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I own a 1989 LR 90 TD originally with a 19J engine which I replaced with a 200 TDI 10 months ago. I was lucky enough to find this 200tdi in superb condition (I estimate no more than 35,000 Km) which came off a Discovery. I can't begin to describe how perfect it runs and my satisfaction except that I have a mystery coolant loss of significant qty ~ 4 liter(1gallon) every 10 days!
Repeatedly Inspected everything; no sign of wetness or green coolant coloring.
Checked the plugs, ok.
Pressure tested system; no sign or pressure loss.
Observed exhaust gasses in various conditions (first morning,heavy load etc); no white smoke.
No sign of milky residue on oil filler cap.
No sign of coolant in the oil.
No bubbles in coolant expansion tank and no pressure at all. Even after long drive.
Operation temp very low. 85-87 deg Celsius even after a long drive.
Thermostat 85 deg C. Takes about 30 min to open on standstill running.
Inspected rad for clogging; not clogged. Counter-Verified temps with laser thermometer.
Not even the slightest disruption, noise, studdering, anything other than perfect during engine operation under any condition.

Please help! I am going crazy with this.

Someone suggested that there may be a crack on the head behind the hot plug allowing coolant in the exhaust cycle without affecting the compression cycle. Anyone heard anything of the sort for a200 tdi? Any comments?
 

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This happened in my 2.8. Mystery loss and I ignored it. Coolant in oil is an early death for a turbo measured in weeks or months if your lucky. Dont wait on this. Your oil is probably turning corrosive from the coolant minerals. Get a new head on asap and flush your oil.
 

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Welcome to the forum Yannis

The Tdi engine is a direct injection engine so no hot plug, unless your frend is meaning the glow plug.

The glow plug passage is on the side of the water way deep inside of the head, but I don't think or have seen one Crack there.

When your banks let you have some cash, pull the head off and check it out. Time for a belt change while your in there.

Gallon of water every tens days? Is that driving days or sitting?

Opa
 

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Thanks Mark, can you please explain a bit more?
I can't follow the tech sequence of what you suggest is going on.
 

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Thanks John,
That's driving days.
Ok, no hot plugs. So that's not a possibility. Any suggestion to try?
And hey, no need for salt on the wound... Think I can exchange LR parts for olive oil? Ha ha...
 

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Thanks John,
That's driving days.
Ok, no hot plugs. So that's not a possibility. Any suggestion to try?
And hey, no need for salt on the wound... Think I can exchange LR parts for olive oil? Ha ha...
Check the connections on the heater matrix, there is some potential you could have a leak behind it.

Also fwiw sometimes an air bubble in the system can present itself as a loss, but overlander is most likely right, small leaks are big problems
 

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Check the connections on the heater matrix, there is some potential you could have a leak behind
Had a similar situation several years ago and ended up being a leak at my heater matrix. It's a tough area to get a visual on. If you haven't already, take it go a good local shop and get the coolant system smoke tested.
 

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Hi Yannis,
You may have a block crack behind the timing chest, very difficult to find but you may see steam on very cold days.
The best advice i can give is to buy cooling system dye and add it to the header tank any leaks will show up under "black" light .
EG.
UV Dye & UV Torch Kit Leak Detection Dye For Cooling Antifreeze System RLD2 Ring | eBay

This will even show up if it has passed through the head into the exhaust.

Regards

Gren
 

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I would be ready to do a head gasket change, and have a good look around, a gallon of water is going to show somewhere, any raise in oil level?

36k on a disco 200 engine must be the first or second time round, unless you know the full history.

Good luck
 

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I would be ready to do a head gasket change, and have a good look around, a gallon of water is going to show somewhere, any raise in oil level?

36k on a disco 200 engine must be the first or second time round, unless you know the full history.

Good luck
In addition, the 200TDI heads are known for cracking.
You could have a crack that mostly seals when warm, but lets coolant into a cylinder when cold.
This doesn't explain itself because you have no white smoke, but something to look for if you pull for a head gasket.
 

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Check the connections on the heater matrix, there is some potential you could have a leak behind it.

Also fwiw sometimes an air bubble in the system can present itself as a loss, but overlander is most likely right, small leaks are big problems
Had a similar situation several years ago and ended up being a leak at my heater matrix. It's a tough area to get a visual on. If you haven't already, take it go a good local shop and get the coolant system smoke tested.
Heater matrix was my culprit too.
 

