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Antifreeze Volcano - Air Pocket or Head Gasket

11K views 28 replies 9 participants last post by  a380airbus  
#1 ·
I have a 2013 Jeep Wrangler Sahara Unlimited, 3.6L with about 160,000 miles. I got a check engine light , P128, which either points to the thermostat or the temp sensor in the block. I changed out the sensor first, and when doing so the coolant system was sealed other than the sensor coming out of the block. Little to no anti freeze came out when I swapped from old to new sensor and thought it was strange. Pulled the battery terminals off to clean them and left them off for well over 30 minutes. Reinstalled terminals and went for a start. Temperature gauge in the Jeep was reading normal after running the Jeep to operating temperature, as it was exhibiting with the old sensor. A day or two later P128 came back. Tried to clear the code but it was a hard code and would not clear, but the check engine light went out.

At the same time I changed the oil, and after starting the vehicle to get new oil circulating I got an oil pressure code that is a hard code as well and will not clear. I would assess that the ECM hard codes these issues until a series of driving the vehicle to ensure the problem is remedied??? In any event in the middle of this the P128 code/check engine light came back. I have replaced a radiator in this vehicle as well as a thermostat a couple of years ago prior to the thermostat I just installed and never had an air pocket or issue burping this cooling system. There is currently no oil in the antifreeze, not sign of anti freeze in the oil, no white cloud coming out of the exhaust with the exception of condensation from sitting for the past week.

I have a cooling system that is misbehaving and I cannot burp it. Tried everything but putting the damn thing on a chain hoist and pointing the nose of the Jeep vertical in the air. I have tried burping this thing three times, spent over 100.00 in 50/50 Chrysler mix, get the majority of the air out, put the cap on and the overflow jug starts to dance or of you leave the cap off to continue to fill the system the radiator at some point after the thermostat opens starts to act like the coolant is boiling and starts blowing out of the radiator fill, and all the while the temperature gauge is reading normal in the Jeep.

I performed a compression test yesterday and all cylinders were showing 150psi on the gauge with the exception of the no. 1 cylinder, which came in around 110 at first, then worked its way up to 150 after three or four repeats of the test. I did not shut the fuel injector system down (not sure if I just pull the fuel pump fuse or any other way) so my assessment was that the cylinder took on fuel and the compression improved because of the gas in the cylinder. Will duplicate the test today. Prior to pulling the engine apart to get to the spark plugs the engine ran great with no noises or skips/stumbling. The limits for the compression test that I found on line were 100 PSI with a 25% differential from all other cylinders and could not be under 100 psi. If the #1 cylinder tests good this morning what can I do to burp this thing? Anyone else experience this?
 
#2 · (Edited)
... or of you leave the cap off to continue to fill the system the radiator at some point after the thermostat opens starts to act like the coolant is boiling and starts blowing out of the radiator fill ...
Welcome to the forum!

I experienced the same thing when trying to refill & burp my 2014 after replacing the oil filter housing. As soon as the thermostat opened at a little over 180F, coolant started gushing out of the radiator. I found unclipping the bottom hose and moving it around got out a lot of air. After that, for me, the 'trick' was to: 1) Make sure the coolant overflow bottle is filled to the max level. 2) With the engine cool, top up the radiator with coolant and install the radiator cap. 3) Start the engine. 4) Let the temp get to about 180F - 190F. 5) Shut off the engine and let cool for about 30 minutes. 6) Remove radiator cap and top off coolant. 7) Repeat steps 2 thru 6 until the radiator does not need to be topped off any more.

Getting air out of the cooling system is a common issue. If you search the forum you will find a lot of useful information, and what has worked for other people.
 
#3 ·
A day or two I have tried burping this thing three times, spent over 100.00 in 50/50 Chrysler mix, get the majority of the air out, put the cap on and the overflow jug starts to dance
That is what you want to happen. Once the jeep cools (and provided everything is working properly and you have no air leaks), the coolant which gets expelled into the overflow will get sucked back into the system.

That's how cooling systems work. The coolant expands when heated and needs someplace to go (the overflow tank). When the jeep cools the coolant contracts, causes a vacuum and the expelled coolant gets sucked back in. Indeed... if you have a lot of air in the system, this NATURAL process won't happen.

And don't keep taking your rad cap off. You introduce air and destroy the vacuum flow between the rad and the overflow tank.
 
#7 ·
Thanks Bob. Been twisting a wrench since 1979 and never experienced an issue with air locking up in a system like this. From what it sounds I have been lucky. I have not been in the automotive industry full time in order to understand the new quirks mechanics are running up against.
 
