Any - Coolant changes - Andrew-T

My Pug 207 diesel (1.6 HDi) is approaching its 8th birthday, and as advised in the maker's handbook, it still runs with the original engine coolant, which is still clear blue in the reservoir - though it is now just about at the MIN mark when cold.

Would this also happen in a light-alloy block? I'm a bit surprised that there has been no discolouration in a steel one.

Any - Coolant changes - Cyd

It's the anti-corrosion package that gives coolant its useful life. So it's clearly still doing its job, but should be changed before it fails.

If you are DIYing make sure to buy deionised water rather than using tap water.

Any - Coolant changes - madf

The 10 year OAT coolant in our Yaris D4D with alloy block was perfectly pink with no corrosion when I changed it.
Any - Coolant changes - Wackyracer

Did you use genuine Toyota coolant or an aftermarket one Madf?

Any - Coolant changes - John F

Although Ford say renew coolant after 10yrs, I have not done so as it still looks beautifully clear and pink and has never ever required a top up in all the 11 years we have had it. It is now 15. When cold it is on the minimum mark and goes above this when warm.

Corrosion can only take place when oxygen is present so once this is used up, no further corrosion can happen. This is why my records show I last drained and flushed my TR7 in 1986 before I realised the futility of doing so. When the water pump failed in 2002 I even kept and filtered the coolant I had to drain off to change it and reused it. It is now 35yrs old and so far all parts of the cooling circulation, including the heater matrix and all rubber pipes and joints, are original and continent. The cylinder head has never had to be removed to change a corroded gasket - indeed, I suspect it would now be virtually impossible to do so if and when it eventually fails.

In theory, the best water to use would be rainwater from a fishtank deoxygenated by the fish!

Any - Coolant changes - ohsoslow

In theory, the best water to use would be rainwater from a fishtank deoxygenated by the fish!

Ready to be shot down here..........

Many fish tanks / ponds have air pumped through them and / or oxygenating plants to provide oxygen for the fish which is extracted through their gills.

Any - Coolant changes - Chris M

If the fish had successfully deoxygenated the water, they would be dead!

Any - Coolant changes - Andrew-T

If the fish had successfully deoxygenated the water, they would be dead!

Quite so. And even if not, I don't think I would risk it in my cooling circuit for 10 days, never mind years ....

Any - Coolant changes - John F

If the fish had successfully deoxygenated the water, they would be dead!

Quite so. I didn't want to antagonise the animal rights brigade with precise details!

Any - Coolant changes - thunderbird

Older type antifreeze looses its corrosion protectection properties after a couple of years which is why it should be replaced.

Modern antifreezes are much better and last longer but still need replacing at the recomended intervals.

To re-use coolant after engine work is just plan daft, compared to the cost of a new engine its a minor expense, less than a tank of petrol.

I have always repalced the coolant at the correct intervals and will continue to do so. Correct maintenance is part of your car ownership costs. If you don't want to do it fair enough but I always pitty the buyer of some ill maintained cars.

Any - Coolant changes - John F

To re-use coolant after engine work is just plan daft

No need to be rude.

You either didn't read my reasoning, or didn't understand it. Please argue intelligently, e.g. a detailed chemical explanation of how anticorrosion properties are 'lost' after 2yrs. If your arguments make enough sense and carry enough weight I will change my mind.

As for poorly maintained - I wonder how many other 35yr old TR7s are in as good original nick as mine with uncorroded engines and ancillaries?

Any - Coolant changes - Andrew-T

<< Please argue intelligently, e.g. a detailed chemical explanation of how anticorrosion properties are 'lost' after 2yrs. If your arguments make enough sense and carry enough weight I will change my mind. >>

I would also consider the small saving by re-using coolant not worth the possible downside. Mainly, how do you make sure it stays uncontaminated before you put it back in? Surely you don't filter it?

Any - Coolant changes - John F

. Mainly, how do you make sure it stays uncontaminated before you put it back in? Surely you don't filter it?

No need to filter. I poured it from washing up bowl into a bottle, left it to settle, then decanted it like a fine claret.....which is a good source of enjoyment on which to spend the money saved by such wise thriftiness;-)


Any - Coolant changes - Wackyracer

. Mainly, how do you make sure it stays uncontaminated before you put it back in? Surely you don't filter it?

