Blown head gasket or just short driving?

A little bit of misinformation can go a long damn way.

(1) Starting position: Radiator filled, overflow reservoir filled between "LOW" and "FULL" level.

(2) Normal operation 1: Engine warms to normal operating temperature and pressure, thermostat opens, coolant circulates through radiator. Normal engine temperature maintained.

(3) Normal operation 2: Engine is heavily loaded on a hot day, radiator cap set pressure exceeded, coolant overflows to reservoir, reservoir below "FULL" level but above "LOW" when hot. Engine shut off, coolant cools and "shinks", vacuum pulls excess coolant from reservoir back into radiator.

(4) Normal operation 3: Over years of neglect, hot coolant flashes off in reservoir, and evaporates, and reservoir level drops to or below "LOW" level when cold. At some point, if coolant is not replenished in overflow reservoir, the level will fall below end of pickup tube in the reservoir.

(5) Abnormal operation 1: Engine is heavily loaded on a hot day, radiator cap set pressure exceeded, coolant overflows to reservoir which is now below "LOW" level. Engine shut off, coolant cools and "shrinks", pulls air back into radiator, vacuum now broken. No coolant can be drawn back to radiator from the reservoir.

(6) Abnormal operation 2: Engine is heavily loaded on a hot day, neglected cooling system temperature is above normal, radiator set pressure exceeded, MORE coolant is lost to reservoir. Overflow reservoir may be overfilled, spilling coolant to the ground. No coolant will be recovered.

(7) Abnormal operation 3: Engine is heavily loaded on a hot day, neglected cooling system temperature is above normal, radiator coolant level too low to maintain engine temperature, radiator set pressure exceeded, coolant and steam boil over to reservoir. If engine is not shut off immediately, you're going to be getting a new engine.

@Jrharvey02 is currently at Step (4) headed to Step (5).

Edit: Edited to use terminology marked on Toyota reservoirs, and to clarify the original meaning. No substantial change has been made to original intent.

 

Great write up, thanks! When you say "falls below the pickup tube in the reservoir", is that the tube at the bottom of the reservoir tank? Basically I have just enough coolant in there based on my photo to not be below the pickup tube? Also, when I removed the radiator cap, I noticed there was just a trickle of pink coolant at the very bottom in there. Is this supposed to be filled to the top at all times?

 

Thank you . That’s what I thought . I was referring to the OP’s pictures of the overflow and the inside of his radiator . Then someone suggested that it’s normal for there to be no coolant and it’s all inside the engine .

 

NOT NORMAL. Not for a 5.7L or any other engine cooling system with an overflow reservoir.

You should never even remove the radiator cap unless you suspect that coolant has gotten so low that air is in the radiator.

 

I couldn't see deep inside, but I suspect you've lost enough coolant that you're down to the radiator core.

If you have air at the top of your radiator, you are below the pickup tube in the reservoir. You won't be recovering any coolant from the reservoir even if you now add coolant to the reservoir. Until you top off the radiator, fill the reservoir to "FULL", then start the truck and bring it up to normal operating temperature, you won't recover any coolant from the reservoir. Any small amount of air remaining in the system is "burped" back into the reservoir when the engine warms up, and will be vented there. When the engine cools, the cooling system vacuum will be re-established.

 

If there is an issue with coolant entering the crankcase, this is what could happen. Cold engine sitting - the coolant separates and the oil floats on top, so dipstick can look fine other than maybe a change in oil level. Starting the engine sucks the coolant through oil pickup, then it mixes with the oil and might be visible on the dipstick. Hard to understand if you haven’t drained an engine that got water/coolant in the crankcase. You had already started it so moot point. Pulling the oil filler tube off is easy and would allow you to get a peek inside the engine to check if/how much mustard goop is present.

 

You seem to be very good at copying and pasting Toyota service bulletins and diagnosing problems over the internet on an engine you’ve never owned. Can you please explain what problem I may be having seeing that my coolant is always at the “Full” level, except for a few minutes after starting the truck when it dips slightly below the “low” level (for just a few minutes).
I’m not losing any coolant, never have. I get 14.5mpg and I tow a 25’ boat and 20’ travel trailer all summer long. Never had to add any coolant 85k on the truck.
Please, where does my coolant magically go and how does it magically reappear again if not just inside the block?

 

OK, It's at the shop, so hopefully they know how to do this. But just to get it straight. I just fill the reservoir to cold line, top the radiator off by unscrewing the yellow cap and dumping it in there, run the truck to operating temps, and shut the truck off and i'm all set. Should the level in the radiator, as seen by removing the yellow radiator cap, stay at the top? Or does that level fluctuate a lot like the resevoir tank does?

 

What I've told you here is not from any TSBs or YouTube. It's from personal experience. That's why I understand cooling system operation so well...I was forced to figure them out to fix the problems.

If your coolant reservoir is running between FULL and LOW, then it's operating normally. I have no idea why your coolant level would suddenly fill your reservoir to FULL on a cold startup, but that is not normal. A couple of us have told you that. Are we to assume that your 5.7L has such a big strong water pump that it's popping the radiator set pressure by surging through the radiator? If so, maybe you need a new radiator cap.

If I were you (and I'm not) I would take good advice and find out what's happening with your cooling system. But, if you don't want to ever add coolant, then don't add any coolant. I have observed that coolant is lost slowly simply by evaporation through heat cycles of the engine.

