Long Term Coolant Loss

[milford man]

Had the 1.8T for nearly six years now. When I got it it had done 38,500mls and was using about a cup full of coolant every month. Could not see any external leaks so decided to do the head gasket. Fitted new head gasket (BW750) belts & water pump. Whilst the head was off I checked liner heights which were just proud of the block. 50,000mls later and it still uses about a cup full of coolant a month.

Over the years I have replaced all the rubber hoses and connections. Last year I fitted a VVC manifold. Still uses a cup full a month. Only seems to loose coolant after a series of short trips.

Yesterday after buying a pressure test kit I pumped the cooling system up to 20psi and after half an hour it had dropped to 15psi. After removing the pressure test equipment the coolant was low as you would expect as it had been pushed out somewhere. I could see no external leaks. Where the heck is it going? When I started the car it ran perfectly as it always does. If the coolant had been pushed past the head gasket or VVC manifold I would of expected it to run lumpy for a couple of minutes but it didn't. Anybody hazard a guess where it is going? I've had the bumper off in the past (several times) and can't see any leaks from the radiator.

Regards John

[T-Cut]

Water pump?
Just because you didn't mention it.

Maybe try some fluorescent dye and a UV torch. It can be handy for locating an external leak when all else fails.

http://i5.photobucket.com/albums/y191/waveguide/Cooling_System_Stuff/Fluorescent_Dye_zps2ac75286.jpg


TC

[milford man]

Yes, forgot to mention I did put a new water pump on at the time but that is now 50,000mls old. Fluorescent dye is a good idea. It does (to me) have all the hall markings of a failing water pump. When I fitted it I did not apply any RTV sealant just relied on the supplied O ring. I have read a few posts about using RTV as well.

Regards John

[roverbarmy]

Are you checking the level with the vehicle level and when cold? Are you using the correct "Max" level ( it is at the bottom of the part of the header tank that you can see)? Have you replaced the header tank cap or seals? (they are prone to leaks)
:shrug:
All worth checking before you suspect hgf problems.
Mike

[kaiser]

It could also go into the oil. At least in theory.
A small amount like that would be burnt off and would not cause any visible mayonnaise to be formed.

[T-Cut]

If you suspect the coolant is getting into the engine oil, there's a rather neat test you can do. Maybe worth trying.

The test involves placing a couple of drops of used oil on blotting paper, filter paper or even the back of a business card. The paper is left to stand for a few hours during which the lube oil will migrate outwards in a ring. If a dark or brownish stain is left in the center after the oil moves outwards, then this could be due to failing oil dispersancy and soot coagulation. This is a common effect of glycol contamination. A black sticky paste with a well-defined edge is cause for concern. Very often a soot ring develops around a yellow/brown center when glycol is present.

TC

[milford man]

Are you checking the level with the vehicle level and when cold? Are you using the correct "Max" level ( it is at the bottom of the part of the header tank that you can see)? Have you replaced the header tank cap or seals? (they are prone to leaks)
:shrug:
All worth checking before you suspect hgf problems.
Mike
Yes I am checking the level when cold and only fill it to the max level at the bottom of the tank. Over the years I have had six new caps and a new header tank. Still looses coolant. Also before I did the pressure test coolant was sitting on the max level but afterwards it was not even on the minimum. Took a good cup full to bring it up to the low level.

[milford man]

If you suspect the coolant is getting into the engine oil, there's a rather neat test you can do. Maybe worth trying.

The test involves placing a couple of drops of used oil on blotting paper, filter paper or even the back of a business card. The paper is left to stand for a few hours during which the lube oil will migrate outwards in a ring. If a dark or brownish stain is left in the center after the oil moves outwards, then this could be due to failing oil dispersancy and soot coagulation. This is a common effect of glycol contamination. A black sticky paste with a well-defined edge is cause for concern. Very often a soot ring develops around a yellow/brown center when glycol is present.

TC
I don't think it is going into the oil as the level never rises and it is not milky at all.

Regards John

[roverbarmy]

Are you getting any coolant smells/leaks from the heater matrix/hoses in the cabin area (often smells a bit like curry-strangely!)? The heat will often evaporate the coolant but leaves a stain on the carpets/in the area of loss.

[milford man]

No smells inside the car. I am going to whip the timing belt cover off to have a look at the water pump to see if that is leaking.

Regards John

[kaiser]

I don't think it is going into the oil as the level never rises and it is not milky at all.

Regards John.


