insult anyone) than a 3.4 with its timing chain noise and various ticks. Mind you a little harshness is appealing and why a lot of people like the bare bones XJ Cherokees so don't look at engine noise as being bad.

 

[Slowgoat]

My 95 3.0 blew at less than 200,000.

My 04 4.0 has 205,000 and still rolling.

For what that’s worth.

Knock on some wood real quick!!

 

[CougarHound]

I like the 5VZ-FE better because of the robust design. Solid closed deck iron block. Not surprisingly, there have been a few head gasket failures on the new engine.

 

[Stampeed Valkyrie]

I just recently sold my 3rd Gen 98 4Runner with 193K on the clock... its worst issue was leaking valve covers at about 150K. Other then that it was solid, no oil burning, no smoke.. etc.

I have replaced my 98 with an 08 V6 and the first thing I can tell you is power. The 4.0 absolutely crushes the 3.4. Time will tell on reliability but from what I read and what car folks tell me the 4.0 is pretty solid as well.

I miss my 3rd gen, but I don't miss the lack of power it had in comparison to the 4th gen.

my .02

 

[w210210]

Dont forget 5VZ has Iron block which means it will outlast 1gr fe ...
1gr fe dont have a good lifespan as 5VZ ...
5VZ is non interference engine ... so when timing belt will broke it wont destroy the engine ..
1GR has many problems like head gaskets ....

 

[hinmo24t]

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.

39k on your 4th gen? reminds me of the 2005 WRX i bought in 2012 with 38k miles from dealer...i learned low mileage like that isnt always a good thing. the waterpump seized soon after from not being driven enough and the belt burned off while driving and cost me $3G in new valves. i was informed that if too good to be true with vehicle mileage it can be true, because if you dont use it you can lose it.

good luck with the truck

 

[scott c]

Dont forget 5VZ has Iron block which means it will outlast 1gr fe ...
1gr fe dont have a good lifespan as 5VZ ...
5VZ is non interference engine ... so when timing belt will broke it wont destroy the engine ..
1GR has many problems like head gaskets ....

Hi folks, Just new in posting here. I'm looking at 3.4 and 4.0 4runners for a purchase, and all have over 290,00 kilometres (about 185000 miles). motorreviewer.com states that the 1GR-FE 4.0 has cast iron sleeves that are too thin to bore out, so a rebuild is not possible and another cylinder block must be found. The same applies to the 3.5 V6 FE motor. As far as I know, the 3.4 can be rebuilt using the original cylinder block. Does anyone else have knowledge of this? thank you.

 

[stevedonato]

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.

FYI: Not catastrophic on the older 3.4L V6 because it was a Non interference engine (valves would not hit the pistons on a belt snap). While chaines rarly break, but if it did the 4.0 V6 engine could most likely be distroyed.