Preemtive rebuild for a 3.4?

[Utah KJ]

I bought my 3rd Gen 4Runner almost 3 yrs ago for $1,800 when the dealership I was working at took it in trade on a new KIA. At the time, it had 197K miles, needed new rotors, new CV axles, the rear drive shaft rebuilt, timing belt and valve-cover gaskets. I spent $1k on these repairs and still felt that I was ahead of the game. Since that time, I had to replace the radiator and thermostat in 2012 and most recently, replaced the tie rod ends and odd bits on the steering rack that wore out and made the truck un-alignable; with new tires, that cost me $1,700.

Besides fuel and insurance the cost of ownership has been just under $5k which I still believe is great and I still did well. My 4Runner (D.A.V.e) has taken me all over the Rockies and over the summer towed a covered dual axle trailer from Missoula, MT to Ft Lauderdale, FL (that was scary on multiple levels). D.A.V.e now has 234K miles on the OD, I'm the 8th registered owner so the entire maintenance history is impossible to be had and I know stuff doesn't last forever. I've been told that the 3.4 is great and will go beyond 300K miles with proper maintenance but I wonder where I'll be when D.A.V.e's heart just stops beating?

Does it make sense to rebuild a perfectly good running engine (and the trans for that matter) for the insurance that it will go another 200k miles without leaving me stranded? What kind of scrilla would I be looking at? I am looking at this or riding my luck until D.A.V.e goes gently into that good night and buying something new... but that means car payments and debt sux.

 

[tacoma_AL]

I'm in the same boat with you and trying to convince myself to just get a JDM engine with 20-50k on it and build it outside the truck and swap it in. My current 5vzfe has 218k on it has been rebuilt twice and I'm still chasing ghost issues as well as electrical gremlins. I love my truck to death, has allowed my wife and I to go to and see some incredible places. Some days though I feel like rolling it down a fracking hill on fire to send it out in a blaze of glory. Of course all my problems started in Alaska when my block heater decided to take a poop. I believe if the engine is running strong, just keep on with the regular scheduled maintenance and you should be good to go.

 

[washington taco]

I would think it will give you warning signs of impending boom! I have over 300K, but am the sole owner and intend to dive it till its dead. Drive it till it starts to use oil or starts knocking at high RPM.

 

[SGTCap]

Really it depends on you and your desposable income and the resources you have available.

As mentioned above, you should get some warning before the engive goes. Unless there is a breakage in the timing set, a balancer comes apart, or something of that nature. Generally they start losing power and consuming oil and that's a good indication that it's time to start looking at options for a new engine.

My 4.0 is about to roll past 200k and I have no intention of replacing it untill it tells me that it's time.

On the other hand if you find a good deal on an engine and can do the labor yourself with relative ease and without straining your bank account too much I see nothing wrong with a preemptive engine swap.

 

[RememberTheFallen]

A fairly easy test to gauge the engine is a leak down test or compression test. Rent a tool from you local parts store and check the compression of every cylinder. You can find the "normal" values online or in a lot f service manuals. This will give you an idea of much wear you have and when to expect to rebuild.

If it is still running good then I would leave it alone.

 

[DaveInDenver]

Surprise failures can happen to any engine, like a freak thrown rod or timing parts or the like. I agree with other comments that I would drive it until it gives you some indication that it's tired like loss of power, knocking or something. The 5VZ should go 250K on oil changes mechanically but all engines eventually wear out and it's not until you replace or rebuild do you realize how long it was losing power.

 

[Martinjmpr]

What transmission are you running? Only reason I ask is that if you're approaching 250k, I would worry as much (or more) about an AT failure than an engine failure.

OTOH, manuals are pretty much bullet proof unless you abuse them. But ATs are pretty complex machines and it would be a drag to spend all your "maintenance" money on a non-essential engine rebuild and then have your transmission go out.

 

[montypower]

Those motors are good for 350-400k no question if maintained properly. I've seen many in that range (all original). Transmission is the same deal. With proper maintenance, cooling and not overloading it there is no reason it can't go over 300k. That motor / tranny setup is one of the most reliable Toyota has made. Extremely durable.

Maintain it. Drive it. Enjoy it.