[Jeroen]

Originally Posted by hserus

If you just switched off your engine and parked it at the service center and he says the level in the expansion tank is a bit low, the remaining coolant is probably inside the radiator?

Yes, Most of the fluid is actually in the radiator and the engine itself. The expansion tank is just that. Nowadays, virtually all car engine cooling system are essentially closed off. The expansion tank caters for the change in volume of the cooling fluid due to higher temperature. On most cars/engines you tend to fill the system via the expansion tank, although many radiators might have a filler cap as well.

So it is normal for the expansion tank level to fluctuate a bit due to temperature differences. But irrespective it should always remain the min / max level. Check what the level is after leaving the car overnight. I always take note of the “cooled down engine level”. It’s easy to check, because it should never fall lower than your first reading! If so, there is a leak.

Jeroen

[akshye]

BHPians, I have a query in this regard. I own Wagon-R CNG. Every time I visit Shell pump, they open up the coolant tank (drip good 20ml from lid in the engine bay in process) and say, "coolant is low, it's all just water now." The company service station never mentions coolant replacement on the other hand; during 10k routine service. The current running is at 75k and car's age is ~5years. What should I do? The coolant is Green in color, BTW.

[hserus]

Originally Posted by akshye

BHPians, I have a query in this regard. I own Wagon-R CNG. Every time I visit Shell pump, they open up the coolant tank (drip good 20ml from lid in the engine bay in process) and say, "coolant is low, it's all just water now." The company service station never mentions coolant replacement on the other hand; during 10k routine service. The current running is at 75k and car's age is ~5years. What should I do? The coolant is Green in color, BTW.

Don't allow Shell personnel to "inspect" your oil and coolant levels. This is a common scam. Keep your bonnet firmly closed and tell them to stick to filling Petrol. Change your oil on a fixed schedule unless you notice an oil leak.

[SN88]

Originally Posted by hserus

What does the original manual that came with your car say? More than colour it will specify a particular type or standard of coolant, check for that rather than the SA assuring you only blue coolant is filled because they only stock that these days.

Hi
I need to find the manual and will try to find this info. But you are right, they only have the blue one now and were pushing me to do a coolant flush and change to blue for Inr 3200/-.

I will try checking the manual and get it done if needed.

[PearlJam]

Originally Posted by Jeroen

Getting the ratio in the mix a bit off is not a problem. Too high or too low is a problem as the fluid won’t cool properly either way, has less corrosive prevention working, or actually accelerate corrosion.

A question related to this:

Suppose you notice the coolant level to be low (below the minimum mark) in a remote place (assuming no leaks, just that you forgot to check the level for a long time). Is it ok to top up with mineral free water, and then drive for say 200-300 kms till you can safely fix the coolant/dilution levels at a proper service center? Or, is it risky to drive even a few kms?

[Jeroen]

Originally Posted by PearlJam

A question related to this:

Suppose you notice the coolant level to be low (below the minimum mark) in a remote place (assuming no leaks, just that you forgot to check the level for a long time). Is it ok to top up with mineral free water, and then drive for say 200-300 kms till you can safely fix the coolant/dilution levels at a proper service center? Or, is it risky to drive even a few kms?

Not a problem at all. A medium size car/engine (say 2.0l) usually has a total volume of 4-6 litres or thereabouts. So even if you add half a liter of DM water it really is not a problem. Smaller engines 3-4,5l.

The corrosion is a slow and cumulative process, so a couple of hundred kilometers and or days with a slightly diluted cooling liquid is not going to be a problem at all.

In theory the boiling point, when slightly diluted, comes down a bit as well. But unless it is extremely hot, and your firewalling the throttle, it should not be a problem really.

If you can still see the cooling fluid in the expansion tank, but it is below the minimum you are likely to only have to add a few hundred ml. It also indicates a small leak and it is not problem at all.

If there is no indication of any fluid left in the expansion tank, you do need to check more carefully, because you are likely to have a bigger leak somewhere. Sometimes the leaks don’t appear until the engine is at normal operating temperature.

Even so, it pays to be careful, when you suspect a leak anywhere, keep checking the level in the expansion tank often. Running low on cooling fluid is a sure recipe for major damage to at least the engine head. Always a costly repair. So best stop and check frequently.

Keep a very weary eye on the temperature gauge if you have one, or for the temperature light to come on. If it does, best pull over immediately safely and stop the engine.

You can top up a warm engine if need be. But you need to be very careful opening the expansion tank cap as the system will be pressurised. These caps usually have some sort of twist mechanism, at the first notch they release pressure and only then can you safely remove the cap completely. Keep the engine running whilst topping up is a good practice. Although if there is still fluid left in the expansion tank it is less of an issue. (the idea is that you don’t want a lot of relatively cold fluid going into the radiator or engine as it can cause cold shock.

Jeroen

[mmxylorider]

Originally Posted by PearlJam

A question related to this:

Suppose you notice the coolant level to be low (below the minimum mark) in a remote place (assuming no leaks, just that you forgot to check the level for a long time). Is it ok to top up with mineral free water, and then drive for say 200-300 kms till you can safely fix the coolant/dilution levels at a proper service center? Or, is it risky to drive even a few kms?

As long as you can see coolant in the reservoir tank even at minimum mark, you are ok. The system has enough coolant to keep it primed. Topping at the earliest opportunity is required and 200-300 km is too much. One will find a place selling coolant sooner.