#4 ·
Have you tried releasing the air behind the thermostat with the bleeder valve? There is a plastic screw on top of the thermostat housing and that opens a passageway to behind the thermostat to let any air trapped behind it out. I had some issues bleeding the system through the radiator cap until I found that. Once I knew about it, it went much better. I burped the top hose to get as much air out as I could, then ran the motor up to operating, cracked that until the air stopped and got a stream of antifreeze, then topped off and did it once more. After doing it twice, the rest of the air came out over normal driving and the fluid in the overflow tank filled her up as normal.

These can be helpful for getting the initial fill in.
 
#5 ·
I did. I also filled up the engine block with antifreeze before I put the thermostat in as well. used the bleeder clod while filling the system as well as hot to release any air I could. I will check out your link thanks!
 
#9 ·
I have a 2013 Jeep Wrangler Sahara Unlimited, 3.6L with about 160,000 miles. I got a check engine light , P128, which either points to the thermostat or the temp sensor in the block. I changed out the sensor first, and when doing so the coolant system was sealed other than the sensor coming out of the block. Little to no anti freeze came out when I swapped from old to new sensor and thought it was strange. Pulled the battery terminals off to clean them and left them off for well over 30 minutes. Reinstalled terminals and went for a start. Temperature gauge in the Jeep was reading normal after running the Jeep to operating temperature, as it was exhibiting with the old sensor. A day or two later P128 came back. Tried to clear the code but it was a hard code and would not clear, but the check engine light went out.

At the same time I changed the oil, and after starting the vehicle to get new oil circulating I got an oil pressure code that is a hard code as well and will not clear. I would assess that the ECM hard codes these issues until a series of driving the vehicle to ensure the problem is remedied??? In any event in the middle of this the P128 code/check engine light came back. I have replaced a radiator in this vehicle as well as a thermostat a couple of years ago prior to the thermostat I just installed and never had an air pocket or issue burping this cooling system. There is currently no oil in the antifreeze, not sign of anti freeze in the oil, no white cloud coming out of the exhaust with the exception of condensation from sitting for the past week.

I have a cooling system that is misbehaving and I cannot burp it. Tried everything but putting the damn thing on a chain hoist and pointing the nose of the Jeep vertical in the air. I have tried burping this thing three times, spent over 100.00 in 50/50 Chrysler mix, get the majority of the air out, put the cap on and the overflow jug starts to dance or of you leave the cap off to continue to fill the system the radiator at some point after the thermostat opens starts to act like the coolant is boiling and starts blowing out of the radiator fill, and all the while the temperature gauge is reading normal in the Jeep.

I performed a compression test yesterday and all cylinders were showing 150psi on the gauge with the exception of the no. 1 cylinder, which came in around 110 at first, then worked its way up to 150 after three or four repeats of the test. I did not shut the fuel injector system down (not sure if I just pull the fuel pump fuse or any other way) so my assessment was that the cylinder took on fuel and the compression improved because of the gas in the cylinder. Will duplicate the test today. Prior to pulling the engine apart to get to the spark plugs the engine ran great with no noises or skips/stumbling. The limits for the compression test that I found on line were 100 PSI with a 25% differential from all other cylinders and could not be under 100 psi. If the #1 cylinder tests good this morning what can I do to burp this thing? Anyone else experience this?
So I went out and performed a compression check this afternoon to validate my findings from yesterday. this time #3 cylinder was not reading well at 60 psi. I performed the test multiple times on #3 cylinder and it finally came up to 120psi. I drained all of the antifreeze out of the vehicle and started with filling the block first, then the radiator while bleeding the thermostat housing. I also bought the funnel system to burp the system with and connected it to the radiator. Started engine and burpped engine as best as I could. then out of nowhere the antifreeze got violent and sprayed everywhere.
 
#10 ·
So I went out and performed a compression check this afternoon to validate my findings from yesterday. this time #3 cylinder was not reading well at 60 psi. I performed the test multiple times on #3 cylinder and it finally came up to 120psi. I drained all of the antifreeze out of the vehicle and started with filling the block first, then the radiator while bleeding the thermostat housing. I also bought the funnel system suggested to burp the system with and connected it to the radiator. Started engine and burped engine as best as I could by squeezing the hoses, cycling the accelerator and trying to bleed off the thermostat housing. I thought I was making progress, then out of nowhere the antifreeze started to boil out of the funnel and spray everywhere. I will submit a video of the experience ass well as a pic of the temperature gauge.
 
