P38, 2,5 TD, coolant / waterpump issue?

hi had same problem looked everywhere, changed all hose clamps inspected all hoses couldn't find anything. then just by chance saw a dribble above diesel pump, anyway the top radiator hose connecting pipe on the engine i found a hole right at the back underneath. pipe can be changed by the way

Update: Have changed the radiator and the thermostat yesterday night. Put a small camera into the top of the rad, could not really see anything before the middle of the rad, is the baffle in the middle of the rad? Did the marble test on both the old and the new rad. the marble did not run across on neither of the rad's. meaning that probably the "old" rad has the baffle in the right place. Which lead me towards the water pump. As the heating matrix is pouring out hot air I have reasoned that the pump is working, but could the circulation in the matrix be only water circulating by hot water being lighter than cold water?
Next will be the waterpump if it is not in good order now.
Will have to make a test run in a couple of days to see if things has come into good order.
Will keep you informed.

Larsern said:

Update: Have changed the radiator and the thermostat yesterday night. Put a small camera into the top of the rad, could not really see anything before the middle of the rad, is the baffle in the middle of the rad? Did the marble test on both the old and the new rad. the marble did not run across on neither of the rad's. meaning that probably the "old" rad has the baffle in the right place. Which lead me towards the water pump. As the heating matrix is pouring out hot air I have reasoned that the pump is working, but could the circulation in the matrix be only water circulating by hot water being lighter than cold water?
Next will be the waterpump if it is not in good order now.
Will have to make a test run in a couple of days to see if things has come into good order.
Will keep you informed.

Click to expand...

Coolant should only be circulated around the head, block and the heater until the thermostat opens.

Finally I had time for a few days work on the engine.

Went to the local stealer last fall to have a test run for CO2 in the coolant. They used a blue colored liquid that should change color to yellow if any combustion gases were present. The liquid did not change color to yellow, but I think I could see some other slight change of color. 200 £ was the bill for teaching the technician how to use the test equipment! And he didn't even manage to use it right. YELLOW color change for petrol engines, diesel should change to GREEN.
I bought a simple test set on the bay, 10 £, and tested myself, clear color change to green. (see pictures)
So, either the cylinder head or the top gasket at fault.
A good used cylinder head and a full gasket and bolt set was acquired. The head came off and did not show any signs of cracking or other faults. At first sight neither did the old gasket. Had to clean the gasket and free it from all carbon deposits before the fault appeared. A small part of the steel lining just close to a water channel was gone. The culprit found. (pict.)

The rest was just straight forward.

So the general learning from this: If you have overheating of your engine, buy yourself a test set for combustion gases in the coolant. (10£) that can save you a lot of hassle and a lot of unnecessary spare parts such as radiator, water-pump, thermostat, fan, etc.

A last tip, when using the test set, remember that the expansion container has a bypass that must be sealed temporarily for the gases to pass through the tester.

And a final thank you to all of you that have contributed to my long search for the fault.

Larsern

Well done for perservering and sharing your findings. I think if I put a new head on I'd want a new water pump and rad anyway, just for piece of mind.

Larsern said:

Finally I had time for a few days work on the engine.

Went to the local stealer last fall to have a test run for CO2 in the coolant. They used a blue colored liquid that should change color to yellow if any combustion gases were present. The liquid did not change color to yellow, but I think I could see some other slight change of color. 200 £ was the bill for teaching the technician how to use the test equipment! And he didn't even manage to use it right. YELLOW color change for petrol engines, diesel should change to GREEN.
I bought a simple test set on the bay, 10 £, and tested myself, clear color change to green. (see pictures)View attachment 129061 View attachment 129062
So, either the cylinder head or the top gasket at fault.
A good used cylinder head and a full gasket and bolt set was acquired. The head came off and did not show any signs of cracking or other faults. At first sight neither did the old gasket. Had to clean the gasket and free it from all carbon deposits before the fault appeared. A small part of the steel lining just close to a water channel was gone. The culprit found. (pict.)View attachment 129059 View attachment 129060

The rest was just straight forward.

So the general learning from this: If you have overheating of your engine, buy yourself a test set for combustion gases in the coolant. (10£) that can save you a lot of hassle and a lot of unnecessary spare parts such as radiator, water-pump, thermostat, fan, etc.

A last tip, when using the test set, remember that the expansion container has a bypass that must be sealed temporarily for the gases to pass through the tester.

And a final thank you to all of you that have contributed to my long search for the fault.

Larsern

Click to expand...

And you can always use the air lock from the test kit to make home brew. Result