[Annibaddh]

Another outstanding thread! Thanks for explaining this (just learnt that VW uses HOAT 12++ on 2008 makes and later). This forum is a such a delight for people looking to understand their machines better. Since I've recently started getting my cars serviced at FNGs this info will become all the more helpful.

[hserus]

Originally Posted by Annibaddh

Another outstanding thread! Thanks for explaining this (just learnt that VW uses HOAT 12++ on 2008 makes and later). This forum is a such a delight for people looking to understand their machines better. Since I've recently started getting my cars serviced at FNGs this info will become all the more helpful.

VW is very picky on coolants and has a more detailed standard than just that. Some rather expensive coolants by Glysantin seem to be the only third party coolants available that support VW

[Annibaddh]

Originally Posted by hserus

VW is very picky on coolants and has a more detailed standard than just that. Some rather expensive coolants by Glysantin seem to be the only third party coolants available that support VW

Yes I'm discovering this the hard way. The more research I do, the shorter it comes up. Gosh! Any recommendations for coolant for a Vento Tdi 1.6 2012 vintage?

[SS-Traveller]

Glad someone wrote this thread, explaining the intricacies of different types of coolant.

Originally Posted by hserus

VW is very picky on coolants and has a more detailed standard than just that. Some rather expensive coolants by Glysantin seem to be the only third party coolants available that support VW

Originally Posted by Annibaddh

Another outstanding thread! Thanks for explaining this (just learnt that VW uses HOAT 12++ on 2008 makes and later). This forum is a such a delight for people looking to understand their machines better. Since I've recently started getting my cars serviced at FNGs this info will become all the more helpful.

Many years ago, I'd talked about the reason for stringent adherence to coolant specifications for VW (and some other) cars...

Originally Posted by SS-Traveller

Also on display was a cutaway of VW's TDI engine.
...on the inlet manifold side sits the water-cooled intercooler, which has been integrated into the inlet manifold. This of course helps to make the powerplant so much more compact and lightweight, but makes for higher repair costs in case of failures!

In our opinion, the intercooler being water-cooled leaves an Achilles' heel for the engine under Indian service conditions. We are not finicky about coolant quality and change intervals, and owners / drivers / FNGs are known to add plain tap water (usually alkaline / hard water) to top up the radiator. This can corrode the intercooler, leading to coolant / water ingress into the engine, with predictable results.

So, don't use colour as a guide for type of coolant, and don't use tap water to top up.

[hserus]

Originally Posted by Annibaddh

Yes I'm discovering this the hard way. The more research I do, the shorter it comes up. Gosh! Any recommendations for coolant for a Vento Tdi 1.6 2012 vintage?

The Mahindra XUV user manual in Europe / UK recommends a glysantin coolant as an alternative to the OEM coolant if that is not available, and Mahindra OEM coolant is (yes that is no indicator) the same light purple colour as VW coolant.

I rather suspect, but don't hold me to it, that your Vento might be quite happy on the Mahindra OEM coolant.

Safest recommendation for any German is use the OEM coolant.

[Jeroen]

I just came across a related discussion on an American (AlfaRomeo) forum:

It was all about whether Cooling systems should also require a "sacrificial” plug.

These sacrificial plugs or anodes are a well known way of protecting ships (metal) hull against electrical corrosion or electrolysis as it is known. The basic principle is that due to electrolysis the lowest order metal is eaten away. On ships with brass type of propellors that means the hull. So you add sacrificial nodes for what is known as catalytic protection.

In particular on car engines having metal cilinder sleeves into aluminium heads these might offer additional protection. Different kind of metals create electrolysis obviously, especially when submerged in a fluid which might contain water.

I really can’t recall having come across these on Car Engines ever, but apparently they were used in the past.

The consensus was more or less that these days with pretty high tech coolants and sticking to correct maintenance procedures there is no need for these anymore.

Also adding them afterward to a system not specifically designed for it, might do more harm then good.

I have never come across evidence of electrolysis on car engines. I have come across plenty of evidence of electrolysis on ships, from supertankers to small recreational yachts. Obviously sea water makes the whole process faster, but even in fresh water it happens. As long as there is conductivity in the system, electrolysis is likely to happen. Every ship owner, large or small, knows to pay attention to the anodes on the hull regularly, as they eaten away. I have seen it happen in literally just a few months. As soon as the hull anodes are gone, the hull start corroding to the point where hull plates need to be replaced!

Even today you can still buy these anodes for car engines too:

https://www.summitracing.com/parts/f...EaAoMhEALw_wcB

I had not give it much thought, but when we talk about how the properties of a good coolant protect the engine/radiator against corrosion, we also need to add protection against possible corrosion due to electrolysis.

Has anybody come across these sacrificial plugs on a car engine before?

Jeroen

[stallmaster]

Can I safely use Toyota Pink HOAT coolant in place of MGP Green IAT coolant in my old Maruti cars(Omni, Gypsy, Alto) after flushing the entire coolant lines so that nothing gets mixed?

[hserus]

Originally Posted by stallmaster

Can I safely use Toyota Pink HOAT coolant in place of MGP Green IAT coolant in my old Maruti cars(Omni, Gypsy, Alto) after flushing the entire coolant lines so that nothing gets mixed?

Stick to green coolant but get any generic brand

Puroguard, Valvoline, Golden Cruiser are good brands.