Cooling system boiling, no overheat

Status
Not open for further replies.
Joined
Oct 11, 2002
Messages
22,183
Location
Colorado Springs
My Corolla had a strange one yesterday. I drove up into the mountains and the initial road out of town, US 24, has a 7% grade. Pretty steep. Done this drive a thousand times without issue. I pulled into a gas station to get some coffee. Came back out, sat in my car, and immediately heard a bubbling/gurgling sound. First thing I thought was cooling system. Popped the hood and the overflow was to the top and some coolant was blowing out the overflow tube. I put the heater on, started the car, and the level came back down. I continued on my journey and didn't have any other issues except the level in the overflow continues to fluctuate a lot more than it ever has and came close to overflowing again. There is no signs of overheating at all!

So I bought a new radiator cap this morning and will see if that is the issue. If not, I think it's head gasket time.
frown.gif


The only other weird symptom it's had lately is, in the morning when I start it, if I put the heat on, I can hear coolant rushing into the heater core which indicates air is getting in the system. It's done that for 2 years now. I tried burping the system many times with a Lisle funnel, and the air sound always comes back.
 
Originally Posted By: bullwinkle
Might be time to get a combustion gas tester and see if compression is getting into the coolant. Before it gets too hot and does more damage.


+ 1
 
Originally Posted By: Drew99GT
My Corolla had a strange one yesterday. I drove up into the mountains and the initial road out of town, US 24, has a 7% grade. Pretty steep. Done this drive a thousand times without issue. I pulled into a gas station to get some coffee. Came back out, sat in my car, and immediately heard a bubbling/gurgling sound. First thing I thought was cooling system. Popped the hood and the overflow was to the top and some coolant was blowing out the overflow tube. I put the heater on, started the car, and the level came back down. I continued on my journey and didn't have any other issues except the level in the overflow continues to fluctuate a lot more than it ever has and came close to overflowing again. There is no signs of overheating at all!

So I bought a new radiator cap this morning and will see if that is the issue. If not, I think it's head gasket time.
frown.gif


The only other weird symptom it's had lately is, in the morning when I start it, if I put the heat on, I can hear coolant rushing into the heater core which indicates air is getting in the system. It's done that for 2 years now. I tried burping the system many times with a Lisle funnel, and the air sound always comes back.


Is coolant being consumed? That is really weird that you can bleed the system of air but it comes right back. I would think that if the HG was the culprit and you were driving it for two years it would have gotten worse or more obvious by now.

I would try to find an airlift or a shop with one and use it to bleed the system. The block tester is a very simple way to rule out the HG and cheaper that the former option if you rent it. I have a feeling it is not the HG but I am no pro mechanic or Toyota expert.
 
Sounds like a classic case of a coolant system incapable of recovery. System pushes coolant out as it expands, and then ends up sucking in air instead of drawing coolant back in.

The SLIGHTEST problem with either the radiator cap or tube going to your overflow tank can cause this. Won't leak a drop of coolant, but will allow for air to get in under vacuum, eliminating the ability of the system to draw coolant back in as it contracts.

Gurgling and bubbling sounds after shutdown, with no overheating while operating? Yup. Just dealt with this problem this week on one of my trucks. One month ago I dealt with this problem on a boat.
 
Originally Posted By: DoubleWasp
Sounds like a classic case of a coolant system incapable of recovery. System pushes coolant out as it expands, and then ends up sucking in air instead of drawing coolant back in.

The SLIGHTEST problem with either the radiator cap or tube going to your overflow tank can cause this. Won't leak a drop of coolant, but will allow for air to get in under vacuum, eliminating the ability of the system to draw coolant back in as it contracts.

Gurgling and bubbling sounds after shutdown, with no overheating while operating? Yup. Just dealt with this problem this week on one of my trucks. One month ago I dealt with this problem on a boat.



Good recommendation. Does the reservoir tube fit snugly onto the radiator filler neck?
 
Originally Posted By: DoubleWasp
Sounds like a classic case of a coolant system incapable of recovery. System pushes coolant out as it expands, and then ends up sucking in air instead of drawing coolant back in.

The SLIGHTEST problem with either the radiator cap or tube going to your overflow tank can cause this. Won't leak a drop of coolant, but will allow for air to get in under vacuum, eliminating the ability of the system to draw coolant back in as it contracts.

Gurgling and bubbling sounds after shutdown, with no overheating while operating? Yup. Just dealt with this problem this week on one of my trucks. One month ago I dealt with this problem on a boat.


That would explain the boiling without overheating too, right? Without the ability to maintain system pressure, the boiling point of the coolant is reduced.
 
It was a bad cap. Weird; the old cap was from Oreilly Auto, was about 5 years old I think. Never had a radiator cap go bad! The spring felt stiff on it. But with a new cap, the level sits exactly where it should in the overflow now. Hopefully that solves the heater gurgling!
 
I don't remember where I heard it (maybe it was the Subaru techs), but it was recommended to me on the old green coolant that you change the coolant every 2 years or 30k, and always replace the thermostat and radiator cap when you change the coolant to prevent things like this from happening. Newer cars don't need the coolant every 30k, but to me it's cheap insurance to change the thermostat and radiator cap at the same time regardless of your interval. When I changed the coolant on my Fusion I did the thermostat, only added $30 to the total and now there's nothing to worry about. Would the original have continued to chug along for another 50-100k? Maybe, but now there are no questions until the next coolant change.
 
Originally Posted By: SubieRubyRoo
I don't remember where I heard it (maybe it was the Subaru techs), but it was recommended to me on the old green coolant that you change the coolant every 2 years or 30k, and always replace the thermostat and radiator cap when you change the coolant to prevent things like this from happening.


Upsell alert!

New thermostat and rad cap every two years? My eyes would have rolled 360 degrees!
 
Originally Posted By: Drew99GT
It was a bad cap. Weird; the old cap was from Oreilly Auto, was about 5 years old I think. Never had a radiator cap go bad! The spring felt stiff on it. But with a new cap, the level sits exactly where it should in the overflow now. Hopefully that solves the heater gurgling!


Any updates? Still fixed?
 
Status
Not open for further replies.
Back
Top