I have to get a new engine and I thinking about doing the 3.4 swap. I've been told that the 3.0 doesnt last long even with replaced head gaskets...does anyone know how reliable the 3.4 is?

I just replaced the head gasket on my second 3.0. It runs great now, but that is not a very strong (or powerful) engine I would look into the 3.4. I went with a better and more expensive head gasket then the stock one so I expect good things from that. Like I said I haven't had it that well, but it runs awesome right now

Been running over seven years on the HG's Toyota put in with no problems. The swap depends on how handy youm are with the wrenches. The 3.4 is an outstanding engine, but it is not a bolt in swap, exhaust is one thing it goes down PS on the 3.4. Not a big problem for a good muffler shop.

I would probably not do head gaskets again on my 3.0L. 3.4L for me. I think another issue you have to deal with is the oil pan and sump. Tacoma 3.4L's have a different suspension set up so the sump is at the opposite end of the engine, (don't remember which is which). If you get a 3.4L from a T100 I think it will fit ok though. Other people can verify this better probably.

With the new head gaskets that problem doesn't seem to be an issue any more.

I think the 3.4 is a very good engine but the 3.0 aint all that bad either. For what you could spend on the swap you could likely build an really nice 3.0. I have a buddy who is currently testing some mild cams for the 3.0 and initial results are good both milage and powerwise.

I'll be testing the next stage cams on my built 3.0 sometime in the summer. If all goes well I should have more power then the 3.4, better milage then stock and toyota reliability. It will cost me close to if not less then the cost of a 3.4 swap.

As mentioned premature HG failure isn't that common anymore, except for the installs that were done wrong. i.e., re-used headbolts, block and heads weren't flat, didn't torque correctly, etc. I have gone 8yrs, 6yrs, 2yrs and counting on oem HG's w/o failure, the first set was replaced due to hydro-locking the engine after a failed river xing <img src="/forums/images/graemlins/smile.gif" alt="" />, and the last two have been for burnt valves. If you are planning on doing the work yourself, you can rebuild the heads, gaskets, misc. parts, along w/headers/exhaust for about $2k.

Since I have done the HG myself, if they were to go, I would replace them again, the way I have my 3.0 set-up it really wouldn't be worth spending $4500 for a 3.4. Now of course if 3.4's ever drop down to about $500, and the ORS complete install kit drops below $1k, I would have to reconsider. <img src="/forums/images/graemlins/lol.gif" alt="" />

What is the deal with the burnt valves on the 3.0L? I have not heard that much about it, but that is exactly why I had to do mine. I bought it from the original owner with 2 burnt valves. She had the receipts to show that the dealer had done the HG recall only 30K before, but still two burnt valves. I'm thinking maybe they were not adjusted correctly. I am going to check my plugs to see if the mixture looks right also since that could be a cause. I do not want to do the HG again.

Cylinders #5 & #6 exhaust valves are susceptible to excess heat due to the head design and the exhaust manifold crossover tube. From what I have read, number 6 is especially likely to burn. I have also read ( tho I find it a little difficult to believe ) that the valves on these engines get tighter with use, not looser. It would fit, tho, that if the valve gets tigher with age and use,, it would eventually not seat completely and allow combustion flame to escape. I'm just patiently waiting for my 3.0 to die. Right now, I'm not having any problems with mine -- 183,000 miles on it (crossed fingers).

Make sure you keept the cooling system in top condition and don't run the AFM too lean. Basically, keeping the engine in proper tune is probably the most helpful. Also make sure the O2 Sensor is operating properly.


Mike in AR

2 grand to replace the HG's yourself and have the heads rebuilt? Isn't that a little high? <img src="/forums/images/graemlins/confused.gif" alt="" />

You forgot the headers and exhaust in that mix. That seems reasonable to me.