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MG TD TF 1500 - Coolant efficiency

Hi everybody,

As we increase the ratio of anti freeze in a coolant we get a better protection against icing point. We also get a higher boiling point.

So everything seems better. But as this ratio increases, the efficiency of the heat transfer feature of the liquid decreases.

I live in a region where icing is not so frequent and the car is often in my garage for these cold
periods.

So my concern is much more toward the high summer
temperatures.

Should I choose a high boiling point (High anti-freese ratio) or a good heat transfer (Low antifreeze ratio) ?

Laurent.
LC Laurent31

You also get some corrosion inhibition from antifreeze. In your case a low antifreeze concentration is probably enough.
Dave H
Dave Hill

Stick with what concentration range is in the Driver's Handbook or Workshop Manual.

Too much antifreeze will find small leaks.

You only need the coolant to cover the lowest temperature but do allow for the air being colder if you are driving through it. Keep the car garaged when it is cold could have it colder than if the engine is running and being driven. Plus if it is being driven the rest of the systems are being exercised. Hibernating the car, even if done properly and fully with drains and changes of fluids and tyres protected, etc., ect., it is rarely as good as regular use all year round particularly in a temperate climate like in France, generally.

What is often overlooked with antifreeze or the coolant (mix) is that the non-freezing element outlasts the anti-corrosion (and lubricating?, I am not sure on that) elements so when garages check and say the antifreeze (part) is still good that only covers part of the story. You should regularly change the coolant at its requirement (2 years? for the old style stuff) before it degrades too much and not after.

Most people do not drain the system enough, can take a bit of effort to get the most out, and leave lots of residue old coolant and possibly muck and crud in the system which dilutes the quantity and effect of the new fresh coolant going back into the system.

If you measure how much existing coolant (and hopefully any crud/muck) against the dry fill capacity that will tell you how much existing old coolant (and possibly crud/muck) was residue.

On all fluid changes I always go for a hot drain (with necessary caution) and leave to drain for as long as possible to get as much existing fluid and crud/mck out as possible. On a coolant change only (not including any cleaning or flush/back-flush/flush) I suggest to fully open up as many hose connections as possible and suck or blow out as much standing existing coolant as possible for the reasons stated before.

With as an example with a (modern) midget or MGB I would also suggest removing the engine block drain tap or plug (and clearing out the aperture), draining the heater matrix and fully draining the radiator.

A clean heating/cooling system will help with high summer temperatures, so -
. have the inside and outside of the radiator and heater clean and clear of debris
. (as necessary) seals fitted and in good condition
. cooling fan clean and in good condition
. fan belt in good condition and fit
. water pump fully working and in good condition
. thermostat fully functioning
. (pressure cap and its seals fully operating and in good condition)
. check for leaks and condition of hoses and clips
. (check heater system is good condition and fully working, no leaks).

Uhm, I went off on one there, cleaning cooling/heating systems is one of my pet things.
Nigel Atkins

Laurent, a 50/50 mixture seems to be an optimum combination for old, green, Prestone. Bud
Bud Krueger

I run pure water in the summer with water wetter added for lubrication and rust prevention. Pure water carries more heat than any mixture. Coolant has its use, but it is a tradeoff between heat transfer and raising/lowering the boiling/freezing point of water.

If your cooling system is working properly, you really should not need to raise the boiling point of water.

If I get around 212 F(100 C) I start wondering what is going on.

I guess if you live in areas where the temperatures are high, it may be prudent to increase the boiling point.

I do add antifreeze in the winter just to be on the safe side.

Bruce Cunha

It has allowed me to run well into the oil pressure range after 2 hrs in a July 4th parade. One of Butch's water pumps solved that problem. Bud


Bud Krueger

Thank you all,
I'm gonna try water wetter and water for this summer.

Redline says the water wetter contains anti corrosion additives. Do you know what kind of additive they refer to. Organic or mineral ?

Laurent.
LC Laurent31

Unless they're very different to other oil companies they won't tell you too much. Attached is a pdf of their safety data sheet if you can pick the bones from it.

You can use it with coolant so could use a weak antifreeze mix to your water as a coolant to save any all year round worries (perhaps 20%?, or 33%).

I'm never sure about using tap water as our's is quite 'hard'. Regardless I'd want to flush and change the water, with Water Wetter, every year (or coolant with Water Wetter every two?) to as much a possible keep the crud out of the system and from it settling inside.

I used a competitor water wetter in a 1990s Japanese modern version of the MG Midget that MG could never had made as good, this with standard coolant mix and can't say I noticed any difference but my mate with a 1990s Mazda Eunos reckoned he could in his car.



