Coolant bubbling in overflow tank

My wife and I just recently picked up a new to us 2008 Sequoia with the 5.7L 2 months ago. We drove it all the way from Florida (in law) -> Texas (parents) -> Arizona (home) without any hiccups. We've been driving it around town and about a month ago, something told me to check the coolant level in the actual radiator even though the overflow tank was sufficient. Sure enough, it was low half a gallon. So I topped it with OEM Toyota coolant. Fast forward to today, we (the family) was with me and I needed to stop at a junk yard for an alternator on my daily beater. The family stayed in the Sequoia with a/c on. When I came back out, I saw coolant on the ground. I popped the hood and coolant was just boiling in the overflow tank causing it to boil and drip to the ground. I shut off the engine and waited for it to cool and proceeded home. Temp gauge was fine going home.

Fan works fine. I'm thinking I either have an air bubble in the system or bad thermostat?

 

check your radiator cap the valve could be bad.

 

⬆ Try that first, cheap and easy.

 

For sure the radiator cap first if it still does it then maybe air got in the rad when you added the coolant .

 

Check the oil for contamination. If it's milky, you have a blown head gasket and the compression is being released through the radiator. You should also check for a sweet smell at the exhaust, and have a leak down test performed on the cooling system. If the engine is hot enough to boil the coolant, something is very wrong. It could be as simple as a bad radiator cap, but it needs to be fixed fairly soon or it could cause engine damage.

 

Have the cap tested. Sounds like a bad one to me.

 

Check your coolant also. Maybe diluted or old ... Does the color look rusty?

 

Miles on car now? Before you go buying a new cap, see if you do have bubbles in the system. Get the front end lifted, use a jack, roll up jack or even the curb if its tall enough to give you slope. This allows for the radiator cap be on the high end air will naturally flow towards the opening.

Start the car, remove the radiator cap and let it come up to temp so that the thermostat valve opens up. As its idling you should see the coolant move differently when the thermostat opens up (if the flow rate never changed, you might have a stuck thermostat). As its idling you may see some bubbles come up out of the hole. keep on running the car till you dont see any more bubbles come out, maybe even have someone tap the throttle couple times to make sure no more bubbles. Hope that this was the case, top off coolant and reservoir.

If you dont see any bubbles come out, get a new radiator cap, top off coolant and reservoir and put car back level and let it sit to see if you get the overheating/overflow of coolant. If you don't, great, hopfully its fixed. If you do, my guess would be you have a bad water pump. Over the years, esp if coolant wasnt maintained/changed, it becomes corrosive and the blades get eaten up/falls off. Some fins would still be on there so while driving you have circulation and car can cool down enough, but at idle, the missing fins doesnt allow for good circulation thus causing the coolant to overheat/boil over. The fins can also have caused blockage in the radiator through some of the channels thus restricting flow.

To see if you have flow restriction in the radiator, get one of them laser pointer thermostat, have everything closed off and engine idling, shoot at different areas of the radiator. You will have some significant temp differences if any of the channels get blocked. Sometimes you can stick a hose in the radiator and blast it in the opposite direction of the flow and pieces can come out unclogging it. put it back together, get it up to temp again and see if hotspots still exist.

I've dealt with many cars in the past overheating and have experienced just about every issue. I doubt you have any blockage in your lines since it still cools during normal driving. Hope this helps, good luck and feel free to ask any other questions.

 

You may be right, prior to purchasing, I did notice dried coolant around the cap area.

I think this may be the culprit.

No oil contamination. I also did a recent oil change and it was not milky either.

It's bright pink. New looking actually.

I'm currently at 236,500 miles. I poked my head around the water pump area. I don't see any signs of a failing fan, like coolant leaks around the area or around the escape hole.

Since we travel long distances and especially through rough areas like deserts and long stretches without any cellular service when we commute back and forth, I'm going to go ahead and replace: radiator (denso), cap (oem), upper and lower hoses (Gates), and thermostat (oem).

Now as far as coolant, I'm tired of paying $3x for toyota coolant. I feel like its a bit much. Is this one good? Or what do you recommend?
https://www.pepboys.com/oem-antifre...-lexus-scion-with-pink-coolant/product/879899

 

Consider the water pump. I had a situation long ago, I lived in a desert area for the better part of 6 years and my water pump was the culprit as it had burst according to the stealership. For me there was no coolant in the fan, but there was coolant around the radiator cap, splattered on the hood and caked on the skid plate. Additionally my radiator cap just failed a few months ago as well and I have a chunk missing, but I think the stealership swapped it out just my .02, cuz I checked before and after and it was gone. I'm at 220K so not far away from you.

 

https://shop.advanceautoparts.com/p/prestone-toyota-vehicle-extended-life-50-50-antifreeze-coolant-1-gallon-af6200/11842065-p?product_channel=local&store=1328&adtype=pla&product_channel=local&store_code=1328&gclid=EAIaIQobChMIxciB3KT35wIVB7zACh2b2QzdEAQYASABEgI6a_D_BwE&gclsrc=aw.ds

I use this $18

 

water pump doesnt have to leak, ive seen the blades on waterpump corrode off

 

Just as everyone suspected, it ended up being the cap! Thanks guys! Still awaiting all parts from rockauto to come in to refresh cooling system

 

FYI: I use this https://www.autozone.com/antifreeze...d-pink-antifreeze-and-coolant-1gal/720595_0_0

 

HI ALL! I found this forum searching for coolant issues. I use to be on Tundra Solutions. I do not drive my truck a lot, about 50 miles per week average. Recently I changed the oil, filter, spark plugs and front brake pads, check all fuel levels.
Twice after this on short trips, I smell anti-freeze but I did not fine any leaks, had to had about a cup full of coolant then on the third short trip I found coolant on the front of the radiator and a little on the floor. Check and I could not locate any leaks. Check the trans and oil and they are good. I decided since the last time I replace the cap and thermostat was at 126,000 miles. I replaced the cap, thermostat, gasket and the radiator, drain the anti-freeze and refill with Peak Asain red/pink 50/50 anti-freeze. Hoses are good, both belts are good. Took a short trip and when I pulled into my driveway I heard a clanging noise and the check engine light was on so I shut the engine it off. When I raised the hood I had coolant all over the front of the radiator and on the garage floor, the over flow was filled with coolant and leaking out of the cover. The radiator cover seems okay. I waited till it cooled and check, I could not find any leaks any where. I decided after some research that I would replace the water pump, time belt and the serpentine belt. In the process of doing this now. Has any one experience this? Any clues/ideas of what I am looking at? Any help is appreciated. My truck is now at 150,000 miles. I really don't want to buy a new truck. I am retired and the income is fixed.

 

I would go get a radiator/cooling system pressure tester and pressure test the system. You can do the loan-a-tool thing at most chain auto parts stores. You pay for it up front and they give you all your money back when you bring it back. You could also put it on a credit card.

Hook up the tester and pressurize the system. I would think the leak you described would show up pretty easy.