Swollen Coolant Hose - Strange Symptoms (1 Viewer)

[94SRUNNER]

Correct! Just as I've post many of times. It works, and is only sure method!

Provided no air bubble blockage. Which I've only seen bubble blockage in heater core(s). Which you can easily tell as Water temp gauge reads normal (3 o'clock), but cabin heater does not blow very hot as it should. I hit the brakes hard at ~30 MPH and I hear gurgling sound as bubble dislodged, than heater blows hot. May need to top rad again.. This only happens sometime, when I blow out heater cores. But low coolant will not reach heater cores at all, or until very hot (expansion). This too result in no or low cabin heat.

I can't say you don't have other issue that may needing attention. But over night cool down, is best way to top and remove air in a properly serviced coolant system.

What happens is, by parking front end high. The radiator top become high point. Air bubble will form at high point as coolant cools and contracts. But if you open the cap before full cool down, you loose vacuum of contraction. The contraction vacuum sucks coolant from reservoir. But fail to do so efficiently if air bubble at top of radiator (goose neck of cap). Fails if reservoir hose clogged. Fails if reservoir hose end is not submerged in coolant (sucks air)

A stuck closed thermostat, will result in overheating.
A weak thermostat will result in not reaching operating temp.
A very low coolant system will result in overheating and blowing engine.
Weak cap will result in runn cool.
Stuck cap will result in over pressurizing and likely overheating.
Clogged radiator fins (washe the fins( result in running hot even overheating.

Radiator fins need cleaning! Alert Alert Alert

I've a 06LC w/192K I just bought. In reading history I found PO complained of engine temp raising when both front and rear AC on. Toyota Dealership diagnosed with clogged radiator fins. Recommended new OEM radiator, $600 for the US spec Radaitor plus coolant and labor. They should have added...

forum.ih8mud.com

Sound advice as usual

 

[flintknapper]

It sounds like you may still have air in the system. When I did some work last month on my coolant system I first bled the system without the radiator cap and the front end elevated, but was not able to get all of the air out of the system. The following morning I used the coolant system bleeding funnel (purchased on Amazon and pictured below) that attaches to the radiator to bleed the system. This allowed me to get the large majority of the air out of the system. One other note, when you installed the thermostat, was the jiggle valve oriented in the correct position, i.e. at 12 o'clock?

View attachment 2746463

^^^^

I find it a very useful tool also.

 

[mitchclem]

All good advice, much appreciated. I parked uphill overnight and topped up the coolant in the rad this morning. I also verified that the pathway to the reservoir was clear with no obstruction, and coolant was to the "low" line in the reservoir. After driving for about an hour today, I pulled over to check on things and the coolant level in the reservoir had not budged. I get full heat from the climate control and my temp gauge still hasn't wavered from 3 o'clock. Is there anything this could be other than my radiator cap?

 

[flintknapper]

All good advice, much appreciated. I parked uphill overnight and topped up the coolant in the rad this morning. I also verified that the pathway to the reservoir was clear with no obstruction, and coolant was to the "low" line in the reservoir. After driving for about an hour today, I pulled over to check on things and the coolant level in the reservoir had not budged. I get full heat from the climate control and my temp gauge still hasn't wavered from 3 o'clock. Is there anything this could be other than my radiator cap?

Yes

The cap and/or hoses on your overflow reservoir should be checked.

The hose that leads from the nipple on your radiator to the cap on the reservoir is easily checked by blowing through it. That hose connects to the cap on the reservoir which has another hose that extends down to the bottom of the reservoir.

It is THAT hose that can deteriorate and plug the hole in the cap. So take both hoses off and check their condition. Also inspect the cap and see that is not clogged/plugged.

The cap also has a small 'void' cast in it to allow overflow of the reservoir should it become filled. On an 80 series there is a third hose that does this, but the 100 series does away with that.

Typically, IF you are not seeing fluctuation in the fluid level of the reservoir *radiator FULL* then it will be the radiator 'cap' at fault, but the path to the overflow reservoir *starting at the nipple on the radiator* must also be unobstructed. So its worth checking.

As you are aware....when engine coolant heats up... it expands slightly. So....provided the system is at full capacity *and no leaks* then it is normal for some amount to be expelled from the radiator to the overflow reservoir, that is the purpose of it to begin with.

Later, when the engine is shut down and the system cools, the coolant contracts. This creates a vacuum on the system *if there are not any leaks* and an amount of coolant from the reservoir will be drawn back into the radiator until the vacuum is relieved. Again, a normal and desirable function. This action keeps the radiator full and relatively free of air.

 

[mitchclem]

Yes

The cap and/or hoses on your overflow reservoir should be checked.

The hose that leads from the nipple on your radiator to the cap on the reservoir is easily checked by blowing through it. That hose connects to the cap on the reservoir which has another hose that extends down to the bottom of the reservoir.

It is THAT hose that can deteriorate and plug the hole in the cap. So take both hoses off and check their condition. Also inspect the cap and see that is not clogged/plugged.

The cap also has a small 'void' cast in it to allow overflow of the reservoir should it become filled. On an 80 series there is a third hose that does this, but the 100 series does away with that.

Typically, IF you are not seeing fluctuation in the fluid level of the reservoir *radiator FULL* then it will be the radiator 'cap' at fault, but the path to the overflow reservoir *starting at the nipple on the radiator* must also be unobstructed. So its worth checking.

As you are aware....when engine coolant heats up... it expands slightly. So....provided the system is at full capacity *and no leaks* then it is normal for some amount to be expelled from the radiator to the overflow reservoir, that is the purpose of it to begin with.

Later, when the engine is shut down and the system cools, the coolant contracts. This creates a vacuum on the system *if there are not any leaks* and an amount of coolant from the reservoir will be drawn back into the radiator until the vacuum is relieved. Again, a normal and desirable function. This action keeps the radiator full and relatively free of air.

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View attachment 2747926

I inspected both hoses and the reservoir cap this morning, clean as a whistle, no obstruction. I will continue to park uphill and burp the system each morning and replace the rad cap on Tuesday when my local dealer opens. Thanks for the awesome write-up and visuals. I'll update as the situation progresses.