Overheating/coolant loss

Back on here again because I am lost. I’ve searched all the threads about this and looked through the “common” areas where coolant leaks appear but can’t find anything. I was in traffic and noticed my truck was overheating. Turned it off and was able to get it home because when I was moving temp gauge was going down. Checked the reservoir and I was low. Filled it up with some 50/50 blend zerex red. 2 days later same thing, lost all the coolant in my reservoir. I’m ready to swap out the radiator only because I don’t know last time it was changed. Any last suggestion before I do that? Here’s a photo of the only leak I could find which I couldn’t trace back.

 

How many miles are you at?

Add a photo of the bottom of your radiator cap, a photo of your engine bay so we can see the radiator( see how brown it is)

remove the skid plate and add photo from around the pulleys, the more photos the better

 

It's potentially the radiator cap. Let's see a picture of the top of it, and the inside of the cap, to make sure the springloaded internals are still there.

Otherwise, it's the notorious oil cooler o-ring leak, given its position just above the oil filter.

Meanwhile, bad idea using red coolant, not only is it wrong (pink long-life is what Toyota wants), but someone has clearly put the wrong color coolant in the truck, or used "universal" coolant, which is a gimmick. You've clearly got yellow/green coolant in there, our trucks are supposed to use pink long-life.

Unfortunately, when you mix colors like that, you can end up with serious blockages. Like, this exact type of buildup, inside the throttle body bypass, the lines to the oil cooler, clogging everything up to the oil cooler, clogging the internals of the oil cooler, completely clogging cooling hoses, one radiator hose, another radiator hose. This was the consistency of it. His previous owner was a dumbass and didn't understand you can't mix coolants and there's no such thing as "universal" coolant. Use the coolant Toyota recommends.


I don't think blockages are your issue here. I suspect your cap is potentially dead, or that o-ring is fucked, but know that your cap actually prevents overheating. But beyond that, you may have a bubble.

You really should flush whatever coolant is in there out, using the two drain blocks (under the exhaust manifolds), from the radiator, fill with water, flush again, then install the correct coolant.

Yell at the person who put the wrong coolant in your vehicle. And if it's a mechanic, don't go back to that mechanic, they clearly don't know WTF they're doing, or are too f'n lazy to look up what the manufacturer's recommendations are (or they think they know better, either way it's a bad situation).

 

Thanks for the help. This weekend I’ll flush it and put the proper coolant in. Here’s the photos of the cap I’m not too sure what to look for on this.

 

Well, for one, you're low on fluid. Just curious, when was the last time the fluid was changed? And was the truck properly burped when the fluid was changed? Air bubbles in the system (and low coolant) can both cause overheats. Your coolant bottle is marked with coolant levels for 'hot' and 'cold' and you should be on the line in either state, if not, you're low on coolant. But you can't use that as your only way of knowing, because again, if air gets in the system ... or someone does something stupid, like install the thermostat incorrectly (jiggle valve needs to be pointing straight up, 12 o'clock), air can cause blockages which prevent coolant flow.

Important to remember: Heat = expansion. Steam = expansion. Expansion causes pressure. Pressure needs somewhere to go, it has to blow off somewhere. So you want no air in the system, so no way to make steam, and you need a working blow-off valve (which is in the radiator cap) to allow for expansion of the fluid when it heats up to high, nearly-boiling temps. The cap is rated to open/release at a certain PSI of pressure.

Cap-wise, it visually looks fine, although clearly different from OEM. You're basically looking to make sure this springloaded bit is intact (see arrow, 1st pic). When the coolant heats up and the pressure in the sealed coolant system increases, that springloaded part opens, allowing coolant to pass out of the little tube and into the overflow, reducing the pressure on the system. Sometimes generic, off-brand, cheap Amazon/eBay shit caps don't work correctly, the spring will seize up, etc. But more often than not, when people are overheating, the spring mechanism exploded like you see in the 2nd picture with an OEM cap, and the OEM cap part number. When that springloaded end part blows up, or if the spring is stuck, coolant can't flow in/out of the overflow correctly, so the pressure builds up until it finds any way out it can get!

​

 

Not sure last time it was changed. I bought this truck with 100k miles on it and I just went over 140k so newer to me. I took it to toyota right when I bought it and they did the full 120k service which they said they did full fluid changes and checked it out.

For now this weekend I’ll flush the coolant and burp it properly. Is this the proper one?