Nigel Atkins

Never use tap water, except in an emergency. Use distilled water or condensate from say a tumble dryer.
That data sheet is not very helpful. It lists boric acid / borates, but I don't think its indicative of inorganic or OAT inhibitor technology, either could be there. Although the inorganic inhibitor type is occasionally indicated as preferable for our engines, I can't think of a good reason why. I don't think any harm will be caused by either.
Dave H
Dave Hill

Whatever you use a good thorough hot drain of the existing coolant, thoroughly clearing out all drain points, particularly the engine block drain, then radiator (and heater?). Followed by a cleaning agent in the system and drain that and checking drain points again and then full flush, back-flush and final flush with water and follow the system I outlined in my previous post.

This alone could help the system by removing some of the built up crud and muck in the system that reduces the cooling and to as much as possible remove or reduce 'hotspots'.

I think one really good thorough clean of the system and change of coolant could be followed by just regular timely hot thorough drains only and refill with protective coolant (of whatever form of coolant).

If you use just water and WW then I think many road only users notice more the muck in the system as water is clear and uncoloured. In a way this is good as it can encourage more thorough cleans and changes of coolant (of whatever form) than the just a simple cold (partial) drain of coolant at one point only. But I think some might blame the WW (or other) for the muck being exposed and think it's the WW (or other) that has caused this rather than just exposing it.
Nigel Atkins

Thanks Nigel,
Borate = IAT.

Laurent.
LC Laurent31

No problem. Let us know what you decide and how it turns out with use over the coming long hot summer of driving (hopefully).

I think possibly the greater the amount of antifreeze you use in your coolant the less overall effective, or noticeably effective, the WW will have as a lot of what the WW does the antifreeze does too.
Nigel Atkins

Having done some digging around into the subject, the traditional antifreeze corrosion inhibitors are usually silicate or phosphate based (differs between N America and Europe) and may use borates for buffering and an as antimicrobial. The organic acid technology (OAT) uses 2 ethylhexanoic acid or derivatives and may also use borates for buffering (that is to maintain a neutral or slightly alkaline condition). There are also various hybrids between the two types. The main objection to the OAT type is that there can be a negative long term effect on seals, hence the usual recommendation to stick with traditional antifreeze for our cars.
Dave H
Dave Hill

Your head can spin with the subject of coolant especially if you go into all the various specific sorts for modern vehicles (bit like oil specs).

This gives a bit of lead to Europe rather than the usual search engine bias of all things USA.

"Diverse technologies have been developed to protect engines from corrosion. In Europe, problems with hard water minerals forced coolant technologies to be phosphate-free. Calcium and magnesium, minerals found in hard water, react with phosphate inhibitors to form calcium or magnesium phosphate, which typically leads to scale formation on hot engine surfaces. This could lead to loss of heat transfer or corrosion under the scale."

Though we've probably gone passed most of this now as a reminder I like these simple and quick videos I just found to cover the basics (like with servicing, maintenance, repairs and fault diagnostics basics are always essential first and before being able to move on).

Coolants Explained Part 1 - https://www.youtube.com/watch?v=XBYEm1jMD08

Coolants Explained Part 2 - https://www.youtube.com/watch?v=l-a0NF7Cz7E

The attached Penrite PDF gives some plain English explanations and goes on to just a few of the possible variations.
Nigel Atkins

There is no need for extra freeze protection if you don't park the car for long periods in sub-freezing temperatures. While driving, it's irrelevant since the engine keeps itself warm even in very cold temperatures.

You should not need the boiling protection of 50/50 or greater with a TD. The radiator is huge compared to the engine size. If it's overheating or getting hot spots in the engine, then there is likely build-up of scale somewhere in the system or a mechanical issue.

I live in a temperate / Mediterranean climate and run around 25/75 antifreeze to water in my TC. The car runs nice and cool, even on tours through the desert at temperatures over 110F. The antifreeze is only there for corrosion protection.
Steve Simmons

My guesstimate of 20% wasn't far out then, I did wonder if at that dilution the corrosion and lubricating additives would be enough, seems they are, again subject to a good quality antifreeze being used rather than the cheapest at the cheapest store.

At 25% mix, or above, the WW might still help but much of what it does would be covered by the antifreeze.
Nigel Atkins

Anti-freeze stinks, discolors the paint and is gross to handle. I am much happier with Water Wetter. I primarily use it for the anti-corrosion properties.

Jim
J Barry

This thread was discussed between 11/04/2021 and 17/04/2021

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