More info on bubble test for HG leakage?

[e9999]

Remembered reading Robbie's discussing his bubble test.
Planning to check this before too long for peace of mind.
Did a search to look for more info on this but didn't find much more than Robbie saying to run the engine at 4K and looking for bubbles.

Anything else to know / do?
You just leave the overflow cap tube in the coolant and peek through the top? Or add an extension hose maybe, seems like that would be easier.
The overflow tank doesn't need to be capped for this I imagine.
Best yet, maybe run the cap tube in a clear bottle with some water on the side?
How long at 4K would it take for bubbles to be seen if there is a HG problem?

 

[Lars]

FYI...... bubbles appeared in mine right at startup with the engine at idle rpm's. And yes, my head gasket was toast.

Just lift the cap enough for to be able to look in the overflow tank but still keeping the hose submerged. Nothing tricky about it.

 

[e9999]

FYI...... bubbles appeared in mine right at startup with the engine at idle rpm's. And yes, my head gasket was toast.

Just lift the cap enough for to be able to look in the overflow tank but still keeping the hose submerged. Nothing tricky about it.

I'm surprised. I would have thought that you had to warm up the engine to the point that the thermostat would open up before any bubble would reach the overflow tank...

 

[Lars]

My coolant could very well have been up to temp. It was dec of 2003 so I dont remember if I did it with the vehicle having sat for a period of time or with the engine already warmed up. I performed the test multiple times over multiple days and each time bubbles were there.

 

[perk]

What type of bubbles indicate HG problems? I've done the test a few times and sometimes I see a few big bubbles at the beginning, but I've been thinking/hoping these aren't the ones No really, aren't these the radiator just burping.

Should the bubbling be consistent? Once, while reving, I thought I saw a couple small ones, but I've done the test a few times and they only appeared that once.

Do you need to rev to 4000? I remember reading 3000 and 3500, but not 4.

 

[landtank]

While reving the engine to @3k you see small bubbles appearing on a regular basis. Not a steady stream but 1 or 2 at regular intervals. And yes the truck needs to be hot so the coolant is flowing through the system. If you have just filled the resevour expect some bubbles as there is air in the system and driving a few cycles to ensure the air has been purged is a good idea since a false reading would mean a big mistake.

 

[e9999]

yup, everytime you open the rad cap there will be air in the rad and I would think it could take quite a while to get rid of this since you are dependent on thermal expansion of both air and water (not much) to push it out.

 

[Trapper]

When I suspected that my HG was toast I tried the bubble test on multiple occasions without ever seeing anything abnormal. Of coarse I then began to see and smell coolant burning in my exhaust. That was pretty convincing.

 

[e9999]

When I suspected that my HG was toast I tried the bubble test on multiple occasions without ever seeing anything abnormal. Of coarse I then began to see and smell coolant burning in my exhaust. That was pretty convincing.

what did it look like and smell like in the exhaust?

 

[2cruisers]

Remember that these cooling systems use a pressure cap on the radiator. When a vehicle warms pressure builds in the system normally. When the pressure exceeds the rating of the radiator cap, coolant will flow into the overflow bottle. When checking for a bad HG we are looking for the compression escaping into the coolant systrm,building pressure and overcoming the pressure cap. When this occurs we see bubbles in the overflow tank. This may occur qiuckly or can take some time depending on the severity of the leak. Hope this helps.

 

[robbie]

I was away in south west utah for a week for the kids spring break. I usually look at peoples trucks after they have driven them to the shop and they are still warm. Or I take them for a drive to (15-20 minutes) to get them warm. I am usually seeing a steady stream of bubbles that will occur any where between 3-4 K rpm( can be any where from one bubble at a time to many bubbles on a cycle). others have pointed out good items to be aware of and not taking false reading. There is also the external leaks that happen that will apear from time to time on different engines. So best to look at after warming up and after a drive, or expecially after working the engine hard (long hills are real good, towing heavy loads ETC). One good thing about the pressure cap is that it will take building pressure over 13 lbs to start bubbling the coolant, so a couple of bubbles may be a burb, a steady stream is a problem. later robbie

 

[Trapper]

what did it look like and smell like in the exhaust?

The smell was similar to the sweet smell of antifreeze. I started to notice large amounts of condensation coming out of the exhaust as well. This wasn't your typical thin wisps of condensation on a cold morning, but more like billowing clouds pouring from the pipe. It was more noticeable on start up.

 

[LandCruiserPhil]

Why not side step the guessing and have your coolant and oil tested. Testing will show the slightest of leakage past or present.

 

[sixsracing]

Most radiator shops and competent repair shops have radiator pressure testers. It is a pump connected to a hose with a radiator cap on the end. This is connected to the radiator in the same manner as your cap. The pump is used to pressurize the system and then hold pressure (usually 25-30lbs.) If the pressure leaks down then you look for external leaks, if no external leaks are found then most likely you have a head gasket problem. Of course you can't be sure until the head comes off. The gasket could be fine but the head or block could be cracked. I would have this test performed before I pulled a head off my cruiser. Robbie's test is valid, a steady stream of bubbles is also an indicator. Unfortunately head gasket/head/block leaks can "seal" themselves up depending on temperature and pressure. White flaky deposits on spark plugs and exhaust smell coming from the anti-freeze are tell tale signs too.

