Coolant leak but passed combustion in coolant and pressure tests
 

I have had a leak in the coolant system for a little while but have been able to top it off every time I see the level dip. I just did some tests and found no combustion gas in the coolant, and no leaks found from the pressure test. There has been some white smoke coming out of the tailpipe with a bit of water dripping but it is not severe. It also doesn't smell like coolant - just like regular exhaust but more humid. Any ideas what could cause it?

If you need any other information please let me know! Thanks.

Well you have already done the 2 big test most of us would suggest to do. If you are still having trouble finding the leak then it might be time for a UV dye test to help locate it.

How much coolant are you loosing exactly?

The coolant has to be going somewhere and if you didn't find any leak externally with the pressure test then I'm leaning toward either a very small or hard to see external leak or it's an internal leak. Small external leaks can be hard to spot so you might want to do it again with UV dye.

How does the oil look?

Have you checked the throttle body heater under the throttle body?

I can't really quantify the coolant loss. It is not substantial. I drive every day to work about 2 miles in low MPH. I lose only a small amount in this time and top it off with just a bit of coolant. I can measure it but it will take a couple of weeks to lose it first...

The oil is a little dirty but looks like oil - no milkiness or frothiness I have read about.

I have checked the throttle body and while there are no puddles, there is some dried red stuff around one of the hoses. Could this be a leak?

I was planning on replacing the hoses soon so I may replace the heater as well.

The dried red stuff is more than likely coolant. A picture would help. Do you still have the orange Dexcol coolant in?

Does the red stuff look like this?

Attachment 37729

It's less pink and more rust/orange colored...

It's leaking from either a split hose or the throttle body heater. I would just replace the heater and install new hose clamps if the stock ones are still on there.
Throttle Body Heater Plate Kit (Genuine Part # MGM000010) | Land Rover And Range Rover Fuel System Parts
http://www.roverparts.com/product/im...GM000010KG.jpg

One thing to remember is some of these trucks like to run with the coolant at less than max level.

If I fill my reservoir up all the way, within a few days it will have dumped itself down to about an inch and a half below the filled line. If I leave it alone, it will hold that level indefinitely.

So I just quit topping it off, and I check it a couple of times a week. It has been stable for at least a year now.

new TBH need

Is the pressure test done while running or static? Also, how does the exhaust test work?