Coolant Bottle Empty

I noticed my coolant bottle was empty so I filled it. It seems to empty after about 10 miles of driving. I figured the leak would be easier to find if I let more coolant spill out, so I kept refilling the bottle. The inside of the engine bay is splattered with pink spray all over, but the leak did not become obvious. I think its in the front and the fan is spraying it everywhere. Every time I've checked the radiator when the engine is cold there has been coolant visible at the top and the fins in the radiator looked submerged. I have gone through 2 gals of coolant and stopped filling the bottle since the level in the radiator seemed stable. Now the level in the radiator is lower.

How should I find the leak?

 

I think you have a leak...

The radiators like to fail after they're 10 - 20 years old. If the plastic is brown instead of black you have a winner! Also, check the radiator cap. One time I found that the silly little hose that connects the radiator to the expansion tank was the leak!

There's a dozen or so coolant hoses connected seeming everywhere, any on of which could be the source of your leak.

And finally...the water pump. When was your timing belt (and water pump) last replaced?

You might want to invest in a pressure tester to hasten your investigation.

$105 OEMTOOLS 27068 Universal Cooling System Pressure Test Kit, Automotive Radiator Pressure Tester for Coolant System, Diagnostic Tool for Radiator and Reservoir Leaks, Includes Adapters And Case

https://www.amazon.com/OEMTOOLS-270.../dp/B071W9B31L?smid=A2W86Q8280F2Q3&gQT=1&th=1

 

If you're spraying all over the inside of the engine bay, it sounds like your radiator cap is fucked. Might want to address that. They go bad, you know.

 

I had an issue with my 3.4 building a ton of pressure in the cooling system. It was not flowing back and forth through the overflow bottle, just building a ton of pressure and spraying from around the hoses and seams. I replaced the radiator cap with a new one but it didn't change anything. It wasn't until I went to the junk yard and found 3 caps and tried them all where I found one that lets the pressure flow into the reservoir and not build up all that pressure within the system

 

Thanks for advice! I'm going to bite the bullet on a pressure testing kit and a radiator cap; if the pressure tester doesn't reveal the leak I'll assume its the cap. If its not the cap, ill have an extra cap for when it does start leaking. I didn't know the caps went bad. Can't find a part number for denso radiator caps, do the denso radiators come with caps?

The water pump and timing belt were done last august. Thats when my starter broke... I'm also worried I damaged the radiator leaning on it while pulling the intake to access the starter. The truck hasn't been used much recently, only a few hundred miles since then.

The pink HOAT coolant is anti-corrosive right? So I shouldn't worry about cleaning it off of everything in the engine bay?

 

16401-20353 (NOTE: the old part# ended in -72090), it's only $13 on pickup from my local dealer (if I order it using that Toyota Official Parts site link).

 

Oh, and the directional spray suggests it is, in fact, the radiator cap. We have some pics on here of someone who actually had the bottom half of their cap fall out. It's spring loaded underneath the cap. Not asking you to be a CSI detective here and look at blood spatter, but spatter directionality and voids will tell you a lot about where stuff is coming from. Just know: Liquid will ricochet off stuff, so ...

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That is an understatement. I thought letting it spray more would make the source more obvious but there is so much spray everywhere its really been puzzling to me. It seems to be hitting that refrigerant hose and the oil fill spout a lot. The hood is getting a lot of spray too.

My cap seems relatively clean, no obvious collection of coolant. I didn't realize it was a pressure release and there is no spout/outlet. There is no puddle in the bottom of the engine bay either. I definitely think the leak is somewhere in the top front/ near the radiator. Cap is $30 from my dealership. I'll see if that works then buy a pressure testing kit.

You guys on this forum are a life saver!

 

Yeah, it definitely doesn't look like it's coming from the cap, I agree.

A few places to look at:

• Check your larger hoses for possible pinhole leaks.
• Radiators are a slab of metal fins with plastic caps, and thin liquid filled tubes throughout; they tend to leak at the base of the plastic cap, and at those tubes, but sometimes it doesn't show up until you're at-temp, and revving the engine.
• There's a small coolant hose that passes thru the bottom of the throttle body, check it carefully too
• There's a bolt hidden behind the smaller tube in the pic, about 1-2" up from where the overflow tube meets the overflow bottle. I think it's a 10mm. Pop it out, push the fan shroud forward; any fluid on the back of it? Repeat on the other side, there's a similar bolt there.
• Look for voids, places where there's no coolant spray, and see if you can figure out an angle fluid could spray and leave a void in that spot. Look for puddling, pink coolant usually leaves crystalization when it puddles.

Really, people should be proactively changing their radiator at the same time as the timing belt, if you ask me. They're usually good for 125k-150k miles, but I wouldn't trust them much past 125k. Especially not when you consider you can destroy your transmission if the trans cooler line passing thru the bottom of the radiator leaks. Your coolant needs to be changed every 100k if you're using the correct pink SLLC coolant Toyota urges you to use, so why not do the radiator and timing belt at the same time, y'know?

But if you can track down roundabout where the coolant is coming from, you'll answer your questions. Is it above, behind, left or right of the radiator? Or is it possibly one of the hoses, or is it maybe seeping from one of the metal housings/bibs where the coolant hoses clamp onto?

 

Shifty' said, "Oh, and the directional spray suggests it is, in fact, the radiator cap. We have some pics on here of someone who actually had the bottom half of their cap fall out. It's spring loaded underneath the cap."

That was me and my issue.
Installed a new Denso radiator and cap in the winter, was never burped 100%. Never had any issues in the cooler weather. But, when I was driving in the mountains at115 degrees in started spraying when hitting the fan.

Resolved the issue with a new TRD cap and a good "Burp".... no problems since. Link to photos below

https://www.tundras.com/threads/i-could-use-some-help-sourcing-a-coolant-leak.145284/