MY WIFE HAS A

[tuscan66]

rover 75 ita a 04 facelift 1.8 turbo now and then the temp gauge will rise from normal midway to high in a matter of seconds fans kick in quite often even at normal temp water levels all good are we looking at a poss sensor/ sender fault ?? many thanks

[restoman]

Are you actually losing any coolant?

[Liquid Knight]

Take the thermostat out and put it in the bin. Best place for them. If you replace it you will only cure the problem for a short while befor it goes wrong again.

If you insist on having a 'stat try to put filtered water into the engine. Like washing machines limescale builds up on the thermostat and chuffs it only you can't put de-scaler in an engine safely.

[tuscan66]

restoman said:

Are you actually losing any coolant?

no coolant loss will have the stat out and see how it looks and as suggested bin at least for the summer

[jith]

Liquid Knight said:

Take the thermostat out and put it in the bin. Best place for them. If you replace it you will only cure the problem for a short while befor it goes wrong again.

If you insist on having a 'stat try to put filtered water into the engine. Like washing machines limescale builds up on the thermostat and chuffs it only you can't put de-scaler in an engine safely.

Wrong! wrong! and wrong again.

Correct coolant temperature is absolutely vital. Running the engine too cool will affect your lubrication as the oil never reaches correct operating temperature, it will drastically reduce the life of the lambda sensors and cats and will result in excess fuel consumption due to over-fuelling.

You must NEVER run the cooling system on anything other than the correct mix of ant-freeze. Failing to do so will result in the radiator and heater matrix corroding internally.

J

[MGJohn]

jith said:

Liquid Knight said:

Take the thermostat out and put it in the bin. Best place for them. If you replace it you will only cure the problem for a short while befor it goes wrong again.

If you insist on having a 'stat try to put filtered water into the engine. Like washing machines limescale builds up on the thermostat and chuffs it only you can't put de-scaler in an engine safely.

Wrong! wrong! and wrong again.

Correct coolant temperature is absolutely vital. Running the engine too cool will affect your lubrication as the oil never reaches correct operating temperature, it will drastically reduce the life of the lambda sensors and cats and will result in excess fuel consumption due to over-fuelling.

You must NEVER run the cooling system on anything other than the correct mix of ant-freeze. Failing to do so will result in the radiator and heater matrix corroding internally.

J

Spot on advice from jith.

However, there's still a problem. Has the OP's car had any work on it recently? Particularly involving disturbing the cooling system in any way.

Bearing in mind no coolant losses ( are you really certain ? ), I suspect there's an Air Pocket still in the cooling system. Bleeding the sophisticated little K-Series is tricky at best and if not bled correctly, the engine temperature gauge will behave exactly as you described.

If this is what is happening to your car and all other things are fine, search over on MG-Rover.org for 'how to' bleeding Rover's K16 ...

Also, when was the last time your car's cooling system had a thorough flush and replenished with correct 50-50 OAT antifreeze mix? Doing this properly can transform how an engine behaves.... not just Rover engines.
..

[tonys]

MGJohn said:

jith said:

Liquid Knight said:

Take the thermostat out and put it in the bin. Best place for them. If you replace it you will only cure the problem for a short while befor it goes wrong again.

If you insist on having a 'stat try to put filtered water into the engine. Like washing machines limescale builds up on the thermostat and chuffs it only you can't put de-scaler in an engine safely.

Wrong! wrong! and wrong again.

Correct coolant temperature is absolutely vital. Running the engine too cool will affect your lubrication as the oil never reaches correct operating temperature, it will drastically reduce the life of the lambda sensors and cats and will result in excess fuel consumption due to over-fuelling.

You must NEVER run the cooling system on anything other than the correct mix of ant-freeze. Failing to do so will result in the radiator and heater matrix corroding internally.

J

Spot on advice from jith.

However, there's still a problem. Has the OP's car had any work on it recently? Particularly involving disturbing the cooling system in any way.

Bearing in mind no coolant losses ( are you really certain ? ), I suspect there's an Air Pocket still in the cooling system. Bleeding the sophisticated little K-Series is tricky at best and if not bled correctly, the engine temperature gauge will behave exactly as you described.

If this is what is happening to your car and all other things are fine, search over on MG-Rover.org for 'how to' bleeding Rover's K16 ...

Also, when was the last time your car's cooling system had a thorough flush and replenished with correct 50-50 OAT antifreeze mix? Doing this properly can transform how an engine behaves.... not just Rover engines.
..

+1, my first thought was an airlock.

[tuscan66]

air lock but only small seems all sorted now been ok for near 2 weeks amaizing the cause and effect it had.. thanks all

[MGJohn]

tuscan66 said:

air lock but only small seems all sorted now been ok for near 2 weeks amaizing the cause and effect it had.. thanks all

Good news ~ keep an eye on things anyway, just in case.

The 1.8 K-Series Turbo is a sophisticated little engine with remarkable output for size. I emphasize LITTLE and in the 75 or ZT it is punching well above its weight which it does well most of the time if maintained correctly.

It is essential that the cooling system is bled correctly. Sometimes this is very difficult to do because with age and maybe poor coolant servicing, the 'Jiggle valve' in the Inlet manifold gets completely blocked with coolant system crud and then bleeding the system is difficult or hit and miss at best even in the best run workshops.

Had the same problem with a "They all do that" Rover project and Inlet Manifold removal and cleaning out the "Jiggle Valve" resulted in immediate correct coolant bleed. No problem since.

Here's what a clean Jiggle Valve looks like. If that little ball bearing becomes blocked with crud it will never allow air to escape out of the head into the expansion Bottle. That's when the overheating happens and that can damage engine components, the first to be damaged is usually the cylinder head gasket.



It's little things like this which makes all the difference... in any car.

Hope this helps anyone else when faced with a similar problem.
.

[tonys]

MGJohn said:

tuscan66 said:

air lock but only small seems all sorted now been ok for near 2 weeks amaizing the cause and effect it had.. thanks all

Good news ~ keep an eye on things anyway, just in case.

The 1.8 K-Series Turbo is a sophisticated little engine with remarkable output for size. I emphasize LITTLE and in the 75 or ZT it is punching well above its weight which it does well most of the time if maintained correctly.

It is essential that the cooling system is bled correctly. Sometimes this is very difficult to do because with age and maybe poor coolant servicing, the 'Jiggle valve' in the Inlet manifold gets completely blocked with coolant system crud and then bleeding the system is difficult or hit and miss at best even in the best run workshops.

Had the same problem with a "They all do that" Rover project and Inlet Manifold removal and cleaning out the "Jiggle Valve" resulted in immediate correct coolant bleed. No problem since.

Here's what a clean Jiggle Valve looks like. If that little ball bearing becomes blocked with crud it will never allow air to escape out of the head into the expansion Bottle. That's when the overheating happens and that can damage engine components, the first to be damaged is usually the cylinder head gasket.



It's little things like this which makes all the difference... in any car.

Hope this helps anyone else when faced with a similar problem.
.

Top post that man!