Engine Never ending bubbles at radiator cap opening??

beeduckworth · Sep 21, 2023

Car runs great. Idles well power is nice. I completely fully rebuilt the motor down to bearings and rings. Yes I installed head gaskets in with holes in rear. Car runs at 195 when idling even for hours. Never changes. When driving on the freeway I get to 225 degrees. Seems a little hot. I will attach a photo of the bubbles. What can add bubbles to cooling system.

Car is already warm and bubbles continuously come up.

I used a hydrocarbon blue fluid to yellow fluid tester. Fluid doesn't change. I used an extended coolant funnel and covered it with cardboard with a hole in it and tested every 5 minutes for a half hour.

Where can these bubbles be coming from. I see no oil in water or water in oil. I'm confused....

Edit: also wanted to mention I put 130 psi of air pressure in each cylinder at top dead center and never saw one bubbles come up.

Video 1

Video 2

AeroCoupe · Sep 22, 2023

How long ago was the rebuild and are you having to add any fluid?

beeduckworth · Sep 22, 2023

AeroCoupe said:
How long ago was the rebuild and are you having to add any

3 months ago, and not exactly sure. I'm going to mark my overflow and check it.

AeroCoupe · Sep 22, 2023

If you are not having to add any I would say you have an air lock somewhere.

85GTStangGuy · Sep 22, 2023

Could the water pump be cavitating? Are you sure you have the correct rotation water pump on it?

Noobz347 · Sep 23, 2023

Where is @General karthief ? I've seen him talk about jacking up a corner before but don't remember what year or under what conditions.

General karthief · Sep 23, 2023

Noobz347 said:
Where is @General karthief ? I've seen him talk about jacking up a corner before but don't remember what year or under what conditions.

My method of 'burping' the system would be to jack that muth'r up (safely of course) open the radiator cap and run the engine up to temp, let it cool, top it off and run it again.
Did I read he used a funnel when he filled it? Don't remember and ain't go'n back.
He's likely going to live with the bubbly/gurgle sound that sometimes happen with heater cores, but he describes a drip sound (?) so I suspect he's hearing the 'tic tic' that happens when two different metals are bolted together like headers bolted to heads. I would, if this is the case, check the header bolts, pipe to header flange bolts.
None of this is backed up with any real mechanical experience, results may very.

beeduckworth · Sep 30, 2023

The other thing I find odd is if the vehicle is cold and I remove the Cap the coolant is fully topped off. I start the motor with that sealed air burp funnel connected it will fill almost 3/4 full of coolant before thermostat opens and then will suck most of it back in.

I can do that 10 times with exact same result...

I've never had a car that would push out that much coolant untill thermostat opens. I can't remember any vehicle of mine pushing any liquid out for that matter.

What do yall think about that?

Noobz347 · Sep 30, 2023

That still sounds to me like you have a sizeable air pocket somewhere.

Lemme ask you this:

Have you ever seen the temp gauge shoot up high and then for no explanation, show normal again a short time after?

KRUISR · Sep 30, 2023

Like others, I think the bubbles are trapped air. This latest thing you mentioned (cap off filling the funnel on a cold start) makes me think that more as well. Here is my theory, you have trapped air in the block. When you cold start with cap off that trapped air heats and expands. Because the t-stat is closed it can only expand back through the water pump back into the rad, hence the coolant level rises in the funnel.

To try and burb the air from the block you could loosen or remove the gauge temp sensor (driver side of intake near first intake runner). That could give the trapped air an out without having to be pushed through the t-stat. The top of the rad is higher than this sensor location so if you remove the sensor, coolant should come out by gravity. Another spot to vent the trapped air before starting could be the hose that goes from the coolant tube on the passenger side to the EGR spacer. Un hook the EGR spacer end and place in a small bottle or container (to not get coolant all over the engine). If you start with the rad cap off and work on the sensor or the rubber hose, when coolant comes out cap the rad and put it all back together.

Then I would cold start the car with the rad cap off and your funnel hooked up (less mess). Then when you start, let the coolant level go down in the rad tank as much as half way (add a little if needed) and let the coolant circulate through the rad (watching it come out of the core tubes) for 5+ minutes. During this time the t-stat could close and coolant level will come up quickly (also if you have electric fans, they will likely come on during this time too). Then I top up the rad and put the cap on before it overflows. I shut the car down and after it has had a time to cool down I check the overflow tank and top up as needed.

limp · Oct 1, 2023

KRUISR said:
Like others, I think the bubbles are trapped air. This latest thing you mentioned (cap off filling the funnel on a cold start) makes me think that more as well. Here is my theory, you have trapped air in the block. When you cold start with cap off that trapped air heats and expands. Because the t-stat is closed it can only expand back through the water pump back into the rad, hence the coolant level rises in the funnel.

To try and burb the air from the block you could loosen or remove the gauge temp sensor (driver side of intake near first intake runner). That could give the trapped air an out without having to be pushed through the t-stat. The top of the rad is higher than this sensor location so if you remove the sensor, coolant should come out by gravity. Another spot to vent the trapped air before starting could be the hose that goes from the coolant tube on the passenger side to the EGR spacer. Un hook the EGR spacer end and place in a small bottle or container (to not get coolant all over the engine). If you start with the rad cap off and work on the sensor or the rubber hose, when coolant comes out cap the rad and put it all back together.

Then I would cold start the car with the rad cap off and your funnel hooked up (less mess). Then when you start, let the coolant level go down in the rad tank as much as half way (add a little if needed) and let the coolant circulate through the rad (watching it come out of the core tubes) for 5+ minutes. During this time the t-stat could close and coolant level will come up quickly (also if you have electric fans, they will likely come on during this time too). Then I top up the rad and put the cap on before it overflows. I shut the car down and after it has had a time to cool down I check the overflow tank and top up as needed.

I watched a radiator shop pull a heater hose line off the firewall to get rid of an air bubble in the cooling system...

nickyb · Oct 1, 2023

That video shows a lot of bubbles that keep comming, so I'm thinking somehow air is getting In to the coolant.
First thing come to mind is headgasket. I know you said you tested it, but what else could it be??????????

KRUISR · Oct 1, 2023

limp said:
I watched a radiator shop pull a heater hose line off the firewall to get rid of an air bubble in the cooling system...

Same thing as the smaller hose going to the EGR valve.

Engine Never ending bubbles at radiator cap opening??

beeduckworth

New Member

AeroCoupe

lube between the nut and the face. I know my lubes

beeduckworth

New Member

AeroCoupe

lube between the nut and the face. I know my lubes

85GTStangGuy

Noobz347

Stangnet Facilities Maint Tech... Er... Janitor

General karthief

wonder how much it would cost to ship you a pair

beeduckworth

New Member

Noobz347

Stangnet Facilities Maint Tech... Er... Janitor

KRUISR

limp

wrap a little cheese around it and its a done

nickyb

I gotta say i never painted my nuts, Never Ever

KRUISR

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Engine Never ending bubbles at radiator cap opening??

New Member

lube between the nut and the face. I know my lubes

New Member

lube between the nut and the face. I know my lubes

Stangnet Facilities Maint Tech... Er... Janitor

wonder how much it would cost to ship you a pair

New Member

Stangnet Facilities Maint Tech... Er... Janitor

wrap a little cheese around it and its a done

I gotta say i never painted my nuts, Never Ever

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