Bought a used 3.4 with 100k on it... What should I do now?

[Jebb209]

So I bought a used 3.4 out of a Tacoma with 104k miles on it. Valve covers look like they have just started to seep as well as the oil pan.

Mine currently has 363k and I’ve just developed a coolant leak in cylinder 6. Instead of figuring out if it’s a head gasket or cracked head I’ve decided to just replace it.

Any maintenance items I should address other than the obvious leaks and timing belt? I’m very new to the Toyota scene so I’m looking for a little guidance.

Thanks!


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[Joelzy]

From my recent experience, I would start by taking off the valve covers and getting a look in the heads. When i did that with the “lower mileage” jdm swap i found a chocolate factory. Most sludge i’ve ever seen so i ended up rebuilding the high mileage motor from the ground up.

Good time to do HGs and all but i doubt most would go there without a reason.
Probably just VC gaskets, timing and fluids



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[absalom]

From my recent experience, I would start by taking off the valve covers and getting a look in the heads. When i did that with the “lower mileage” jdm swap i found a chocolate factory. Most sludge i’ve ever seen so i ended up rebuilding the high mileage motor from the ground up.

Good time to do HGs and all but i doubt most would go there without a reason.
Probably just VC gaskets, timing and fluids



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Good time to do HG's (head gaskets) on a motor with 104k?

OP, aside from the easy things you already mentioned, the only other thing I would suggest is perhaps plugs. Oh, and if it's an automatic, a new OEM radiator with genuine coolant -- will help you avoid pink milkshake.

104k is absolutely nothing for the 5VZ. Quite honestly, 363k isn't much either, as long as the PO was diligent with cooling system maintenance, which maybe they weren't.

 

[Joelzy]

Im just saying if the motor isnt currently in the vehicle and running, its a better time than if it was.
If i was going through the trouble to swap a motor in i’d probably take care of the few things that can go wrong on these motors beforehand. (I.e. headgadkets, knock sensors)
Maybe just me though


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[SilverRidgeRunner1]

I would replace every seal with factory new seal. Valve covers , rear main seal , oil pan, etc. Then on to the timing belt water pump. Upgrade the exhaust with stainless steel headers. Lastly upgrade the vacuum line with silicon..

 

[dogtail]

So I bought a used 3.4 out of a Tacoma with 104k miles on it. Valve covers look like they have just started to seep as well as the oil pan.

Mine currently has 363k and I’ve just developed a coolant leak in cylinder 6. Instead of figuring out if it’s a head gasket or cracked head I’ve decided to just replace it.

Any maintenance items I should address other than the obvious leaks and timing belt? I’m very new to the Toyota scene so I’m looking for a little guidance.

Thanks!


Sent from my iPhone using Tapatalk

In 2015 I swapped out a 3.4L with 112K, was all original including TB, which all looked great. I only replaced the wires, plugs, and oil. I hit 250K early June and replaced the original TB with and OEM kit, the motor is at 264K now. I drive it about 1,000 miles per week.
At 104K if verified correct and not BS, I'd inspect the TB and not replace the kit if good, they go easy 160K, mine I went 250K and actually still looked good, but I replaced it then. These motors are legendary with OEM parts, don't skimp with non OEM crap. You can replace stuff for piece of mind, but at 104K the motor is barely broken in yet if it was taken care of.
I'd be a little skeptical on correct 104K mileage on a 3.4L with leaking seals, easy to BS mileage on a pulled motor. In a non pulled motor easy to clock an analog odometer, digital cluster can be changed out with low mileage one. So watch for game playing.

 

[96RedRunner]

Two things that are a PITA to change with motor in; oil pan gasket at least snug up bolts and rear main though I never had problems in 370k miles on 96.
Also a great time for headers if there is even a slight chance you may want them.
VC's are going to leak thats a given, since intake needs to come off to tighten evenly all around, pull them see what lurks beneath cleanup if needed.
You pull oil pan first since easy to get to, if sludge is there it will be on heads.
With only a 100k miles half way taken care of with decent oil & changes your good I'd bet just putting it in. Use Rotella T6 Syn or Rotella T4 conventional oil for internal cleanup. Once in, cooling system chemical flush, use Toyota Red coolant.
My $.03 worth.

 

[19963.4lsr5]

I'd do the rear main seal and valve cover gaskets and timing belt kit.

Honorable mention is the head gaskets. It's far easier to do it now rather than later. The low milage limited (120,000 miles) had either a head gasket or intake manifold issue at 160,000. Then while she is driving my SR5 it's head gasket (at 230,000 miles) went and now I get to do mine. I'll admit it had a odd startup stumble cold for the last few months. Her driving 300 miles a week done it in.

With the engine on the stand I'd do it. Do it all. The yotaShop head replacement kit is complete. Only thing missing from the 97 kit was the Valve Cover grommets and the rear cam plug for each head.

If your replacement engine doesn't have the oil cooler, put yours on it if the passages are there.


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[Jebb209]

I really appreciate the quick responses! I think I've decided to do the oil pan, valve covers and timing belt as this is a budget replacement. Of course if anything else pops up while I'm tearing it down I'll take care of it.

Thanks again!

Should I keep my core or just get my $200 back?