Rover 220SD Water Circulation Problem

its possible that the thermostat may be faulty, even if it sometimes appears to open, so for peace of mind, and elimination purposes replace it, its not expensive, also check the radiator isnt blocked, remove top and bottom hoses and flush with a hose pipe etc, the fact that you are getting hot air from your heater vents would suggest that the water pump is working ok, its unlikely, (although don't rule this out completely) that your head gasket is leaking, these tend to be pretty durable on these engines. one last check, ensure that the return pipe to the expansion tank isnt blocked. hope this helps. steve, Oxford.

Sounds about normal. On tickover, takes ages to get heat up.

One of the things about a diesel in general is that it is hard, short of running out of water, to overheat a diesel. I have had two L series lumps so far in different cars and on both the temp gauge gets to a point just above half way and then sticks there through thick and thin, motoring or stuck for hours in roadworks, with no fan coming in at all. It's a thermal engine, it has its operating level and mostly sticks to it.

It may be possible that the thermostat is sticky, it does happen, or the temp sensor for the fan is a touch sensitive, or both. It does happen, and if it worries you so much, change the thermostat for piece of mind, but make sure you bleed the system well in the process.

PDH

Abid,

Does the temperature gauge ever go into the "red" or boiling water escape through the pressure cap when driving under normal conditions or when stopped? If the answer is no to the above, then things should be working ok. Remember, hot running engines are more efficient than cool running ones - providing they are not overheating.

The circulation of the engine puts the hot water at the top of the radiator and as it drops to the bottom the airflow cools it - so there will be a temperature difference between the top and bottom hoses and the top and bottom of the radiator.

Is the bottom pipe stone cold, or is there just a noticeable temperature difference between the two hoses when you touch them?

If the bottom pipe is stone cold, then you may have a radiator blockage - although I would then expect the engine to overheat and boil over - If it's just a noticeable difference, then all should be working OK.

That would indicate that the system is not pressurising - this could well be a faulty radiator cap or a radiator cap with a bit of dirt stuck under the seat. All water cooling systems on a car are designed to run over "atmospheric" pressure to allow a higher boiling point so that engines can run hotter and more efficiently - thus making the hoses relatively hard to squeeze at normal running temperatures (although not so hard that they cannot be compressed with strong finger pressure) - and that's why the hot water erupts explosively from the radiator cap if you take it off carelessly.

Are you losing water? If not, the head gasket is ok. Are you loosing water, but the oil level in the sump is rising? Again if no, then the head gasket is ok.

That's as it should be on a cooling system with no problems - providing it's not happening when COLD air is selected.

The electric fan is designed to switch on only if you are stuck in standing traffic, travelling very slowly for long distances, or travelling up very long, steep hills - all where there is no "ram" effect of cold air passing through the radiator at normal driving speeds. On a system that is working properly, the fan will switch on a long before the water boils and then switch off after a few minutes.

To test this, start the car and let it run at a fast idle until the fan cuts in and then stops - do this for a few "cycles" keeping an eye on the temperature guage. It should read higher than normal, but stay out of the "red" if things are ok.

A rough check of the thermostat - try starting the engine from cold and then rest your hands on the top hose which should stay relatively cool until the thermostat opens and then when it reaches working temperature, you will feel a surge of very hot water coming through the top hose.

From what you describe, I would suggest that your cooling system is generally working ok - particularly if the symptoms you describe have been there for some time and you have not experienced water loss or overheating.

I hope this is of use to you and if what I have said is incorrect, the more knowledgeable will correct me as diesels are not my forte.

Brian G

Hi All,

Thanks for your responses thus far. To answer some of your questions.

The bottom pipe is always stone cold as is the bottom of the radiator since there is no water flowing throught that bottom pipe to heat the rad. I normally do a 50 mile journey (mainly motorway mileage) to work and if i check the bottom radiator pipe its always cold. I would expect it to be slightly warm at least. I have never seen the fan come on even for a few seconds nor the bottom rad pipe warm up.

I have already back flushed the radiator and am sure there are no blockages in the rad. The return pipe is attached to a silver thing which is attached onto the engine perhaps that is blocked? But when i flushed the rad last weekend the return pipe was chucking water out when i removed it from the rad indicating the water was flowing freely and not blocked.

The temperature needle always sits slightly above half way and does not go over that no matter if I am sitting in traffic or moving.

The car is not losing water either. Ive driven it for 2000 miles or so and never once topped it up with water (its always been on the max mark). I do hear a slight hissing noise coming out of the pressure cap after I turn the engine off if i look under the bonnet. Is that normal? The oil level is steady as well not rising nor decreasing and Ive checked for oil water mix and cannot find any signs of it in the ususal places.

I will take the thermostat out this weekend and chuck it into hot water to see if it is opening or not before i replace it (almost £30 for a new one).

I have replace the coolant sensor on the engine. The fan cuts in only when you trip it by removing the wiring of the coolant sensor.

Seems like most of you guys think there is nothing wrong with the coolant system and that this is normal for a diesel engine. Perhaps. This is my first diesel car so maybe it is normal for a diesel engine to operate in this way.

Thanks for all your advice

Abid

snip|| || Thanks for your responses thus far. To answer some of your questions. || || The bottom pipe is always stone cold as is the bottom of the radiator || since there is no water flowing throught that bottom pipe to heat the || rad. I normally do a 50 mile journey (mainly motorway mileage) to || work and if i check the bottom radiator pipe its always cold. I would || expect it to be slightly warm at least. I have never seen the fan || come on even for a few seconds nor the bottom rad pipe warm up.

Motorway mileage and speeds radiator normally cool engine not working that hard everything seems normal

|| I have already back flushed the radiator and am sure there are no || blockages in the rad. The return pipe is attached to a silver thing || which is attached onto the engine perhaps that is blocked? But when i || flushed the rad last weekend the return pipe was chucking water out || when i removed it from the rad indicating the water was flowing || freely and not blocked.

That sounds OK

|| The temperature needle always sits slightly above half way and does || not go over that no matter if I am sitting in traffic or moving.

Again OK

|| The car is not losing water either. Ive driven it for 2000 miles or || so and never once topped it up with water (its always been on the max || mark). I do hear a slight hissing noise coming out of the pressure || cap after I turn the engine off if i look under the bonnet. Is that || normal? The oil level is steady as well not rising nor decreasing and || Ive checked for oil water mix and cannot find any signs of it in the || ususal places.

Again OK

|| I will take the thermostat out this weekend and chuck it into hot || water to see if it is opening or not before i replace it (almost £30 || for a new one).

If it aint broke don't fix it

|| I have replace the coolant sensor on the engine. The fan cuts in only || when you trip it by removing the wiring of the coolant sensor.

Again If it aint broke don't fix it

|| Seems like most of you guys think there is nothing wrong with the || coolant system and that this is normal for a diesel engine. Perhaps. || This is my first diesel car so maybe it is normal for a diesel engine || to operate in this way.

Yes diesels tend to run cooler than Petrols, and I have had a diesel where the rad. fan was U/S the only time the temperature rose was in traffic on a hot day (or towing) mind you I drove it all winter and changed the switch as the days got hotter!!

Again if it aint broke don't fix it!

Des

Hi,

Thanks for all your posts. Seems like it is normal for a diesel engine to behave this way after all as you guys have pointed out. After driving around town for sometime today I did hear the fan turn on only briefly though but the bottom rad pipe was warm as well. Dont know if changing the coolant sensor had anything to do with it. But hey its working so I aint gonna try breaking it.

Abid

Hi Abid,

Thanks for letting us know the outcome

Brian G