3.4L engine Maintain or Replace?

Hello All,

I just bought my first Tacoma, Black '99 Tacoma 3.4L XtraCab TRD. The engine weeps oil from the valve covers and possibly from the rear main (could just be oil collecting from the valve covers). The truck has 300,000 mi and I am trying to decide if I should do some preventative maintenance (replace valve cover gaskets, timing belt, water pump, etc.) or if I should drive it until the engine dies (doing bare minimum maintenance) and just replace/rebuild the engine.

Are there some tests I could run to determine life expectancy and if it would be worth replacing mission critical components and or start looking for crate engines/ re-builders? Tell tail signs of decline?

Other advice to a fresh owner? Recommendations for crate engine suppliers or re-builders?

Thanks for anything!

 

I mean if it isn't sludged up/obviously abused/neglected I don't see why it wouldn't go 500k+, the 3.4L is one of the best V6 engines Toyota made.
There's a member on here that has nearly 800k on his and it's been supercharged most of it's life.

I'd for sure fix the valve covers as that's a pretty cheap and easy fix.

Other stuff I'd say as needed.

Do you have any history on the truck?

 

No history on the truck aside from some obviously new suspension components, plugs and wires. Which makes me worried about the state of the timing chain. I suppose I could start pulling the covers back and taking a look at things.

 

It's just the timing belt, no chain.
It's easy enough to pull one of the upper timing covers and inspect the belt.

The 3.4 is non-interference so the odds of damage from a broken belt are pretty low.

 

Welcome to TW…

 

Bro you’re sittin' on one of the best motors Toyota ever made, the 5VZ is a damn tank. Just 'cause it's got some oil weep doesn't mean it's time to start shopping crate motors and letting it rot.

I'd do the work. Valve cover gaskets, timing belt, water pump — basic stuff that’ll keep it happy for another 100k easy. Waiting for it to “blow” is just asking for it to leave you stranded when it didn’t have to.

You’re not saving money by skipping maintenance.. you’re just delaying it until it costs 5x more.

Freshen it up, drive it like it was meant to be. You bought a legend, don't treat it like a beater. (Or do… up to you)

 

I might suggest running a compression test. If you get any wonky results there, maybe pause on getting everything up to snuff, until the cause of low compression can be determined.

I say this because cracked heads or failed head gaskets (both of which can cause low compression) are the usual suspects when a high-mileage 5vz finally kicks the can.

If you'd owned the truck for a while and could definitively say the coolant level has stayed consistent for several thousand miles or so, then I'd say just jump right in and fix those leaks, replace the timing belt and water pump, and send that sucker for another 300k.

Overall though agree with the sentiment shared by others that the 5vz is an absolute tank. Mine has 294k miles and runs like a Swiss clock. Take care of it, and it'll take care of you