Strange cooling problem

[martini_zupa]

Disco 300tdi, heating does not work, cooling sometimes does, sometime does not. Yesterday replaced thermostat, filled up the system with coolant to level, with semi-warm engine it worked well (heater worked, cooling also was OK). This morning the old story - heating does not work, cooling was working. Coolant pipes are tense, there is pressure in the system.

Few days before heater was not working, I managed to overheat engine a bit (temp gauge was in red when I noticed the smell of coolant), the coolant blew out of the reservoir, yet the engine survived (no banging). Fiddled with filling up the coolant, checked that it did get into heater - all OK, cooling works, heater also works.
At this point I have no idea what could be the problem. This started about a week ago (only the heating was not working for some time after starting the car and then at some point with already normal running temperature the heating suddenly starts to work at full). Could it be the head gasket? Anything else? How to check?

[ComicalEngineer]

Most probably head gasket.

TDI engine doesn't take kindly to overheating!

[thebiglad]

Disco 300tdi, heating does not work, cooling sometimes does, sometime does not. Yesterday replaced thermostat, filled up the system with coolant to level, with semi-warm engine it worked well (heater worked, cooling also was OK). This morning the old story - heating does not work, cooling was working. Coolant pipes are tense, there is pressure in the system.

Few days before heater was not working, I managed to overheat engine a bit (temp gauge was in red when I noticed the smell of coolant), the coolant blew out of the reservoir, yet the engine survived (no banging). Fiddled with filling up the coolant, checked that it did get into heater - all OK, cooling works, heater also works.
At this point I have no idea what could be the problem. This started about a week ago (only the heating was not working for some time after starting the car and then at some point with already normal running temperature the heating suddenly starts to work at full). Could it be the head gasket? Anything else? How to check?

Hi there, here is a list of things to check:

1. Is she losing water ie are you having to top her up a lot?

2. Whilst the engine is running, CAREFULLY remove the header tank cap and watch the water level, are there any bubbles in it? If there are, does it increase with engine revs?

3. Take off the oil filler cap and see if there is any gloopy stuff there - looks a bit like mayonnaise?


Can't think of anything alse at the mo

Cheers & good luck

Dave

[martini_zupa]

It started before overheating. Before that it was never overheated for the time this car is mine (not sure about previous owner, it seems he was lying about everything). Yet I've also think this should be gasket, since there is also a tiny clicking noise in the rhythm of one cylinder under load.

About overheating - we managed to overheat our race Defender 300tdi, the temperature gauge went in red, went out of red on the other side, then met the end of the gauge and then cooled down. After that when engine still was hot we had problems starting it. Later there was banging, clicking etc, but because that happened shortly before going to Ladoga trophy we didn't have enough time to repair it. Banging and clicking and making a lot of smoke we finished Ladoga, came home, participated in next Latvian trophy raid championship stage, then repaired the engine and found a dead fish under the engine (must be from Ladoga) :D. Now it is repaired and tweaked, runs very well. So, yes, they don't like overheating, but even overheated and half-broken they still run...

[martini_zupa]

Hi there, here is a list of things to check:

1. Is she losing water ie are you having to top her up a lot?

2. Whilst the engine is running, CAREFULLY remove the header tank cap and watch the water level, are there any bubbles in it? If there are, does it increase with engine revs?

3. Take off the oil filler cap and see if there is any gloopy stuff there - looks a bit like mayonnaise?


Can't think of anything alse at the mo

Cheers & good luck

Dave
1. A bit, not much
2. Is not possible, the tank usually is full with coolant and under pressure (yet I fill it up only up to the required level when cold, remove the air usually), the pressure builds up quite fast with engine a bit warm.
3. No, checked that earlier already.

Talked with several known good mechanics also, they say that it should be the gasket, so I've scheduled a head grinding/gasket change, will report about the results. Judging from what I have seen until now with this car it is possible that the ***** who repaired the engine (seller said engine was overheated and had full renovation done by his mates, which "are good") have put in the old gasket (how clever you have to be not to change rear output seal and all the other seals if the engine is overheated, being renovated and taken out of the car, they have changed nothing).

