My 2uzfe seems to be a hydrogen burner.

I’ve researched and found a lot regarding the head gasket problems or the lack of in these engines, but have not found anyone describe my particular issue this way yet.
The engines coolant is dropping in level by about .5-.75 gallons every 100-150 miles give or take. No leaks, radiator, water pump, thermostat and all hoses had been replaced by previous owner and she still had issues. And looking over the service records this seems to have maybe started a few years ago. A mech did a what he called an Head Gasket sealant additive application, for an hefty amount in 2022. Oil was last changed in December and 2500 miles ago. Currently has 234518 on it. My wife was offered the vehicle for $500 and jumped on. Now it’s my problem. Oil is amazingly clean, on occasion I do see a little milk under the oil cap or hi on the dip stick, but only on occasion. Has not used any oil. Block vent valve is working properly, all cylinders test within spec for compression without any out of spec drop between two cylinders. The combustion gas test is not the easiest on this configuration, but I did get a slight color change in the fluid, and I have noticed that the coolant system is under pressure even when the system is completely cold. Have not done a coolant pressure test, but have not had any sign of over pressure on the system, and it has not gotten hot on me, but has for the previous owner. I just check the level often to prevent any further or any damage. No noticeable vapor, other than what I’d generally consider normal during warmed up, from the exhaust either.
My knee jerk response would say head gasket, cracked head, or water jacket in the block.
Any recommendations for additional tests to narrow this down further or where to go next? I’d prefer not to replace the head gaskets to find out it is a crack head or block issue.
Thank you in advance for your assistance and contribution.

 

I have a friend who bought a fgt after i got mine. We talked a bunch about them while i was searching and apparently the bug caught him too.
He got a 2004 double cab with a 3" lift and 285 BFG ATs. Its a nice looking truck, vet drove it back and forth to work from 2004 thru 2021 and bought a new one to replace it. It had about 380,000 miles on it and was in great shape honestly. Vet is probably around 50 now and jusst bought a stock white double cab and replaced this one. My friend bought it, i knew the truck cause i go to that vet clinic with my dogs, i've talked to that male vet a few times and knew how long he had the truck. He sold it to my buddy and the buddy had no issues till he hooked a trailer to it. Pulling his lawn mower trailer it started overheating. He took it to a mechanics shop they said its head gasket. He kept driving it but wouldnt pull a trailer with it. I've talked to him a few times over the past year or two about it he said it just uses a slight amount of water and never overheats driving normally. He travels medium distances, nothing hours away but it has no problem on the roads, stop and go traffic in town. ZERO overheating just uses a little water. ONLY has a problem overheating when he is towing so he just stopped trying to use it to pull lawnmower around.

I suspect yours is likely the same. Put some real load on it and lug it down in high gear with a bunch of weight behind it and i bet it pressurizes the coolant and spikes the temp and burns a lotta water. I cant say how or why it doesnt have issues unloaded, but loaded is the only time his does it.

AND.... Last time i talked to him about it he had like 435,000 and still hasnt replaced the head gasket.

 

OP how about you pull some plugs and borescope the tops of some pistons? If it's steadily burning 1/2 gallon of coolant every 100 miles (that's a ton) there will be physical signs. Those pistons will be steam cleaned and free of carbon buildup

 

Funny you I overheats while towing, because that’s the problem the previous owner had. She was towing a horse trailer.
I however would prefer to not have to worry about it. My plan is to do a small lift to help get around in the desert here in Az, and in this heat will need every bit of the AC I can get and don’t need it overheating.

 

Good option Red. I was about to pull the plugs again to look at them again, but think I’ll acquire a scope and take a look at the cylinders as well. Even if I can discern what side the leak is on will help minimize the repair time and cost. Thx

 

Original radiator?


Mine had a bunch of build up in it and would temp spike in 105° degree weather. When it did, it'd push out the cap into the reservoir. If it fills enough to come out the reservoir, when it cools the level will be low.

