1KZ-TE Coolant in cylinder head help.

[JDuc1]

Really need some help figuring out what is happening with my Hilux Surf. I randomly found I was loosing coolant. No visible leaks lead me to think is was a Cylinder head issue. I took it to the shop and they did a two Carbon Dioxide tests on the radiator and found no exhaust gases present. Good right? Well I thought that until I took off the manifold while doing a EGR delete and found coolant sitting in the first inlet chamber. See pictures for all four chambers. I just need some help answering basic questions... Annoyed and not looking forward to a possible head replacement!

How could it pass the carbon dioxide test?

Why is the coolant pooled only in that first chamber?

Could the leak into the head be coming from anywhere else besides either a head gasket or cracked head?

 

[FJBen]

Really need some help figuring out what is happening with my Hilux Surf. I randomly found I was loosing coolant. No visible leaks lead me to think is was a Cylinder head issue. I took it to the shop and they did a two Carbon Dioxide tests on the radiator and found no exhaust gases present. Good right? Well I thought that until I took off the manifold while doing a EGR delete and found coolant sitting in the first inlet chamber. See pictures for all four chambers. I just need some help answering basic questions... Annoyed and not looking forward to a possible head replacement!

How could it pass the carbon dioxide test?

Why is the coolant pooled only in that first chamber?

Could the leak into the head be coming from anywhere else besides either a head gasket or cracked head?

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Not an expert on the 1kz or 2lt etc, but I’d say you’ve Probabaly guessed right. Headgasket and/or cracked head.

My guess is both as it’s fairly common, but the answer is to pull it apart and see.

 

[Eurasiaoverland]

On an older (pre-2000 according to @Dougal, who is far more knowledgeable than I am) 1KZ it's almost a matter of waiting until the cylinder head cracks. No CO2 in the coolant system means no cylinder to coolant passage crack, but yours is most likely cracked up behind the valves. Time to take the head off to check.

The only other possible explanation would be that coolant is leaking from the turbo, though I have never heard of this happening. Given the reputation of the 1KZ you can pretty much guarantee it's being sucked into the engine through a crack in an intake port.

 

[Dougal]

Diesels don't produce as much CO2 as petrols so the tests aren't as conclusive.

Doesn't matter though, time to buy a new head and gasket. You're not going to re-use either.

 

[TheBussman]

c02 test is a good one but there are many head and or gasket failures I've seen that it won't pick up. oil analysis is a better test.