The water can get into the oil and burn off, as in evaporate!
That would not cause the oil level to rise at all, neither would it cause the oil to go milky.
If the water lost is above a certain amount, then you will see it, but you are complaining about small amounts, which could disappear the way I have suggested.

[milford man]

Yes you could be right. Its a guessing game at the moment.

Regards John

[milford man]

Its the water pump. Yesterday and today stripped it down and removed the water pump. You can see pink water staining in the evap chamber and the bottom of the pump. It appears to be leaking at the bearing. This pump was a new MG Rover item when I did all the work five and a half years ago. It must of failed early on and has been getting slowly worse.

Regards John

[chipsceola]

You say "the pump was a new MG/Rover item five and a half years ago" the OEM warranty was way less than that, yet the evaporation chamber was there so that 'minor leaks' didn't cause the owner to complain to the dealership - no sight of a leak, no work required under warranty.

[milford man]

You say "the pump was a new MG/Rover item five and a half years ago" the OEM warranty was way less than that, yet the evaporation chamber was there so that 'minor leaks' didn't cause the owner to complain to the dealership - no sight of a leak, no work required under warranty.
Its not the cost of the pump its all the work required to change it. With the evap chamber you don't get to know its leaking until it gets a lot.

Regards John

[chipsceola]

Its not the cost of the pump its all the work required to change it. With the evap chamber you don't get to know its leaking until it gets a lot.

Regards John

After breakdown patrol caused HGF on my 1.8T repairs were carried out by Mike Stafford of MJS Auto and Marine from Worthing, despite existing WP having covered only 40K since earlier replacement and no signs of wear or leakage at all, a new one was fitted while easily accessible, just in case!

[milford man]

After breakdown patrol caused HGF on my 1.8T repairs were carried out by Mike Stafford of MJS Auto and Marine from Worthing, despite existing WP having covered only 40K since earlier replacement and no signs of wear or leakage at all, a new one was fitted while easily accessible, just in case!
Totally agree. I am fitting a new timing belt and tensioner while I am in there. Belt and tensioner have only just done over half their work at 50,000mls but they have to come off to change the water pump. Gone with a Circoli water pump, looks well made but we will see.

Regards John

[thegreatdaddo]

I have had exactly the same experience on my 1.8T. There is a slow loss of coolant from max to min level over a couple of months, during which I cover approximately 1,000 miles. During the last 10 years, I have changed all the likely leakage sources without making any difference. This includes replacing the reservoir cap, inlet manifold gasket, water pump, Tee piece, hose clips and head gasket (MLS replacement fitted). There is no sign of an external leak and no obvious sign of the coolant getting into the oil. Since this problem seems to affect the 1.8T, I am starting to think that the coolant may be leaking from the turbo charger, which is connected to the engine coolant circuit. I have not had to change it yet. Maybe one of the club members who has disassembled a turbo can comment on whether there was any sign of coolant leakage?

[milford man]

I have had exactly the same experience on my 1.8T. There is a slow loss of coolant from max to min level over a couple of months, during which I cover approximately 1,000 miles. During the last 10 years, I have changed all the likely leakage sources without making any difference. This includes replacing the reservoir cap, inlet manifold gasket, water pump, Tee piece, hose clips and head gasket (MLS replacement fitted). There is no sign of an external leak and no obvious sign of the coolant getting into the oil. Since this problem seems to affect the 1.8T, I am starting to think that the coolant may be leaking from the turbo charger, which is connected to the engine coolant circuit. I have not had to change it yet. Maybe one of the club members who has disassembled a turbo can comment on whether there was any sign of coolant leakage?
In my case its the water pump. My mistake was assuming the pump was good as I replaced it when I first got the car. I reckon it started leaking within 5000mls of use. It was a genuine MG Rover one too. Rover designed an evaporator chamber to hide leaking pumps. They couldn't seem to design one that didn't leak. All down to cost I guess.

Regards John

[T-Cut]

I am starting to think that the coolant may be leaking from the turbo charger, which is connected to the engine coolant circuit.

It is, but impossible for coolant to leak into the engine unless the tubocharger body is cracked. There are no water seals like those in the water pump. The cooling jacket is a closed cavity with inlet/outlet drillings from the outside. There's no contact with the rotating parts.

TC

[milford man]

Just finished the fitting of the new water pump also fitted new timing belt and tensioner. Done a pressure test and its holding. Lets hope that sorts it. Will see how long this pump lasts. I hope its the last one I fit as my back is not what it used to be.

Regards John