Another update found my situation oddly on a diesel tractor forum

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Bad news for me is it matches my symptoms, and it is January in Vancouver snow, rain, rain and snow just crappy weather to be working in the driveway. But it will take a few weeks to get the parts, so there should be a couple of feet of snow by then with my luck.

I am still going to go through the combustion gas check, just because it is good practice to check everything. But of course the time of year I may need it to get around, I will be down.

 

Keeping a close eye on this @Richard Gallant . My 2002 D2 is doing literally the identical, same thing. Like, lockstep, same symptoms and behaviors, even temps at the same RPMs, exactly.

 

@Brandon318 I renting am the combustion tester in the am, rain is supposed ease off.

I will post the results for you, my bet is I will have to take her for a drive and run for more than 30 minutes to get things to the fail point and get enough gas to fail the test.

I think it is just beginning to fail, and because I check my truck weekly I caught the coolant loss. Being OCD on maintenance (my wifes words) I kept checking for leaks until found it. I will post images of the gaskets in this thread once I have it apart and try to indicate the failure point if possible. It will be a couple of weeks before I get her torn down, need to clean the garage so I have somewhere to put all the bits.

 

Update did the test today at 2 deg C with a bit of hail

1st thing pictures


Before

After about 4 minutes at idle

Not great but cellphone images slighty green after the test. This indicates a very small leak somewhere.

As well there is moisture in the exhaust but at 2 deg and wet pavement who knows how much, but once again for reference for those of you the south


normal cold weather exhaust - NOT the white exhaust of doom

But notice the amount of moisture on the ground, on a smaller engine with a smaller diameter exhaust this would be bad as that is a fair bit of water. but I honestly do not know if that is normal in the Pacific Northwest the Disco has not moved or been run very long since I started this post so it may be partly residual moisture in the exhaust.


Now it is dumb question time !

Normally at idle with the cap on my coolant level is slightly above the line, during the test it got a lot higher see image below. Is this normal when this system is unpressurized ?


level with cap off and hi tech catch bottle for testing. Normal level is just above the seam line

 

I now have to do a hi rpm test, and if that passes a drive test if necessary to get the system to pressurize, it took about 40 minutes last time so that will be tomorrow's test.

I have considered a Bars stop leak product to get me to March and warmer weather in the event we need the Disco in the next couple of months, it is snow season here and the wife's mother is in a Alzheimer & Dementia facility an hour away.

I know it can be a good stop gap used properly on a good clean cooling system but still all and all I really do not have enough info to go that route and would rather avoid it.

As well to be safe you have to flush the cooling system and use clean water with the sealer and bypass the heater, as that is most likely to get clogged,the flush refill with AF once it has done it's job, better than doing a head gasket in the snow but can still be dodgy.
Currently that is the last resort - if we get weeks of snow maybe thing, and if her mom is doing poorly.

I am wondering if this could be a stupid as loose head bolt.

@Brandon318 I will keep this updated.

 

Re the tank level question above it has returned to normal as the system cooled off.

 

If you think there may be a loose head bolt, that's easy to check. Just remove the upper intake(6 bolts), so you can remove the passenger side valve cover, nothing blocks the driver side.
You can clean and reuse the valve cover gaskets with a little rtv on both sides.
Even though the head bolts are TTY, I would check them with a torque wrench at the ARP stud torque of 70' lbs.
You can do the whole job pretty quickly too.
The cleaning on the valve covers and gaskets would take longer than the 4 bolts per side, and could be done inside to get you out of the cold.
I'm not saying you need to do this either, but if you're considering it anyway, you never know, you might luck out and buy some time.

 

@Sixpack577 yea the thing that throws everyone is the lack of overheat,everything that causes over pressure should cause overheat, even at idle.

I talked to a couple of mechanics I know and the one fellow suggested maybe a loose head bolt. Seeing I have go that far to tear it down it might be worth it, worse case is I find nothing loose, and just keep going.

 

Final answer from a Nissan mechanic I used for many years - head gasket. He said that is typical of a head gasket just starting to fail, it will not overheat, but just over pressure under load.

The reason it is not commonly seen as most people do not pay that much attention under the hood and with modern temp gauges being idiot lights, by the time they know there is a problem the gasket is way gone.

In more interesting news the local Lordco Machine shop here installs flanged liners, and can order Darton, if I had to go that way.

@brandon318 if you have the same symptoms you may be going down the same path, I will post an image of the failure if possible for you.