 

Coolant is due for exchange in our 2005-2006 pickups, with the 1st change due at 100k miles or 10yr, and after that they say every 5 years or 60k miles if you use pink long-life. Other coolants, yellow/green, and red, whatever (basially anything non-pink) usually have a lifespan around 30,000 miles if memory serves. So-called "universal" coolants, some boast numbers as high as 150k miles, which is total and utter bullshit. The whole premise of "universal" coolants is bullshit, but I'm just being harsh because it's a pet peeve of mine.

The main difference between red and pink, just so you know, is purely the lifespan. Pink is good for more miles, and it's what Toyota wants you to use with our later-year 1st gen engines.

That Toyota SLLC coolant you showed a pic of is fine. So is Pentosin Pentofrost A4, which is about the same price.

You'll need roughly 3.5 gallons. Drain the radiator using the petcock. Drain at the oil cooler. Open both block drains. Close drains, fill it up with water while running (with the heater on full blast) it to dilute any yellow/green still in there. Then drain again. Fill it up with the SLLC pink, but it's recommended you have the nose of the truck up higher than the rear during fill, run the heat at full blast so the heater core is open, and use a burping funnel, like this: https://www.tundras.com/threads/wha...-gen-tundra-today.2558/page-2446#post-3999674

@Nimitz_ and @BroHon and @bmf4069 can all probably give you lots of advice on the burping funnel and process. It's something I actually need to do myself in the near future.

 

Thanks I’ll give that a go this weekend.

 

You got it brotha. I'd have AT LEAST 4 gal on hand. I used that on just a rad replacement.

 

I took some pictures and the radiator looks to be good/no leaks. So I will stick with my plan of draining/flushing refilling with proper coolant. Before I do though where exactly is the o ring that you were talking about? I took some photos but my engine has a lot of old oil on it so hard to tell for me.

 

The o-ring shifty mentioned is the piece the oil filter screw to. That's the oil cooler. Another well known coolant leak spot is the crossover tube under the intake manifold.



Can you tell if there's any coolant in the valley or on the back of the motor?

 

Actually, I'm looking at the passenger side and I see something disconcerting. I'm pointing out the timing belt tensioner, which frankly looks like a dick n balls, so you have a frame of reference. Alterator is sitting under the arrow.

So, I clearly see something is leaking, pretty substantially, down the front of the block. I can't tell if this is coolant or oil leaking, you likely either have the water pump leaking, or a cam seal, is my guess.

If you're overheating, based on the fact you clearly don't have enough coolant in the radiator, and you're overheating, I'm inclined to say "water pump is leaking/failed".

Whoever did the timing belt last should've replaced the water pump, thermostat, pulleys, and that tensioner, ideally using the Aisin kit, since aftermarket belts, even the good brands, often don't last the entire OEM interval. We recommend the Aisin kit, it contains OEM parts.

This could be very serious, if coolant is leaking onto the timing belt, it will compromise the belt, and the belt will fail prematurely. This leaking you found, this overheating, may actually be a blessing in disguise. If you were smart, you'd loosen the timing cover bolts on that side enough to peek in on things, and verify the timing belt isn't already fraying/torn/warped. But needless to say, you're definitely low on coolant, and I personally wouldn't replace the coolant without figuring out what this leak is, if the water pump failed, you may as well get the timing kit and overhaul.

​

 

And as for the leak of the oil cooler we were talking about.

This video shows when the oil portion of that leaks. Basically, the round part of your engine where the oil filter screws onto it, the threaded base, it has a coolant line attached, and oil passing through it. It sits above the crossmember, and can leak oil or coolant onto the crossmember up front, specifically on the driver's side, but it looks like the passenger side is where your problem is, so I doubt this is it.

Still, I'll post the videos, one that shows when the oil filtering housing is leaking, diagnostics, and the 2nd video is the repair.Watching the videos you'll see how coolant lines are attached. Actually, in the still shot on the 2nd video, that upturned hose bib is a coolant line.

https://www.youtube.com/watch?v=s_5uryZfPKE

https://www.youtube.com/watch?v=eeWAQzcqhPo​

 

The back of the engine looks to be pretty clean to my eyes. I’ll try and get some photos later after work

 

Yeah I’ve noticed that before and I’m pretty positive it’s oil. The timing belt/water pump was changed 20k miles ago along with cam shaft and crank shaft seals being replaced because they were leaking. I asked the tech if he used OEM parts which I was told yes but I guess he could be lying.

 

That oil or coolant is shiny, which means it's fresh. Something's not right under there, but you won't know what's wrong unless that timing cover comes off.
You may be able to get under there with a flashlight, and see where the shinyness is coming down from.

 

Here’s some photos by the dipstick where I can see some fresh oil. And one other by the timing belt

 

Welp, valve covers are definitely leaking. Looks like someone didn't seal the corners between the valve cover and cam tower properly.