Thanks for ideas!

[littlelegs]

Disco 300tdi, heating does not work, cooling sometimes does, sometime does not. Yesterday replaced thermostat, filled up the system with coolant to level, with semi-warm engine it worked well (heater worked, cooling also was OK). This morning the old story - heating does not work, cooling was working. Coolant pipes are tense, there is pressure in the system.

Few days before heater was not working, I managed to overheat engine a bit (temp gauge was in red when I noticed the smell of coolant), the coolant blew out of the reservoir, yet the engine survived (no banging). Fiddled with filling up the coolant, checked that it did get into heater - all OK, cooling works, heater also works.
At this point I have no idea what could be the problem. This started about a week ago (only the heating was not working for some time after starting the car and then at some point with already normal running temperature the heating suddenly starts to work at full). Could it be the head gasket? Anything else? How to check?

Do you know why it overheated originally? A very common and overlooked problem is a partially blocked radiator which once started will continue. Another problem is insufficient venting but this of course could be because of a leaky head gasket. Despite what is said I've always found the 200 and 300TDI to be just as robust as any other engine and overheating as apposed to running without coolant to not be a particular problem or harmful. If the temperature rises under load then it could be either the rad or head gasket as the symptoms but not causes are similar. If it requires venting after running ok without overheating then probably it's the gasket letting gasses in.

[martini_zupa]

Do you know why it overheated originally? A very common and overlooked problem is a partially blocked radiator which once started will continue. Another problem is insufficient venting but this of course could be because of a leaky head gasket. Despite what is said I've always found the 200 and 300TDI to be just as robust as any other engine and overheating as apposed to running without coolant to not be a particular problem or harmful. If the temperature rises under load then it could be either the rad or head gasket as the symptoms but not causes are similar. If it requires venting after running ok without overheating then probably it's the gasket letting gasses in.

No, don't know why it was overheated. The car is originally from Italy, it was overheated there. Until now (and it has been about half a year since bought this car) there were no problems with cooling and heating, have towed about a ton at some 60-70mph - not a sign of overheating. I think if the head is not bolted tight enough, then it could slowly blow out a path for gases.

[ComicalEngineer]

Littlelegs is correct. You need to find the cause of the overheating. Discos are over-cooled generally and a rising temperature gauge is a sign of a problem somewhere in the cooling system.

I would start by checking the thermostat. This is cheap and quick to do and you will want a new one anyway if the engine has overheated.

Then: radiator not clogged (inside or out). Fins can corrode outside and corrosion can clog water passages inside. If either of these then get a new rad. Not too expensive and easy to do.

Is the rad clogged with mud outside? This is also a common problem especially if you've been offroading. Another easy fix!

Then you're down to water pump. Slightly more difficult to do but not too bad and relatively cheap.

There is no point skimming the head unless you cure the cause as it will just fail again!

[martini_zupa]

Littlelegs is correct. You need to find the cause of the overheating. Discos are over-cooled generally and a rising temperature gauge is a sign of a problem somewhere in the cooling system.

I would start by checking the thermostat. This is cheap and quick to do and you will want a new one anyway if the engine has overheated.

Then: radiator not clogged (inside or out). Fins can corrode outside and corrosion can clog water passages inside. If either of these then get a new rad. Not too expensive and easy to do.

Is the rad clogged with mud outside? This is also a common problem especially if you've been offroading. Another easy fix!

Then you're down to water pump. Slightly more difficult to do but not too bad and relatively cheap.

There is no point skimming the head unless you cure the cause as it will just fail again!

Thermostat - as I said ir first post - new since yesterday, did'nt help.
Pump - new, using until now for two months, is OK.
Radiator is not clogged, anyway that would produce rising temperature, but not stopping heater from heatingh anyway (at lest until coolant starts to boil).

[thebiglad]

Have you checked throoughly to ensure that there are no airlocks in the system? Did you refill via the plastic plug on top of the radiator and the thermostat housing?