No need to filter. I poured it from washing up bowl into a bottle, left it to settle, then decanted it like a fine claret.....which is a good source of enjoyment on which to spend the money saved by such wise thriftiness;-)


There is the other concern that when the coolant was draining it might have come into contact with a surface of engine or chassis which has traces of dissolvable contaminants such as road salt or oil.

Any - Coolant changes - MrEckerslikefromRamsbottom

I live in an old and damp terraced house. I use a de-humidifier. The water collected by the de-humidifier is what I used to replace the coolant after my thermostat housing sprung a leak and I had to fit a new one.

Any - Coolant changes - Andrew-T

The water collected by the de-humidifier is what I used to replace the coolant after my thermostat housing sprung a leak and I had to fit a new one.

You make it sound like wartime. I would guess a bottle of deionised (not expensive) would be cleaner than what dribbles off your dehumidifier ?

Any - Coolant changes - Wackyracer

I would guess a bottle of deionised (not expensive) would be cleaner than what dribbles off your dehumidifier ?

I guess your right at a couple of quid for a gallon.

Any - Coolant changes - quizman

I'm with John F on this, use the same antifreeze for the lifetime of the car and if you need some for top ups what's wrong with getting some from you local scrapyard out of a scrapped car? Plenty good enough.

It's like new tyres, get the cheapest Chinese rubbish you can find or of course go to your local scrapyard, plenty of choice there.

Oil, go to Wilcos and buy some 20W/50 for £2 a gallon, none of this expensive synthetic stuff for us clever savers. Or try the local etc......

Water,what's wrong with good old tap. I went for a meal the other night and they tried to sell me some fancy bottled stuff. You must be joking said I, tap water is good enough for me and put some ice and lemon in while you're at it.

Some folk have money to burn.

Any - Coolant changes - Andrew-T

[ deleted ]

Edited by Andrew-T on 14/11/2015 at 17:27

Any - Coolant changes - skidpan

Point by point:

I'm with John F on this, use the same antifreeze for the lifetime of the car and if you need some for top ups what's wrong with getting some from you local scrapyard out of a scrapped car? Plenty good enough.

To repeat what I and others have said antifreeze has a max life. To use it beyond that will risk freezing or corroding your engine.

It's like new tyres, get the cheapest Chinese rubbish you can find or of course go to your local scrapyard, plenty of choice there.

Cheap Chinese tyres may be black and hold air but they tend to be poor in the wet and some are difficult or even impossible to balance. Scrapyard tyres could be off a car that has been in a serious accident. Do you honestly wish to compromise the safety of yourself and others.

Oil, go to Wilcos and buy some 20W/50 for £2 a gallon, none of this expensive synthetic stuff for us clever savers. Or try the local etc......

20w50 might have been OK in the 60's but now manufacturers have a specific oil that matches their engines needs. Putting in the wrong stuff is a recipe for disaster.

No wonder there are so many issues on this site that should could have been avoided through propper maintenance.

Water,what's wrong with good old tap. I went for a meal the other night and they tried to sell me some fancy bottled stuff. You must be joking said I, tap water is good enough for me and put some ice and lemon in while you're at it.

As for water I have been using tap water in engines all my life and not had a problem. But I don't use it strait from the tap, I leave it for a few days to allow all the trapped air out, trapped air that creates air locks in the engine and causes many issues.

And the tap water is drained every 2 years when I renew the antifreeze.

As for the cost of all this, changing the antifreeze, using the correct oil grade/spec (don't use expensive brand names - always look for offers - ASDA in at the moement), avoiding cheap ditchfinder tyres amounts to probably an extra £40 a year to my annual motoring costs - a fill up at ASDA or Tesco and my car is properly maintained and safe.

Edited by skidpan on 15/11/2015 at 08:57

Any - Coolant changes - gordonbennet

and some fell on stony ground

Any - Coolant changes - quizman

Thank you Skidpan, my post was tongue in cheek in responce to John F continuing to wind us all up with his money saving tips!

I always use top brand tyres, I use Castol Edge 5W/30 oil and I use already diluted antifreeze in all my engines.

PS for John, why buy expensive Claret when you can go to Lidl and get some really nice red plonk?

PPS for Skidpan, I like Fleurie and for a treat Oregon Pinot Noir, but keep it quiet!

Any - Coolant changes - Andrew-T

Thank you Skidpan, my post was tongue in cheek in response to John F continuing to wind us all up with his money saving tips!

... even I had worked that out ......

Any - Coolant changes - skidpan

my post was tongue in cheek

Got me there. Thought John F had got a mate. Thank god he's still in a club of one.