CONFIRMED HEAD GASKET LEAK--Tiny bubbles... In my coolant

flash7210 · **Posted:** Sat Feb 07, 2015 2:17 pm

For the last few months I've been trying to stop the small but steady coolant losses on my engine. I've replaced several leaky hoses and clamps. The drips and wet spots have stopped but the coolant loss continues and I've been trying to convince myself that it's not a head gasket problem.
All the usual head gasket leak tests have shown negative.
No pressure when cold.
No pressure after idling for a few min.
No coolant in the over flow tank.

Today I did more pressure tests and leak checks.
After those were negative I started up the engine with the rad cap off. Kept the engine at a high idle to help get it warmed up and observed this...

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gmctd · **Posted:** Sat Feb 07, 2015 5:29 pm

flash7210 wrote:

For the last few months I've been trying to stop the small but steady coolant losses on my engine. I've replaced several leaky hoses and clamps. The drips and wet spots have stopped but the coolant loss continues and I've been trying to convince myself that it's not a head gasket problem.
All the usual head gasket leak tests have shown negative.
No pressure when cold. Rad cap bleeds off pressure as engine\coolant cools
No pressure after idling for a few min.Should be immediate pressure here as water pumps against block\head passages and closed t-stat - low coolant levels would result in no pressure and foaming
No coolant in the over flow tank.That's the coolant reservoir, should be half full and under pressure when engine is running

Today I did more pressure tests and leak checks.
After those were negative I started up the engine with the rad cap off. Kept the engine at a high idle to help get it warmed up and observed this...with cold engine\coolant, remove rad cap, start engine, observe coolant in reservoir - combustion\pressure leakage into water jacket produces small bubbles, easily observable with normal coolant level in reservoir
That foam looks like the water pump is cavitating from low coolant level in block

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flash7210 · **Posted:** Sat Feb 07, 2015 6:18 pm

Just to eliminate any confusion...

The coolant tank has over flow partition that is on the drivers side of the tank. The black hose directly below the rad cap leads to that part of the tank.
Coolant tank was filled to the top specifically so that I could identify large bubbles indicating a head gasket problem.
What I got instead was a whole lotta tiny foamy bubbles.
I have never seen coolant foam up like that so I really don't know what it means.

flman · **Posted:** Sat Feb 07, 2015 8:05 pm

I have heard a leaky return line from the rad can cause bubbles as well.

gmctd · **Posted:** Sat Feb 07, 2015 8:57 pm

flash7210 wrote:

Just to eliminate any confusion...

The coolant tank has over flow partition that is on the drivers side of the tank. The black hose directly below the rad cap leads to that part of the tank. Correct, and my bad: the other end of that hose connects to the bottom of the OF tank such that over-flowed coolant will be all drawn back into the system as the engine and coolant contracts while cooling
Coolant tank was filled to the top specifically so that I could identify large bubbles indicating a head gasket problem.
What I got instead was a whole lotta tiny foamy bubbles.
I have never seen coolant foam up like that so I really don't know what it means.
Try loosening the t-stat hose such that any residual air can bleed out of the t-stat housing while observing if the overage in the reservoir drops considerably

When the system is full, any head leakage should result in bubbles rising to the reservoir at idle - the foam is likely resulted by the KJ hose routing and increased idle speed

papaindigo · **Posted:** Sun Feb 08, 2015 10:08 am

My random and maybe/maybe not useful :2cents:

1. I'm not sure I agree with gmctd's comment "No pressure after idling for a few min. Should be immediate pressure here as water pumps against block\head passages and closed t-stat". The issue is how long an idle and what immediate means. A brief idle, say 15-30 seconds, shouldn't result in significant pressure as the water pump is not really pumping against anything assuming the thermostat bypass is working correctly; if it is then coolant is circulating thru the block but not the radiator. NOTE use of the inline tstat mode might somewhat invalidate this comment. If there is significant pressure chat suggests that the pressure is due to combustion leak into the coolant. On the other hand if the idle exceeds a minute or 2 I'd expect increased pressure due to the coolant starting to warm up and expand.
2. the firewall coolant tank and its cap are essentially the top of your radiator. As coolant pressure rises for whatever reason that cap (e.g. the radiator cap) should open at a preset psi and vent expanded coolant into the secondary tank and as the engine coolant cools that expanded coolant should be drawn back into the primary tank until pressure falls below the cap's psi threshold. The secondary tank should have an overflow outlet so that if too much coolant gets into that tank it vents to ground. As I understand it the secondary tank should be dry or near dry on a cold engine but if there is lots of fluid or venting to ground it's likely there is a combustion leak.
3. have you swapped in a new coolant tank cap with the proper psi setting?
4. have you cleaned; rinsed off the engine (no high pressure spray); added UV dye to the coolant; driven; looked for leaks with UV dye (be sure to check hard to see spots like oil cooler on turbo side and EGR side opposite turbo)? Sniffed for sweet coolant smell from heater core and check for coolant drips from heater core drain (should be on firewall below coolant tank).

Wish I could offer a substantive comment on the foam but don't recall ever seeing that. Under pressure there should be no foam and any air in the system should bleed out quickly.

Are you using HOAT coolant?