 

[Trapper]

A mechanic did something similar with my truck. Along with the pressure test he attached a column with a liquid of some sort to the top of the radiator and watched for a color change during the test. He said the color would change only if exhaust was making its way back through the cooling system and out the radiator.

 

[e9999]

well, after all these discussions of HG blowing left and right, Iwent and tried to see if I have any bubbles coming out in the overflow reservoir. 2 observations:

- dang, 3000 rpm is loud and scary on this engine...
- don't do what I did, which is to pull the cap/tube and stick it in a outside container. The advantage of that is that you could see the bubbles much better, and also see if coolant is coming out (suprisingly the red coolant mix does not mix well at all with clean water under static conditions) which would mean that the cap is opening. However, by removing the tube from the overflow and moving it around I had now introduced air in the tube so that I could well have bubbles coming out because of that. In fact I got a couple of small bubbles and then nothing over 2 or 3 more minutes. I guess that means it's OK but what I'll do next time is to "bend" the tube while still in the overflow so the cap is out of the way and then I can sort of see the end of the tube in the coolant (not entirely obvious)...
It also seemed to be easier to see in there with a flashlight on on the outside at dusk.

Somebody who did the test recently with a busted HG could clarify how fast the bubbles were coming out in his case (e.g. 1 / min, 1/5 secs etc) for the record? [Saw WSDavies saying that had a bubble a second or so. Anybody else?]

 

[honk]

Well, looking for bubbles is best done with the engine at temp and the coolant flowing. Take the radiator cap off (do it before warming the engine is safest), make sure that the radiator is full, and look into the neck of the radiator while revving the engine up and down. The specific RPM doesn't much matter. As you rev you'll see coolant flowing past the opening and if the head gasket is well blown into or between combustion chambers the bubbling will be readily apparent. This about looking at the coolant overflow tank really only shows air in the cooling system and I think it's pretty much meaningless. And this about counting tiny bubbles in how many seconds is ridiculous.

A cooling system pressure tester by Stant costs about $75. last I knew, and can give a better test of the overall sealing condition of the cooling system. External leaks will usually come out on the ground and you track them down. Internal leaks can be many things and it's then time to do a combustion leak test - the one described above with the changing color detecting combustion gasses in the cooling system. Kits for that test cost more and have consumables that have to be replaced.

Air is compressible and coolant is less so. Any air in a coolant system will give a slow drop in the reading on a coolant system pressure tester (the pump) because the air in there is squeezing and taking up less space in there.

Frankly, from what I've read here I think that most people here would be well served to have their cooling system professionally tested with an eye to a possible head gasket problem. Tell the guy that your engines all have a historical problem in that area so he'll give extra attention to the possibility.

There's no substitute for experience and cooling system/head gasket/cracks et al can be difficult to pinpoint even for a pro. Don't risk losing your engine and suffering VERY extensive (read expensive) repairs by relying on amateur guesses, rumors, and half-baked expertise gained in a chatboard.

 

[e9999]

by opening your cap, you will depressurize your cooling system. On the one hand I guess that could mean that gases could get in more easily from the cylinder, OTOH, you may create boiling at hot spots which may create bubbles of its own? Maybe even entraining air through the cap opening?
Not obvious that is better.

 

[powderpig]

First it is interesting that some one that does not own a 80 series or OMG owns a ford. Is giving half baked advice and getting in the middle of a discussion with out reading much in the way old posts from the past.
Most modern systems have a different flow system then the older 40/60 stuff. Never remove a cap on a 1FZ engine with it running, fluid will go all over the place and you run the risk of burning your self. If you try to start the truck with the cap off and then it warm up and the thermostat opens it will again flow to the point it will go all over. Where the cap is and the flow system, it will make it real hard to see the bubbles. As for having the cap on it allow the pressure to build up and supply a stead stream if it builds past the caps pressure.
I reccommend the bubble test as I beleive it can pick up some sign of a problem that some times be difficult to detect before a major failure. By having a fully warmed up system, ( i usually like to run a vechicle hard up a long hill). If the pressure cap is working properly and allows the system to build to 13 psi then any blowing of bubbles into the over flow tank at a constant rate either a bubble every second or a steady stream can be one of several minor test that can lead you to the concuslion that you have a problem. The bubble are some form of gas (air, co, etc). This gas is introduced from some where. If the water pump seal is good (no leaks at shutdown) then usually there is no sucking air in. If coolant is a mix of water and coolant, usually no micro bubbleing happens from the cylinder wall temps. Yes it would be best to confirm with a CO detector to be ultra sure, but if it is a steady stream it will be combustion gas no doubt in my mind.
Yes CO detectors are used to also, yes some may better off going to a profesional (that may or may not detect a problem). Some times stuff is taken out of context and people on pick on what they want to see. I use this as one of many methods to diagnosis fully what a problem is. For me it is a big sign on these 80 series 1FZ engines. These boards I believe are to help people understand their vechicles and to help with getting the problems they have and to have a idea before they take it to a professional or to help with the repairs them self. You may agree or not.
SO what do you Honk come to the 80 series forum for? Thinking about a 80 series or just to give your views on how to diagionsis old hardware or Fords?
later Robbie

 

[aey_bee_see]

newbie question re bubble test

if i am getting this right, i should:
- have a very warm engine
- rev 3k at park
- rad cap is ON
- observe overflow hose for bubbles
- if steady flow of bubbles then i've an impending hg problem

thanks.