Apologies for the long post

1. First noticed that the heater in the cabin was blowing cold air when the internal temperature was set to high. On checking coolant level in radiator noticed that it was dry and the reservoir was between min and max. topped up radiator and the internal heater started functioning again. Noticed that the passenger side was hotter than drivers side. This was on the way home after buying the vehicle.

2. On first journey of approx. 30 miles vehicle was overheating and went into limp mode. Mobile mechanic was called out and inspected vehicle and said that the coolant level needed topping up with 3 ltrs of antifreeze and that the thermostat housing was cracked, an onsite repair was carried out ( jb weld) to the housing. After the return journey the coolant level was checked and noticed coolant on the inner wing below the reservoir which was full. The radiator required again topping up.

3. The temporary fix to the thermostat housing showed no signs of leakage a new thermostat housing and gasket was installed. After a test run ( 5 Miles) coolant was once again present on inner wing and reservoir was full. Radiator level checked and no coolant visible in radiator.

4. Thermostat and radiator cap replaced still same symptoms of coolant overflow after test run. Using an anti-spill funnel in the radiator and running the engine bubbles were present in the coolant. The level of the coolant changed before the thermostat was open and fluctuated whilst the engine was running.

5. A sniff test was carried out to determine whether a head gasket issue was the cause, the test provided a negative reading. Even though a negative reading, the egr cooler and heater matrix were bypassed and bubbles were still present in the coolant in the anti-spill funnel. No visible leaks from hoses/ radiator etc. To confirm a local garage conducted a sniff test also and bypassed the egr and heater matrix and confirmed a negative reading.

6. The coolant system has been extensively flushed and treated with a head gasket /block sealant in an effort to rectify the problem. Bubbles continue to be present and pressurizing of the system causes the system to overflow.
The local mechanic is stumped as am I and any help/advice on this matter would be greatly appreciated.

 

Something to keep in mind,
Combustion chamber pressure is much much higher than any pressure provided by a coolant system tester.

Is any white smoke visible from the exhaust when the engine is running? If so , it could confirm a possible head gasket problem or more.
I would think some disassembly will be necessary to confirm what we believe could be the problem.
The bubbles into the coolant is a tip off of combustion pressure getting into the coolant.
This can get pretty expensive to correct.

 

There is a little white smoke, at start up , probably only burning off condensation out of the exhaust. soon clears.
The bubbles in the coolant, we believe is combustion pressure, but are baffled because the combustion gas test comes back negative time and time again.
One theory is that there is a small hairline crack in one ore more of the cylinders, below the point when the piston is on its downward stroke and the exhaust valve is open.
The next step I am going to take is to try and remove the injectors one by one and run the engine between injector pulls, to try and identify which cylinder/s may be causing the combustion pressure.
If the bubbles stop after pulling out an injector, on that cylinder. This might give me a clue as to were the problem lies.
I believe pulling the injector will be easier than gaining access to the glow plugs too.

 

Diesels have a tendency to burn oil up the road if severely overheated. Until we know exactly where we are,best to take one thing at a time.

We don't know if it was overheated or anything more for that matter. Looks like you know what you need to do, can you keep us updated with what you find, thanks?

 

Well, pulling the injector was a mistake.
After removing the injector clampdown bolt - ensure you have a magnetic retreival tool to hold the clamp, before removing the injector. If this falls into the head it can be difficult to retrieve without removing the rocker cover. After pulling the injector replace the clampdown bolt to prevent it falling..
Cranking / running the engine with the injector removed, will spray oil all over the engine bay / bonnet. The oil is picked up from under the rocker cover.
I stopped after only pulling one injector, and one short engine run on 3 cylinders. Due to the mess, I was unable to check if that cylinder was the problem.

Any suggestions on how to do this without making such a mess.