WWDiesel · **Posted:** Sun Feb 08, 2015 11:35 am

To add to what others suggested:
I have seen this before in gas motors!
Problem was the antifreeze; something in it had either broke down chemically speaking or it had a foreign substance induced into it, or both. I never had the old antifreeze analyzed, just replaced it.
Cure, we drained and flushed the cooling system and refilled with new antifreeze and foaming was gone!

Two questions come to mind?
Do you have the correct antifreeze (HOAT)?
Have you or someone else ever put some other chemical additive into the antifreeze? i.e. stop leak, water wetter, purple ice, radiator cleaner, etc... :roll:

In your case it may be worth a try to drain, flush and install new antifreeze and see if the foaming goes away? :idea:

FYI: Most water pumps only pump in the neighborhood of 5-7 psig; they are a very low pressure systems designed mostly to flow the liquid through the system, not pressurize it. Due to low speed and low pressure, cavitation would be almost impossible within a full system unless something else is going on?

flash7210 · **Posted:** Sun Feb 08, 2015 11:39 am

Performed the same test this morning.
No foam this time. There were some very tiny bubbles with the occasional small to medium size bubble.
Did this while cold and hot (fully warmed up after test drive). No noticeable change in bubbles observed and no significant change in coolant level.

The rad cap has been changed, its a 16 psi cap.
Have not added any dye.
No drips or coolant smell coming from heater core.
No coolant smell anywhere.
I am using HOAT.

I'm wondering if coolant might be leaking into the EGR cooler?
The wires to the EGR valve/solenoid are cut.
I have installed the Weeks Elbow kit, but I did not remove the EGR valve or cooler.
I have checked all the hoses in and around the EGR valve and cooler, none seem to be leaking.
So, I suppose its possible for the EGR valve to be stuck partially open, allowing coolant to leak into the exhaust.
(I have only observed white smoke from the exhaust when the engine is cold, below 40 deg F, and I have been blaming that on my crappy Etecno glow plugs)

The other possibility for a mystery coolant leak, besides head gasket, is a crack at one of the hose connections on the factory thermostat housing. I had to really crank down on those hose clamps to get those connections to stop leaking. Its possible that I over tightened and cracked something. However, I am not currently seeing any leaks from around the thermostat housing.

papaindigo · **Posted:** Sun Feb 08, 2015 11:58 am

With respect to dye. I will only offer that I have personal experience with chasing leaks and depending on the leak location and amount they can be impossible to find by a visual search as the leaking fluid evaporates too quickly to be seen. I'll admit the leaks I was dealing with were not "substantial" say a cup or so every tank full or so but....

WWDiesel · **Posted:** Sun Feb 08, 2015 1:59 pm

flash7210 wrote:

I'm wondering if coolant might be leaking into the EGR cooler?
The wires to the EGR valve/solenoid are cut.
I have installed the Weeks Elbow kit, but I did not remove the EGR valve or cooler.
I have checked all the hoses in and around the EGR valve and cooler, none seem to be leaking.
So, I suppose its possible for the EGR valve to be stuck partially open, allowing coolant to leak into the exhaust.
(I have only observed white smoke from the exhaust when the engine is cold, below 40 deg F, and I have been blaming that on my crappy Etecno glow plugs)

The other possibility for a mystery coolant leak, besides head gasket, is a crack at one of the hose connections on the factory thermostat housing. I had to really crank down on those hose clamps to get those connections to stop leaking. Its possible that I over tightened and cracked something. However, I am not currently seeing any leaks from around the thermostat housing.

Simple solution, completely remove the EGR valve and cooler and cap the two coolant hoses. It is fairly simple to do this, did it on mine when I installed the Weeks elbow kit. :mrgreen:

As to the thermostat housing being cracked; it if was, you would be seeing a leak of coolant in that area... :wink:

gmctd · **Posted:** Sun Feb 08, 2015 3:08 pm

Correct, and my bad, poor choice of words: pressure at 'immediately' would indicate large combustion leak into coolant jacket
The waterpump is capable of ~100gpm in an open system, so the impedance to flow caused by the block, head and t-stat will result in system pressurization shortly after 'immediately'

You can see the coolant reservoir tank volume between "COLD" at the seam and "HOT" at the hash mark is less than a quart, indicating that liquid heat expansion is minimal in a 12qt 3gal system, this including thermal expansion of the block and head
- the open air space above the coolant level is to allow that liquid expansion without blowing the radiator cap - air compresses easier than liquids
- the rad cap is a two-way valve: one spring-loaded to maintain 16psi system pressure, the other opens as system and coolant cools and contracts

In reference to the above post and deteriorated coolant, the HOAT should be replaced with complete system flush at 60months or 65kmi, so the foaming could be related to deterioration

When filling\refilling the system, do you open the air bleed on the radiator until coolant spills out there, closing it to continue refilling?

Also, if you have not, read thru this:

viewtopic.php?f=5&t=80972

flash7210 · **Posted:** Thu Feb 19, 2015 4:59 pm

CONFIRMED HEAD GASKET LEAK

Did a pressure test and not a single drip anywhere.
Pulled all four glow plugs and #2 cylinder was full of water.

tjkj2002 · **Posted:** Thu Feb 19, 2015 11:08 pm

You should not have any pressure in the system,that has been properly bleeded, till the t-stat starts to open(or close to opening).If you do you have a stuck open t-stat.That tank with the cap should be hooked to the radiator and will have no flow or pressure till the t-stat opens.

CONFIRMED HEAD GASKET LEAK--Tiny bubbles... In my coolant

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