This Has To Be Head Gasket Going Out Right?

[vwdmc16]

My car's cooling system is still clinging on to the edge of sustainability. For the last two years at least it ive noticed the coolant in the header tank will begin to disappear after a week of driving, quicker if the driving is spirited or in 80'+ temps. I have to keep a close eye on it or it will eventually begin to suck air annd no longer cool, I will get a warning that im on the edge as the water temp climbs from above the 160' notch to hover near the 220 mark, at that point I have to turn off the AC or turn on the heat to keep it down but that only makes it last another 10 miles. This has only been a repeatable problem when the outdoor temp is 85'F + and or I do some sustained 80 mph cruising. A few weeks back I drove to Monterrey, ca from Sacramento and back in 50-60'F temps and i lost very little coolant.


In this video My car is fully warmed up after a 8 mile drive around the neighborhood in 82' temp with the A/C cycling all the time. The gauge reads between the 160' notch and 220' Notch which is typical for my car in this ambient temp. With my trusty infrared Temp gauge you can see the water temp coming from the radiator is about 170' and the water leaving the thermostat to the radiator is about 200'. I also read about 200' at the back of the cylinder head where the temp gauge sender is.

Last I show my overflow bottle that installed back when I began to loose coolant and i wanted to track if it was coming out of the overflow tube of the header bottle. This is where all the coolant exits the engine, not at head gaskets externally or at any cooling hose junction. The car leaks oil but never coolant.
You will note that there are alot of bubbles coming out of my over flow bottle which was empty when I set off this morning too.

Header cap is pretty new and is the forth one I have bought over the years, I have tested the cap with a pressure tester, it is a 15lb cap that releases pressure just over 15psi.

Header tank-cap seal surface is clean and smooth, cap feels tight and secure when on the bottle. My coolant system is simply running far more that 15psi when hot and at pressure.

I believe I have a small leak between a combustion chamber and its surrounding water jacket. When hot enough it opens and the higher pressure combustion pressure is pushing into the coolant over loading the system That is the bubbles you see in the bottle. I have zero coolant in the oil and zero oil in the coolant. I have had the oil analyzed for coolant traces from Blackstone Labratories, Sodium and Potasium were higher than normal but not conclusive as ethylene glycol.

Im waiting on a kit to arrive that tests for exhaust traces in coolant for the final conclusion, Meanwhile check out the video and see if you have any more ideas.




http://youtu.be/olcviBA1GvI

[NightFlyer]

That's odd.

The fact that it's not really getting hot, but pushing coolant out of the header bottle suggests an improperly sized (or improperly functioning) water pump IMHO. It's as if the pump is creating too much pressure by turning the impeller too fast. Do you have the correct sized pulleys on the crank and water pump / alternator? If using modified parts, did you account for the changes in selecting the proper sized pulley for the water pump?

Either that or there's some blockage somewhere in the system creating too much back pressure. Did you make sure that none of the hoses and pipes in the system are kinked and/or restricted in any way?

About all that I have for you.

Best luck

[Soundkillr]

I had a head gasket failure on my daily driver. Did exactly what you have. No oil in water, no water in oil. Leak was head gasket and combustion pressure was pushing exhaust into coolant system, and the overflow bottle would bubble like crazy. Looked like it was boiling when i would rev it up. In my case it would push coolant out the overflow bottle and onto the road....

[AugustneverEnds]

Have you ever been in an emergency and topped up with tap water? You MIGHT have a localized blockage somewhere but it seems very unusual that a one-time top up would cause such a huge blockage unless you were using water from the Dead Sea. Just my thoughts...

Good Luck!

[D Knight]

You can test this with a tool designed for this purpose. It had a fluid that will change color with combustion gases. You remove the cap ( be very carefull if the engine is warm) and put the tool over the opening. Some look like a giant syringe, others have a vacuum line on them to draw the gasses into to cylinder. Fill the tool with the specified level of test fluid and wait to see if it changes color. If it does you either have a crack or a head gasket is failing. Your local oreilly has these tools to rent if you don't want to buy one.


-D Knight-

[Ryan S.]

Clint,
I have a UVIEW 5600 combustion leak tester you can borrow, if you haven't ordered your own kit, yet.

[Rich]

I had a head gasket failure on my daily driver. Did exactly what you have. No oil in water, no water in oil. Leak was head gasket and combustion pressure was pushing exhaust into coolant system, and the overflow bottle would bubble like crazy. Looked like it was boiling when i would rev it up. In my case it would push coolant out the overflow bottle and onto the road....

Sounds like a head gasket gas test is in order for sure, Clint.

Meantime you might try warming the car up with the tank cap removed and take a look inside, especially with some revs, to see if there are bubbles appearing in there. You may need an inspection mirror to look right at the main hose connection to the tank. It will be worse at higher revs and higher load.

I hope it's something else....

[vwdmc16]

Ok im back with results, Picked up the combustion leak tester from Ryan and it is moderately conclusive. So the fluid in the tester turns from blue to yellow with the addition of co2, however the tester only turns a light green, which is the result expected for a Diesel. Visually it is still pretty conclusive as the bubbles pushed into my overflow tank get much larger and more vigorous as I rev up the engine.


coolan2.jpgcoolant1.jpgcoolant3.jpg

[David T]

Ok im back with results, Picked up the combustion leak tester from Ryan and it is moderately conclusive. So the fluid in the tester turns from blue to yellow with the addition of co2, however the tester only turns a light green, which is the result expected for a Diesel. Visually it is still pretty conclusive as the bubbles pushed into my overflow tank get much larger and more vigorous as I rev up the engine.


coolan2.jpgcoolant1.jpgcoolant3.jpg

The color change is not always so obvious. If you get a color change you can figure you have combustion gases in the coolant. If the test fluid is old, the coolant is dirty, etc you don't always get the results you expect. If you have bubbles you really didn't have to waste time testing to confirm. You can also pull the spark plugs and look for signs of coolant and do a compression test. All of this is moot, bubbles in the coolant is definitive for a blown head gasket. As much as you have confirmed this you also need to know WHY the head gasket popped. Was it a coolant leak, a bad otterstat switch, a bad thermostat, etc? If you don't find and fix the cause of the overheat you stand a good chance of blowing the head gaskets again. The failed head gasket is a symptom, NOT a cause.

[Ryan S.]

Clint
I couldn't tell for sure from your photos but the bottom chamber looks like it is not filled upto the line.
Mine stayed blue for both chambers.