While the engine is out
 

I'm sitting right at 290k miles on my '03 V8 Limited. I've had it 4 years now and have been watching the rear main leak get worse and worse. I've also noticed that after it sits for a few days (this happens a lot) it smokes pretty bad on cold starts and uses more oil when doing a lot of low rev driving (in the woods and mountains). Last year when we went to NM, I pulled my camper to Carlsbad 500+ miles. It didn't use enough oil for me to notice. I used nearly half a qt of oil each day we spent riding around Queen and Cloudcroft, then none on the drive home. I'm pretty sure the valve seals are leaking causing oil consumption and smoke, this has also wreaked havoc on the cats. I notice this morning that there's oil leaking from under the front cover. This could be from the front seal or the cam seals. I've also been fighting exhaust manifold leaks off and on for a year or two now.

I said all this the say that I'm going to plan on pulling the engine this spring and address all these issues at once, out of the car. My plan is to
-pull the engine
-pop the heads and send them out to be resealed and adjust the valves
-reseal everything, including exhaust manifolds

for those who have done it, is there anything else I should look into while it's out? Are there any other mileage related items I should look into?

How much is all that going to cost?

Would it be cheaper to pick up a motor with decent miles from a recycler instead of opening up yours and redoing it?

A quick search on rock auto shows a seal kit for about $150. I've got time to check prices and find a better/cheaper one. I haven't checked with any local machine shops on these heads, but I would assume the head job would run between $200-$300/ea. I'mm thinking I'll go ahead and do the alternator and p-steering pump while it's out. They're both originals.

I don't know what a pull-out engine would cost, but i don't think I would go through the trouble to install one without giving it the same treatment.

Timing belt and water pump for sure and it would also be a good time to replace the starter since you'll have the intake manifold off. But wouldn't it make more sense to replace the engine with a lower mileage one from a salvage yard instead of spending all that time and money rebuilding just the top end on a 300k mile engine? I know a "lower mileage" 03-04 non-VVT 4.7L engine can be had for relatively cheap compared to its 05+ VVT counterpart.

I was faced with a similar situation when my radiator cracked which caused the engine to overheat but ultimately I decided to fix it after pulling the heads and seeing that the cylinder walls, cams, ect had very minimal wear.

with that mileage, you may as well address the bottom end also. no sense to go through the trouble of pulling the entire thing, only to put it back in untouched.


rebuild, or replace it with a lower mileage one.

Expensive engine to rebuild. A gasket set if I remember correctly was $400.

Rebuild with 1UZ rods (beefier) and put a supercharger on that sucka.

Rule of thumb is never reseal or partially rebuild an engine with that high mileage. It will make the engine too "tight". Sounds weird I know but its true. I have seen and been around too many high mileage engines that have had heads rebuilt or have been opened up and resealed with untouched bottom ends blow up pretty quickly after all the work is done.

I realize the 4.7s are a great engine but redoing the top end could or will create other issues on the other areas that are worn.

My suggestion is rebuild it since you know the engine is sound. If not go for a used engine ( possible future issues as you dont know what its been through), or get a already rebuilt engine with a warranty from say Powertrain products. It may be higher in price but if something happens you would be covered parts and labor.

Good luck.

I guess there's probably little chance that the bottom end wouldn't need work done. Maybe it would be better to start with a lower mileage pull out. I found one semi local, advertised as a running core with 150,000 mile for $300. Something like that might be a better starting point for a complete rebuild than mine. If mine would need any cylinder work, I would get the $300 back in machine work alone. This would give me a chance to piece all the parts together and get the engine ready to drop in. I could have it out and back in and running over a weekend.

Why don't you run a cylinder pressure test and decide from there.

I did a leak-down test a year or so ago when I first noticed it using oil, all cylinders were around 15-20% iirc. This is why I was originally considering just doing the top end. I believe the bottom end is in good shape, for its age. After putting a pen to it, I do believe I can swap in a junkyard engine cheaper than I can go through this one. I think I can get a pull out with about 150k miles, reseal it and do the water pump and tb for about $1000. I figured I'd be that far into my current engine with only doing the top end.

This brings me to the next question. Will a tundra engine swap in? I think I rember there being differences like the fact that the tundra and sequoia engines use a timing chain and maybe a different intake, but will they interchange? I've found several very low mileage (sub 50k) tundra engines for the same prices as the 4runner/GX engines.

Have never heard anything about any 2uz without timing belts. Someone please correct me if so.

if its a chain, its a different engine, probably the 5.7. as far as it being swappable...with enough money yes, anything is. I doubt it will be cheap, or easy however...

stick with a 4.7.

The '03-04 Tundra and Sequoia 4.7L will also work. The '02 and earlier 4.7L uses a cable throttle body while the 03-04 uses a drive-by-wire TB.

I'm guessing he's referring too the 4.6 UR-FE which replaced the 4.7 2UZ-FE in 2009/2010 and does indeed have a timing chain.

I'm guessing it won't be a direct swap, but not sure or we would of heard of others doing it.