Missing coolant mystery

Hi all,
Just thought I would see if anyone can make some suggestions to help me get to the bottom of a mystery I have.
For quite a while now, my 2006 diesel 3ltr D22 has been losing coolant from the expansion tank. There is no evidence of leaks, no puddles, white marks etc.
I have had it to the radiator place and they pressure tested, flushed the radiator, put on a new radiator cap. No difference. They did more testing, checked the heater hoses, core etc. No difference still loses coolant. There was slight evidence of a raditor leak. Put a new radiator in. No difference. Still losing coolant. Best the radiator guys can do now is scratch their heads and hide when I go in there

I took it to my mechanic. He pressure tested it. Couldnt find any leaks. He left it on the pressure tester over night. Started it the morning and it ran for about 20 seconds and conked out. When he started it, it blew a big white cloud. He said its definitely steam (though it didnt smell of coolant) and that it was probably a cracked head or head gasket. He said he didnt have the special tool set the timing belt, and I have to take it to the dealer.

Took it to the dealer. The dealer ran tests. He said there was no evidence of exhaust in the coolant. All the compression ratios were spot on. No evidence of leaks. He says I am overfilling the expansion tank. This makes no sense to me. - primarily because I am not, but they want me to drive it for a while and see how it goes. I asked them about the big white cloud, and they said it would have been the DPF filter cleaning itself out. I said I would have though that would blow black smoke, not white, and they said it can blow white. Not convinced.

There is none of the standard evidence of a cracked head or gasket. The oil is fine. It doesnt blow bubbles into the radiator. Doesnt overheat. Runs perfectly. Doesnt blow smoke (except at the hands of the mechanic! )
I only drive it about 5kms each way to work each day. Hardly even warms up. It loses maybe a centimetre of coolant over about 2 days. The radiator itself is always full, its always down in the expansion tank.

Sorry for the long post, but its been a real saga - one that sadly still doesnt seem to be over.

Any hints as to what it might be? What have all these people missed?

Thanks
ernal

faulty thermostat ?

That was the very first thing I suggested to the radiator guys, but they said it wont be that. They didnt do anything with the thermostat

D22 with a DPF??

ourd40 said:

D22 with a DPF??

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second that. from wat ive heard on here is that dont dont have one only the d40s do

Dont know. I figured the dealer mechanics would know what they were talking about. As I said though, not convinced.
How do I know if it does have a DPF? Where would I find it?

No DPF on a D22 mate.
Only the auto D40s got them.

It doesn't have one. Is the oil milky?

These dealer guys are a worry then!
Oil is not milky. Looks fine on the dipstick

Anything under the oil filler cap? usually the first place moisture shows up

Nope. Nothing under the filer cap. Nice and clean.

Nope. Nothing under the filer cap. Nice and clean.

Bit out there but what about a faulty hose that's dripping water straight onto the engine somewhere. Would explain why there is no evidence of leaking. And it may only open up when the engine warms up? Like i said bit out there but you have already ruled out the obvious.

Thanks. The radiator guys thought that might have been the case too, but they looked all over with mirrors so they could see everywhere. Checked it hot and cold.
The thing I dont get is that it is losing what I would think would be a fair amount. It should be obvious if its going into the motor with that amount. By the same token, I thought it should be obvious if its leaking that much on the outside too. Its got me (and many others) baffled.

Gday ernal, mate i use to own A 06 D22 and i sucked up some water once before i fitted the snorkel this seemed to cause no damage AT FIRST.......
Then after a few weeks i noted the same problem as you, I too checked all the same things as you and my mechanic and two others looked at it and also did PRESSURE TESTS with the same results as you all clear.

What i found later was that it gradually got worse and eventually would randomly hydraulic, i would wait a few minutes and it would start with a cloud of white smoke.

I am NOT saying you have sucked water into the engine, but i do think for what ever reason you do have some sort of crack in the cooling system that is letting a little water into the cylinder and passing straight out the exhaust. This will then not show up with any of the usual symptoms, eg milky oil, bubbles in the radiator.