New radiator fixed it.

 

If it a crimped radiator it could have a small leak from that and is hard to detect.

 

I've heard almost nothing about head gasket problems with the 2UZ-FE in our trucks, curious where you found this at? I've seen the 5.7L has head gasket issues, but we rarely see head gasket stuff (on here at least) in the years I've been here.

I see you saying "no leaks", but ... are you aware of all the places these trucks leak coolant? There's quite a few listed in the 'coolant leaks' bullet point over here, but I can think of at least a dozen different ways these trucks can lose coolant and you may not notice much of anything, especially if you have the wrong colored coolant (should have pink, not yellow):

1. The coolant crossover pipe, front gasket that terminates above the water pump will dump coolant into the valley
2. The coolant crossover pipe, rear gasket that terminates near the back of the block can send coolant down the back of the block
3. Block drains, one on both sides of the block, just below each manifold, you'll notice their metal tube sticking out
4. Freeze plugs, there are a couple on the engine
5. Bad radiator cap: I'd hope you'd see the spray, or the overflow bottle high, but it will definitely leak or spray oodles of coolant
6. Water pump, if not properly sealed, can leak coolant out the bottom
7. Oil filter housing has a coolant line going through it
8. Throttle body has a coolant line passing through it
9. Heater core, but I'd hope you'd notice th floors are damp
10. We've seen plenty of times where a tiny leak in the radiator won't present until the engine is up to temp, and engine running above 1,500-2,000 RPM.

Needless to say ... there are probably even more than this to consider. What I would recommend you to do is very simple: Stop fucking around. Don't break out the parts cannon. Get some an additive/dye that's coolant-safe. Put it in the cooling system. Go drive around for 30 miles. Come back to the house, throw on the glasses and break out the UV light, and see where you see traces. DO NOT forget to look at the back of the block, and at the top and bottom of the bellhousing. If you're leaking externally, you should see it. If not, look inside the tail pipe and around the manifolds, I'd hope some of the dye may be visible after being burned out passed out the ass-end? The fact the mechanic didn't do this in 2022 is mindboggling. Fucking idiot.

SKETCH! I know this isn't on you, but if it was a head gasket, with the amount of coolant you're talking about, (1) it'd be smoking out the tail pipe, and (2) applying fix-in-a-bottle is fucking stupid without evidence to suggest there's a head gasket issue. The potential side effects aren't worth it in the long run, and that should be a last resort only when you KNOW the head gasket is fucked.

This is 1,000% normal if you do short-trip driving in any vehicle, and notoriously so with these trucks. Short trip driving is very hard on engines, and many people neglect to change oil on 'time' versus 'miles' in that case, which really fucks with an engine. I know - my previous owner did it. At 65k-70k original miles, my heads looked like someone sprayed several coats of brown varnish in them and the valve covers were fucking caked with crust.

It can also be a sign PCV valve is old/failed, along with other stuff, but generally: PERFECTLY NORMAL for cap froth if short-trip driving.

 

Thanks Shifty,
I like the die idea, hadn’t thought about adding die. Hoping to break into it this weekend some more. It not a daily driver by any means, but when it does go out it a good 20 mile tip just to get to town. That’s why I make about 3 trips to town and add a half gal of water. I’ve been watch it pretty closely for any signs of exterior leakage and haven’t seen any signs. And why I am coming to the graces of Lord of the Tundras Shifty, you are renowned sir thank you! Before I go to the parts cannon
I have faith we will figure this out. Thanks again.

 

No, has new radiator. No visual external leaks.

 

Spot on; only thing to add is pressure test, throw 15 or so lbs in the radiator and see, see if it’ll hold that pressure, or how long it takes to bleed down; you might be able to find the coolant if it’s a bad enough leak. That combined with the uv dye should help you find your problem

 

Yep, got everything needed to do the I’ve and pressure test on the way and should be able to get those done next week. I’ll update then.
Thanks Everyone