A classic symtom of airlock is the fact that the in-car heater is not working correctly.

Cheers & good luck

Dave

[martini_zupa]

Of course, did all that. I open the plastic plug in the thermostat's case, then fill up system, after that I even force a little bit of pressure in the filling tank to get all the air out.

Did also some experiments yesterday and it seems that the head gasket has a micro crack or something, because I'm not loosing coolant and mostly system works. What I did: opened the cooling system at warm engine, filled up, let air out etc, all works, cooling works, heating also works. After that had to drive for several hours, tried to use low revs as much as possible (trying not to blow the gasket too much). After that car was not driven for 9 hours, it was dead cold after that. Even when the car was cold there was pressure in the cooling system, where at such combination (open system when its hot, close it, cool down) there should bee a little vacuum.

Then another experiment: looking for bubbles. Again had to remove air from system, engine runs normally at idle speed - no bubbles in tank. Press the accelerator (actually the lever at the pump) slowly - no bubbles. Sudden and quick "pedal to the metal" - there are quite lot of bubbles. So, this morning the car was left for head skimming/gasket change. Will see if that helps.

All this is enough small, if there were obvious signs, like emulsion on the oil filler cap - no questions, goto workshop, but this is sort-of-like something, it is hard to find the cause... :)

Will report at the end of the week or at the beginning of the next week, I'm having the car back on Friday.

[xsalonx]

hello.. i have been reading these posts and i am haveing the same troubless. how exactly do you get rid of the air lock?? my friend has found one bleeder valve on pipe but is there more?

[martini_zupa]

Stand in front of the engine, there is a cubic little box, with pipes connected. Thats where the thermostat lives, this box has plastic plug, 19mm or 22mm bolt. Look at his thread: http://forums.lr4x4.com/index.php?showtopic=10681, first picture, in the center there is black plastic bolt, unbolt it, open cooler eexpansion tank, fill it up to the level if needed, probably will have help the air get out by blowing a bit of air in the tank to make it press out the air.

But, if you do that, the system works well and next day again it is not working - there could be a bigger problem.

[rocky 1]

Hi, I had exactly the same problem. Heater would work one day and not the next. changed the thermostat etc., but it gradually go worse--overpressuring the system. It eventually turned into a gusher. I took off the head and found the gasket was leaking between no. 1 & 2 and 3 & 4 cylinders.
Took the head to get it checked, wasn't cracked but it did need skimming. Put it all back together and it's been fine since. If you do get the head skimmed make sure that the valve stand down is checked, because if there is too muck taken off the the valves and the injectors will hit the pistons resulting in a lot of damage. Also check that the engine block is level and true.
if it is the gasket then use a genuine landrover gasket, these are far superior to any pattern part and make sure that the head is tightened down as per the manual.
Good luck, Rocky 1

[martini_zupa]

Called the mechanic, he confirmed that gasket was leaking between cylinders. Also there is an external oil leak and a bit of coolant, so the whole front must be removed (so will check the timing belt, tensioners, idlers etc). The just got welded (it seems that it was skimmed too much between cylinders), now it will be skimmed to the level.

In the meantime there are news, mostly applies to Latvians, Lithuanians, Estonians maybe, anyone who lives enough close to Lithuania: don't buy cars in Lithuania if you don't know the seller. You will be robbed. The mechanic said got now a car just bought in Lithuania, Disco 2, client reported some problems. The mechanic looked under the car, and there is the new trend in clutch changing: f*** the whole bolting thing, just take grinding tool (angle grinder?) an saw a hole in the gearbox, change everything through the hole. F**** Lithuanian ****holes (sorry Lithuanians, it refers only to those idiots who prepare the cars for sale this way)! Hope to receive my car tomorrow, will make some pictures of this "artwork" if it will be there. My tip - go to Italy and you will probably find a Disco without any body rust (mine has zero, is from Italy, they do not use salt on roads because there is no need for it) but probably overheated engine, or Germany. Once again it is confirmed: they actually can make a BMW from two crushed Audi's, only the new car will run at least several miles, after that it is pure lottery.