 

You don’t seem to be reading what I’m typing. My coolant is always at the full mark in the overflow reservoir. I’ve never had to add any coolant. The only time it’s low, such as the pic I provided earlier, is when I start the truck from cold and immediately turn it off after 30 seconds or whatever. Let me say this again, I’ve never had to add coolant nor have I ever been low (except that weird few minutes after I start the truck and turn it off suddenly, such as what the OP confirmed he did, too).
What are you suggesting my problem is? Should I call the dealership and tell them I’m not overheating or losing any coolant but a guy on the internet is sure something is wrong with my cooling system?

 

The shop should do all that for you. Just drive the truck normally, and watch the reservoir level. The level should be between "FULL" and "LOW" when cold, and will be above "FULL" when hot. (Sorry, LOW and FULL are the Toyota labels. I've been mixing different OEM labels in my posts.)

My reservoir level right now is about 1" above "LOW" (needs some coolant added). Truck has 5500 miles, and has never had any leaks, no emulsion, and no overheating. Coolant is naturally lost over time.

 

Ok thanks! I guess I should verify they used pink Toyota or the Zerex Asian coolant as well if they didn't flush it? Hopefully this is all just a bad dream and everything is fine!

 

If your coolant overflow reservoir looks like the OP's, which you claimed initially, because he didn't have a problem (see below)...then you have problem. Take it to a dealership, maybe they can explain it to you.

 

It only looks like that when the truck is started and then immediately shut off (just like the OP posted he did), otherwise it’s within a quarter inch of the “Full” line.
Again, should I call the dealership and tell them I’m not overheating nor am I losing coolant but a guy on the internet is sure something is wrong with my cooling system?

 

Where was your level prior to starting? Cold and before start?


Never seen an engine suck rez dry like this if its true and yes I’m open to being wrong. Just never seen it happen on any of my vehicles. Fluid only expands from cold to hot on mine and doesn’t suck in to fill an air void? I’m at sealevel on an Island, as the OP.

 

Oh man, I think you guys can agree, to disagree haha. One last question if someone could be so kind. Is the radiator area that is accessed by removing the yellow cap, supposed to be filled to the top at all times? Or does it fluctuate between full and almost empty, like the reservoir does? As seen in my last pic of original post, it is nearly empty. I just want to know if this is something that should always be full if the issue it corrected. Thanks again.

 

Engine was parked overnight in garage and the level was at “Full” in the overflow container before I started the truck for a few seconds.

 

Ok. It was 1/4” below full. Got my answer. I was wrong and you were right. On the 4.7L the fluid going below the line would mean problems. It never happens unless a problem.

 

You should be able to stick your finger in there and feel liquid. Not necessarily filled to the tip top.

 

Ok thanks, yeah I could feel the tiniest bit in there, maybe the thickness of a pennys worth.

 

Well, I guess I don't need a new engine and I can still drive it lol. They were very polite, but you could tell they thought I was kinda freaking out for no reason haha. Said the condensation is normal for Toyotas and short driving, no concern at all. Pressure tested coolant and dyed it, and it was fine. Oil looked totally normal.

 

You'll sleep better at night.

 

That, sir, is pure unadulterated bullshit that can get others reading this into a lot of expensive trouble. It's probably going to get you into expensive trouble, but you are an adult and allowed to make your own decisions.

Maybe part of the problem that you're not understanding is the radiator HAS TO BE COMPLETELY FULL to the neck when cold, with the reservoir filled to "FULL". It's not the fifties anymore; radiator caps are not removed to check coolant level. Coolant level is checked by looking at the level in the reservoir, which assumes the cooling system was properly filled to start.

Hmmm...Sounds exactly like the advice I gave you early.

 

Nobody mentioned with a blown headgasket, you'll get white smoke out the exhaust pipe and in smells like coolant.

 

Yes, thanks for your help. This was indeed the craziest range of advice i've ever received about anything in my life haha. I appreciate the civilized approach. So, should I unscrew the radiator cap to verify it is completely full now when cold? Or, leave it alone and just keep my eyes on the level in the reservoir tank only?

I have not unscrewed the radiator cap at all since leaving the shop (and taking it for a long drive)

 

John, since you’re adamant that something is wrong with my truck, can you please tell me what I’m supposed to tell the service manager? Should I tell him that I’ve never lost coolant, I’ve never had to add coolant, it remains steady at the Full line, and I’ve never overheated towing a big boat and a moderate camper around Colorado... but this guy on the internet says something is wrong? Really dude, what should I tell Toyota is wrong with my cooling system?
I literally had the same problem as the OP with a 5.7 that I own. I literally posted pictures showing him that it’s normal. Yet, here you are, the owner of 4.6, with no relevant experience with a 5.7, telling me something is wrong with my truck and subsequently the OP’s truck. Yet... the shop verified nothing was wrong with the OP’s cooling system...weird, it’s almost as if you should stick with what you know and that’s clearly not the 5.7.

 

I edited my whole post because I just did a test. The shop said nothing was wrong with the coolant system, but it WAS low, and they topped it off. When I left the shop it was at the full line. I drove on the thruway, came home and it was still at the full line. I just let it cool down for a few hours, and it's at the full line. I started it for 30 seconds, and it's at the full line. No idea what this means. Or that i'd spend the day talking about coolant on the internet.

 

You’re only going to see that coolant reservoir sucked down to nearly empty after the truck has been sitting overnight (completely cooled down).

 

Interesting. Well, for the sake of science I'll wait until tomorrow, and report back!

 

My 4.7 gets the same gunk under the filler cap. The first time I saw it I was really worried. Took longer drives and moisture burns off and it doesn't happen to my truck now. Truck runs very smooth with or without the gunk though.