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Discussion Starter · #1 ·
I need help with identifying the part that is circled in the picture below. And few questions related to it.

As always I turned off my car when I arrived home, but then I heard water boiling noise coming from the engine bay. So popped the hood and noticed a cap was missing.

1. What is the name of the part that is missing its cap so I can order online?
2. After few minutes it stopped boiling, but realized there was no more liquid in there. What is the fluid that I need to get? Is it safe for me to take this to a shop without this fluid in it?

Thanks in advance!

138349
 

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You are missing the cap to your coolant overflow tank.

Water expands as it heats, thus a ''full'' cooling system that is cold will be overfull when hot. The excess goes into that tank. When the system cools, the excess gets sucked out of that tank and back into the radiator. Also, if the coolant gets too hot it will boil out of the radiator - and be captured in the tank. Again, when system cools, it'll get sucked back into the radiator. The fact you heard it boiling/gurgling suggests you were overheating - or at least very nearly overheating. That's not a great sign.

With system COLD, open that cap just below your circle in the pic... the one with get red/white sticker. Look in. If coolant is within 1'' of the top, you're safe to drive.

If not, fill it with distilled water. Then drive it cautiously, being mindful you may have a leak. Repair as needed. Don't fret if it takes a cup or two or three to fill it. DO fret if it takes a quart or more... This indicates you have probably had some sort of loss-of-coolant event, and that's bad.

Do NOT open that red/white cap until engine has been off for at LEAST a full hour. While running, or immediately afterward, there is hot, high pressure coolant in there. Don't have your face directly over the opening. If system is at full temp and you open that - it'll erupt with boing water and a big burst of steam.

Pretty sure this is the part you need:


You might be able to find a suitable replacement from the "Help" section at the auto parts store.

The fact it's missing isn't any particularly big deal and isn't going to hurt anything to drive it a day or two. However - WHY it's missing could point o bigger problems. Maybe it just fell off. But maybe it got BLOWN off by pressurized coolant, perhaps caused by an overheat. Hard to say. You need to be cautious, make sure you have plenty of coolant in the radiator and NOT drive if the temp gage is above the spot it normally operates at.
 

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Oh and also:

The cooling system is supposed to be filled with a 50/50 mix of antifreeze and distilled water. It doesn't need to be exact and it's ok to top it off with distilled water (or even tap water if you're in a pinch) but if the mix doesn't have enough antifreeze you risk it freezing in the winter. The antifreeze also increases the boiling temperature so in really hot conditions, straight water could potentially boil over whereas the correct mix would not.

Unfortunately, there are lots of different types of antifreeze and they are not all compatible with each other. More unfortunately, it can be tough to identify which one is actually in your car - especially considering the age of these cars and the likelihood it's been changed at some point along the way.

If it looks green, this is almost certainly the stuff you need:


If it looks red or dark pink, it's probably this, but no guarantee:


If you've only ever had service at a Toyota/Lexus stealership, you might wanna just buy Toyota antifreeze:


Last, note that some antifreeze comes pre-diluted with distilled water and some doesn't. This will obviously affect how much (if any) distilled water you mix it with...
 

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Discussion Starter · #4 ·
You are missing the cap to your coolant overflow tank.

Water expands as it heats, thus a ''full'' cooling system that is cold will be overfull when hot. The excess goes into that tank. When the system cools, the excess gets sucked out of that tank and back into the radiator. Also, if the coolant gets too hot it will boil out of the radiator - and be captured in the tank. Again, when system cools, it'll get sucked back into the radiator. The fact you heard it boiling/gurgling suggests you were overheating - or at least very nearly overheating. That's not a great sign.

With system COLD, open that cap just below your circle in the pic... the one with get red/white sticker. Look in. If coolant is within 1'' of the top, you're safe to drive.

If not, fill it with distilled water. Then drive it cautiously, being mindful you may have a leak. Repair as needed. Don't fret if it takes a cup or two or three to fill it. DO fret if it takes a quart or more... This indicates you have probably had some sort of loss-of-coolant event, and that's bad.

Do NOT open that red/white cap until engine has been off for at LEAST a full hour. While running, or immediately afterward, there is hot, high pressure coolant in there. Don't have your face directly over the opening. If system is at full temp and you open that - it'll erupt with boing water and a big burst of steam.

Pretty sure this is the part you need:


You might be able to find a suitable replacement from the "Help" section at the auto parts store.

The fact it's missing isn't any particularly big deal and isn't going to hurt anything to drive it a day or two. However - WHY it's missing could point o bigger problems. Maybe it just fell off. But maybe it got BLOWN off by pressurized coolant, perhaps caused by an overheat. Hard to say. You need to be cautious, make sure you have plenty of coolant in the radiator and NOT drive if the temp gage is above the spot it normally operates at.
Thank you so much for this mate! Extremely helpful!!
 

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Discussion Starter · #5 ·
You are missing the cap to your coolant overflow tank.

Water expands as it heats, thus a ''full'' cooling system that is cold will be overfull when hot. The excess goes into that tank. When the system cools, the excess gets sucked out of that tank and back into the radiator. Also, if the coolant gets too hot it will boil out of the radiator - and be captured in the tank. Again, when system cools, it'll get sucked back into the radiator. The fact you heard it boiling/gurgling suggests you were overheating - or at least very nearly overheating. That's not a great sign.

With system COLD, open that cap just below your circle in the pic... the one with get red/white sticker. Look in. If coolant is within 1'' of the top, you're safe to drive.

If not, fill it with distilled water. Then drive it cautiously, being mindful you may have a leak. Repair as needed. Don't fret if it takes a cup or two or three to fill it. DO fret if it takes a quart or more... This indicates you have probably had some sort of loss-of-coolant event, and that's bad.

Do NOT open that red/white cap until engine has been off for at LEAST a full hour. While running, or immediately afterward, there is hot, high pressure coolant in there. Don't have your face directly over the opening. If system is at full temp and you open that - it'll erupt with boing water and a big burst of steam.

Pretty sure this is the part you need:


You might be able to find a suitable replacement from the "Help" section at the auto parts store.

The fact it's missing isn't any particularly big deal and isn't going to hurt anything to drive it a day or two. However - WHY it's missing could point o bigger problems. Maybe it just fell off. But maybe it got BLOWN off by pressurized coolant, perhaps caused by an overheat. Hard to say. You need to be cautious, make sure you have plenty of coolant in the radiator and NOT drive if the temp gage is above the spot it normally operates at.
So I realized that it's not just the cap missing, but the hose attached to it is also missing. What is on the other side of the hose? Where does it connect to?

138350
 

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The hose on the lid of the expansion tank runs down the rear side of the radiator/fan shroud and doesn't connect to anything. This way, a boil-over that fills the expansion tank will be vented straight to the ground, rather than all over your engine.

A second hose runs from the top of the radiator, just below the cap with the Red/White sticker, to the bottom of the expansion tank.
 
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