The only way it will show up on a pressure test is while the motor is hot and under load, obviously this is a little hard to test at that exact point in time.

Anyway at the time of this happening for me i was pretty strapped for cash, so a friend of mine that has been working as a plant mechanic for over 35yrs suggested i try a bottle of "SEAL UP"
Which i did, and what do you know that $10 bottle of stuff fixed all the symptoms and it stayed that way for the next 170'000km until it was written off.

So for the sake of $10 i would give "SEAL UP" a go, it didnt effect my radiator or heating system or anything else for that matter, unlike the old products like "CHEMI WELD"

The only thing you have to do is BEFORE you put it in is really make sure you really flush 100% of the coolant out of the system, to do it properly i undid the hoses on the heater and run the hose through them as well other wise coolants seems to stay in there no matter how much you flush the radiator and engine.

Hope it all works out for you,
Regards,
Nathan.

Did you end up sorting this out?

Thanks for asking.
I havent sorted it out yet. I went back to my mechanic and told him about my experience with the dealer, and he wasnt greatly impressed. I asked him about the EGR, and he wants me to bring the ute around Tuesday so he can swap some hoses around to by pass it and see if that makes a difference.
If that doesnt work, I am out of ideas, and so is the mechanic I think!

Oil pressure is higher than cooling system pressure so a small leak would not show in the oil, it would leak the other way, oil in coolant.

Check the radiator cap, if the seals are gone and the coolant is overflowing, but not being sucked back in, eventually the tank will get full and start spilling coolant.

Coolant always leaves white stains when it drys on a engine.

I can vouch for "Seal Up". I had a crack in the block of my Zook and a bottle of this 3yrs ago worked a treat. Still going w/o any issues.

nathand22 said:

Gday ernal, mate i use to own A 06 D22 and i sucked up some water once before i fitted the snorkel this seemed to cause no damage AT FIRST.......
Then after a few weeks i noted the same problem as you, I too checked all the same things as you and my mechanic and two others looked at it and also did PRESSURE TESTS with the same results as you all clear.

What i found later was that it gradually got worse and eventually would randomly hydraulic, i would wait a few minutes and it would start with a cloud of white smoke.

I am NOT saying you have sucked water into the engine, but i do think for what ever reason you do have some sort of crack in the cooling system that is letting a little water into the cylinder and passing straight out the exhaust. This will then not show up with any of the usual symptoms, eg milky oil, bubbles in the radiator.

The only way it will show up on a pressure test is while the motor is hot and under load, obviously this is a little hard to test at that exact point in time.

Anyway at the time of this happening for me i was pretty strapped for cash, so a friend of mine that has been working as a plant mechanic for over 35yrs suggested i try a bottle of "SEAL UP"
Which i did, and what do you know that $10 bottle of stuff fixed all the symptoms and it stayed that way for the next 170'000km until it was written off.

So for the sake of $10 i would give "SEAL UP" a go, it didnt effect my radiator or heating system or anything else for that matter, unlike the old products like "CHEMI WELD"

The only thing you have to do is BEFORE you put it in is really make sure you really flush 100% of the coolant out of the system, to do it properly i undid the hoses on the heater and run the hose through them as well other wise coolants seems to stay in there no matter how much you flush the radiator and engine.

Hope it all works out for you,
Regards,
Nathan.

Click to expand...

Ok guys, I am back with a bit of an update. I went back to my mechanic and asked him about the possibility of it being the EGR valve. He agreed to "test" is by bypassing the coolant system. He fabricated a hose that effectively bypasses the EGR and I have been running with that for a couple of weeks. It seems to have fixed the problem. The coolant level is still the same now as when I picked it up from him.
Now it seems clear that the EGR needs replacing. The question is, what is that likely to cost?
He suggested when I picked it up that if the bypass fxes the problem, that I could leave it that way. I am not overly comfortable with that. The EGR was cooled for a reason. I cant see it being a problem for town running like I have been doing, but I dont want to be in the middle of nowhere and give me a problem because it over heated.