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Discussion Starter #12
I would be ready to do a head gasket change, and have a good look around, a gallon of water is going to show somewhere, any raise in oil level?

36k on a disco 200 engine must be the first or second time round, unless you know the full history.

Good luck
-----------------------------------------
Thanks,
No, no raise in oil level.
I know a good part of the story, this engine was on a disco in Switzerland most likely in an accident early in life but engine not affected by it. Engine ended up in a Swiss dismantling house for a few years till my friend bought it 15 years ago and stored it ever since till I got it.
 

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Ok, heater matrix possibility well taken, I'll check it even though I think it would have shown sooner or later since it is far from high heat parts and wouldn't evaporate especially now in the summer and after having consumed so many gallons of fluid.
 

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If coolant is slowly but steadily getting sipped into your pistons, intake and/or ultimately in your oil, you may not experience in any dramatic rise in oil level, like you might see in a headgasket failure, because the water in the coolant is boiled off quickly, only leaving the mineral residue in your oil. But your oil becomes caustic and starts to eat away at your crank bearings and turbo.

I would recommend replacing your oil IMMEDIATELY while youre root cause analysis is going on just in case that oil is contaminated, and then send an oil sample off. That will confirim coolant in the oil as well as abnormal residues of brass and copper from premature bearing wear.

And then of course, the standard coolant sniff tester, coolant pressure tester and compression test as all input.

If it's the heater matrix, a coolant pressure test should reveal that toot sweet, and consider yourself one lucky dude.
 

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Any sign og moisture appearing on the windshield when in Defoe mode will point to defective matrix.
 

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I couldn't figure out my coolant loss for the longest time. No steam out the tail pipe, clean oil changes, etc.... I drove for about 30 minutes to meet a friend for lunch. He wanted to see my "new" 200Tdi. When I opened the bonnet I saw a very small bit of coolant running down the bulkhead under the matrix. When I later pulled the matrix I could see that the packed mud was absorbing the bulk of the leak, masking the problem. Easier than a head gasket for sure. Hopefully this is your issue too.
 

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To rule out or confirm coolant in your oil, have a test sample taken and sent for analysis to a place like this Standard Analysis they will confirm or deny if there is coolant in your oil.

At least you can confirm at that point if you are or aren't dealing with a potential cracked head or head gasket issue.
 

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Thank you all for your thoughts, I am following up on most but some things are very time consuming.
Another thing; having stopped in a different spot and looking under the bonnet while the sunlight was directly hitting the engine I noticed some green coloring, that couldn't be seen before, on the side of the water pump flange, right along where the gasket is slightly protruding. Running a paper towel up & down, I got a lot of deep green color but dry. No wetness. Very possible that it came from evaporated coolant fluid. The deepness and the qty of the color suggests that there must have been alot of coolant evaporating at that spot but even after repeated inspections at different times with the paper I was not able to detect liquid. The gasket, which I am assuming is of paper, seems moist but that's the extend of it.
In conclusion, it seems impossible for a gallon in 10 days to be escaping from there and show no leak in the pressure test but the findings are contradicting. I will replace this gasket first and observe the change if any. My issue could be a combination of things.
I would appreciate your comments.
 

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Unlike the 300TDI, the 200 passes coolant through the front cover to the engine block which opens the possibility for multiple places for potential coolant leaks (including inside the timing gear area).

Based on the information you provided, think the best solution is tearing down the front of the engine and replacing the gaskets between the block and the front cover.

When performing this work, I replace the water pump, timing belt (and any questionable timing tensioner components), and always remove the head, have it checked for cracks, a true surface, and replace valves and guides as needed.
It is also a good idea to replace the small thermostat housing hose at a minimum.
I know you mentioned there was no pressure in the coolant system, but in my opinion, it just isn't work the risk, because any pressure will blow the front coolant gasket again and the tear down will need to be done a second time along with the head.
 

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Discussion Starter #20
Finally took the head off and had it tested (will post photos later) and it is cracked somewhere internally, it allows coolant in the exhaust. Mainly when the engine is off water enters the cylinder No3. Fortunately damage is minimal.
I am in search of a head and found HRC2123. My original is HRC2281. Anyone knows the difference? Any compatibility issues? The one I found is far from here and I don't have the chance to inspect visually.
 
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