#12 ·
In any event I tried uploading the two video clips and it will not upload. The funnel on the top of the radiator with the engine hot backfills the funnel, it overflows and boils violently everywhere. You shut it down and it continues to boil, then in an instant sucks fluid back in after many minutes, all the while the temp gauge reads normal in the Jeep.
 
#14 ·
In any event I tried uploading the two video clips and it will not upload. The funnel on the top of the radiator with the engine hot backfills the funnel, it overflows and boils violently everywhere. You shut it down and it continues to boil, then in an instant sucks fluid back in after many minutes, all the while the temp gauge reads normal in the Jeep.
Host them on Youtube and post the links to them here.
 
#20 ·
I tried every trick in the book, still boils either in the reservoir or the radiator with the special funnel on it, or not. My last go at it was fill the radiator, burp it, put the cap on, fill the reservoir, start it and run to 190F. Shut down, wait 30 minutes, then repeat the process till there is no air. Did this for a few hours, the reservoir stayed full, ran it for a while, and then the reservoir started to dance/boil and this was with the radiator cap on / closed system. I have a post I posted this morning regarding the current status of where I am at a few minutes ago.
 
#18 ·
Well after numerous attempts of different styles to deliver anti freeze into the system as well as compression readings that were weird, as well as utilizing another compression tester to verify the data I was reading, it appears #3 cylinder is flagging a misfire code P303 off and on, pulling weird compression readings on the same cylinder, was also flagging P2173, which I changed out the MAP sensor and did not work, P0520 which has no relevance to the rough running condition and still have the original code of P128 that will not clear. I did change the thermostat earlier, thanks for the advice Michael, but will pull another compression check on #3 cylinder and see if it is still questionable or not. I say this because you start performing your checks and it might read 80, 60, 150, 100, and of course, as you continue the compression starts to get better because of fuel, oil and heat as well as anything else sealing up the cylinder for it to read within limits. This one has been a head scratcher because until now there have been no traditional telltale signs of WHAT it might be. I was going to remove the right head this weekend and see if I was lucky enough to see a blown head gasket, but at 160,000 miles I am itchy and scratchy of pulling the head bolts out with the internal threads of the block because of dissimilar metal corrosion. I still may pull the head just to satisfy my curiosity. Be great to just stuff a 350 crate motor in the thing......
 
#21 ·
Can you get a fiber camera to look in the cyl? Before pulling the head.

Also, stop with the Mopar coolant. It's not good. The $7 prestone coolant at Walmart works the same without all the headaches we all have been battling with the Mopar stuff.

Why do we pay so much for it? We're suckers!

I only put back in the amount that the manual says it needs. The guessing game is never good. I'll check the level after some driving.
 
#22 ·
Can you get a fiber camera to look in the cyl? Before pulling the head.

Also, stop with the Mopar coolant. It's not good. The $7 prestone coolant at Walmart works the same without all the headaches we all have been battling with the Mopar stuff.

Why do we pay so much for it? We're suckers!

I only put back in the amount that the manual says it needs. The guessing game is never good. I'll check the level after some driving.
You know that is a great idea!!! I have a Milwaukee fiber optic camera and screen. Hopefully I can get the bend at the end of the optical part so I can look at the head and around.
 
#23 ·
Not exactly sure what problem you are trying to solve anymore. But your coolant will boil in the overflow. Your coolant will boil with the funnel attached. There is nothing wrong. Coolant boils especially when not under pressure of the radiator cap. But your cooling system is not under pressure in the overflow and will boil at 212* (Like water). To burp the system, do multiple heat up to ~200 and shut off with the Jeep at an incline with the funnel attached with coolant in the funnel. Let Jeep fully cool with the funnel on. Then call it good.
 
#24 · (Edited)
But your cooling system is not under pressure in the overflow and will boil at 212* (Like water).
No.
PURE water boils at 212 at atmospheric pressure.
Coolant (at 50/50 mix) boils at around 223~226 atmospheric.

The thermostat opens at 203. If you are careful not to overdo it (jamming the gas pedal), then you can get the thermostat open without hitting the boiling point

People attempt to speed up the heating process by goosing the gas, but what ends up happening is that you overshoot the 203, hit the boiling point and get a volcano. You have to remember that the temp sensor is on the engine OUTPUT of the cooling system so water ever your reading on the dial.... it's probably another 10 degrees hotter directly in the head.