perennial V6 petrol overheating dilemma

[SideValve]

Nothing to do with the overheating but regarding the water loss - could you be overfilling it? The proper level is pretty low so easily done.

Have you checked the fan by trying the demist test?

[Theodore]

Originally Posted by SideValve

Nothing to do with the overheating but regarding the water loss - could you be overfilling it? The proper level is pretty low so easily done.

Have you checked the fan by trying the demist test?

Now there's a thing. I've never actually been able to see where the max and min gauge is on the tank. So, I usually fill to the top. Now, you've got me thinking could the fluid I saw be overspill? I did once see steam escaping from somewhere on the expansion tank either from the cap - brand new - or the small tube by the cap....this wouldn't explain the overheating but might explain the fluid loss on this particular occasion. On other occasions however, I've had to pour in nearly a litre and half, so no idea where it goes, can it evaporate?
no, never done the demist test. will try

[topman]

Originally Posted by Theodore

So, I usually fill to the top.

Right to the top of the neck? There's a picture on here about how high to fill it. It's not as high as you think.

[Bolin]

Is it a buff tank? There are marking on the side, shine a light (phone torch) against it to see the level. Far better than the tab inside I think, you can check the level without removing the cap (unlike the black tank).

[Theodore]

Originally Posted by topman

Right to the top of the neck? There's a picture on here about how high to fill it. It's not as high as you think.

Er,possibly....

Originally Posted by Bolin

Is it a buff tank? There are marking on the side, shine a light (phone torch) against it to see the level. Far better than the tab inside I think, you can check the level without removing the cap (unlike the black tank).

We love this car, but sweet Jesus, it says something when you cannot even fill the expansion tank correctly because you cannot see the markings! And whilst we're on it and off topic: changed my dipped light yesterday - about all I could do - it worked...hoorah. Today it doesn't and it never even left the drive!!!

[murphyv310]

Hi.
Well you have a list of to do's!
Once you have done them all should be fine, don't skip any though or you will be back to square one.
Firstly check your fan and make sure it works as it should, The demist test will tell you as will switching on the aircon to auto and setting the temperature's on one or both sides to say 20, the radiator cooling fan should run at slow speed continuously and not pulse on the faster speed. If you have a pulsing fan it's most likely the silver resistor at fault (open circuit). The cure is to replace it with a "Gold" resistor that can handle the current better as it is rated at double the wattage.

Next is to flush out the full cooling system, use Holts speedflush but leave it in for a day and try and run the car about if you can, then dump all the coolant by removing the hose at the bottom of the radiator, also remove the drain "bolt" from the engine block to drain it too. Get plenty of water through the system to flush out the old coolant and speedflush. While you still have the bottom hose off and the block drain still out, remove the heater matrix and flush it out properly in the sink, as you live in London use some de-scale fluid to remove the calcium build up.
While your in the mood I'd also recommend changing the thermostat as it may well be sticking shut giving you the intermittent overheating.
As has been said look carefully at the coolant rail steel pipes under the radiator, these are rubbish mild steel pipes and rust badly.
Others may disagree but mine along with the oil cooler are bypassed and will not be refitted, an infra-red thermometer I've used after a fast run has never been above 103c and mostly sits at 95 after about 20 minutes running.

You can do all of this over a weekend or in stages which will possibly tell you what is wrong but I really think you have multiple problems so better to tackle it in one go. For reliability I would never drive a car if there is a possibility of an overheat, it does the engine no favours, I really think you should get the work done post haste!
Good luck

PS.
Don't overfill the system and make sure you bleed it properly as per the MGR rules, use distilled water and antifreeze between 33-50% antifreeze, don't use tap water.

[Theodore]

Originally Posted by murphyv310

Hi.
Well you have a list of to do's!
Once you have done them all should be fine, don't skip any though or you will be back to square one.
Firstly check your fan and make sure it works as it should, The demist test will tell you as will switching on the aircon to auto and setting the temperature's on one or both sides to say 20, the radiator cooling fan should run at slow speed continuously and not pulse on the faster speed. If you have a pulsing fan it's most likely the silver resistor at fault (open circuit). The cure is to replace it with a "Gold" resistor that can handle the current better as it is rated at double the wattage.

Next is to flush out the full cooling system, use Holts speedflush but leave it in for a day and try and run the car about if you can, then dump all the coolant by removing the hose at the bottom of the radiator, also remove the drain "bolt" from the engine block to drain it too. Get plenty of water through the system to flush out the old coolant and speedflush. While you still have the bottom hose off and the block drain still out, remove the heater matrix and flush it out properly in the sink, as you live in London use some de-scale fluid to remove the calcium build up.
While your in the mood I'd also recommend changing the thermostat as it may well be sticking shut giving you the intermittent overheating.
As has been said look carefully at the coolant rail steel pipes under the radiator, these are rubbish mild steel pipes and rust badly.
Others may disagree but mine along with the oil cooler are bypassed and will not be refitted, an infra-red thermometer I've used after a fast run has never been above 103c and mostly sits at 95 after about 20 minutes running.

You can do all of this over a weekend or in stages which will possibly tell you what is wrong but I really think you have multiple problems so better to tackle it in one go. For reliability I would never drive a car if there is a possibility of an overheat, it does the engine no favours, I really think you should get the work done post haste!
Good luck

PS.
Don't overfill the system and make sure you bleed it properly as per the MGR rules, use distilled water and antifreeze between 33-50% antifreeze, don't use tap water.

You sure you haven't missed anything? Kidney removal? Someone posted somewhere on here, 'you never see Rovers on the hard shoulder, just German cars', there's a reason, the Rovers are stuck on the drives constantly being repaired!

[murphyv310]

Originally Posted by Theodore

You sure you haven't missed anything? Kidney removal? Someone posted somewhere on here, 'you never see Rovers on the hard shoulder, just German cars', there's a reason, the Rovers are stuck on the drives constantly being repaired!

Ha Ha.
Most likely the Rovers have had indifferent servicing in their lives. I wonder how many Rover dealers lost heart, went bust or did rotten jobs when MGR shut shop, TBH the cars don't really have a chance in those circumstances plus the youngest is 11 years old now.
They are actually not that hard to work on in comparison to today's offerings.

[genpk]

When you look into the top tank you will see "Max" stamped into the plastic bottom,water should be just covering that. Much more water than that and you will have water being pushed out of the system when warm (probably via the radiator cap" ) and may think you have issues you dont.
The advice re doing a flush of the whole system is good as at least you know the quality of the coolant in the system and it may also free up, get rid of anything in the system causing issues.
The heater bloackage will not cause you car to overheat on its own although if blocked somone may have put somthing in the system to try and fix another issue such as a leak.
As said, you can flush the heater matrix out via heater hoses in the engine bay although fiddly not as bad as removing the matrix itself.

[SD1too]

Theodore,

1. You're overfilling your expansion tank and you may have air in the cooling system. Give your garage this guide and ensure that the level is no higher than the 'max' tab inside the tank.
2. Start the engine from cold, press 'demist' and check that the radiator fan is running continuously.
3. Use this to monitor the actual coolant temperature.
4. Report back with the results.

Simon