A friend went out of the country and left me his car to use. Before he left he said the only thing I would have to do is add some water every 3 days or so. Not thinking straight (I was driving him to the airport at 0500), I didn’t think to ask him - do I add water directly to the radiator, or into the coolant reservoir, or both?
Yes, I am car maintenance challenged.
Thanks
If the cooling system were working properly, you’d add a 50% water 50% antifreeze into the reservoir. The only trouble is that if the cooling system is leaking (which this one obviously is), coolant might not exchange between the reservoir and the radiator like it’s supposed to. You had probably better get hold of your friend and ask him specifically what he wants you to do, because this is not a normal maintenance situation.
Honestly, if I were you I wouldn’t drive the thing at all, because if you’re having to add that much coolant, the car is either severely neglected or on its last legs, and you don’t want to get blamed if it decides to die on your watch.
The cooling system is pressurized (well, it’s supposed to be - if it’s leaking that much water maybe it isn’t). If you do add water directly to the radiator, MAKE SURE THAT THE CAR HAS COOLED DOWN FIRST. Otherwise it will spray steam and hot water right onto your hand and arm (and maybe your face if you are leaning over it at the time) giving you some nice burns and a trip to the hospital when you open the radiator cap.
And something is seriously wrong with it if it is leaking that much water.
The normal mix is 50 percent antifreeze 50 percent water. You can buy pure antifreeze and mix it yourself or buy it already 50/50 pre-mixed. If it leaks that much, your friend may have just been adding water with no antifreeze just to save money. Water alone will work, but won’t work as well as antifreeze. It won’t conduct heat away from the engine as well and it will boil off at a lower temperature (and it will freeze at a higher temperature if you are someplace where it is very cold right now).
Do you really need to drive this car? I wouldn’t be surprised if whatever was leaking suddenly gave out completely at any moment.
Also, keep a LOT of spare water in the trunk. This thing may try really hard to leave you stranded somewhere.
Thanks.
The car is on it’s last legs, and was like that when he bought it. He basically uses it only to get to work every day, which is why I’m not driving it much. I already know about not opening the radiator while the engine is hot - I might not know much about cars, but I do know that!
If the reservoir is an overflow jar, where the pressure cap is on the radiator (or engine) and the reservoir is not pressurized, then as mentioned it’s necessary to remove the pressure cap (cold) to reliably check and fill the coolant. If it’s a surge tank that has the pressure cap (still often called radiator cap) on it, then that’s the place to check and fill it.
I’d check it at least daily to be on the safe side, more often if it takes a pint or more to refill each day.
Actually, water transfers heat better than antifreeze. The problems with plain water are rapid corrosion (antifreeze has anticorrosives in it) and the lower boiling/higher freezing temperatures you mentioned.
Back in the day I drove many a ‘junker’ such as this. I can almost guarantee you that your friend has just been topping it off with plain water as it slowly leaks away. If the car is cold look into the plastic radiator reservoir tank or, again as long as it’s cold, the radiator itself. I’ll bet that the liquid will be clear which means it’s plain water (ALL antifreezes are colored).
Just keep a big jug of water in the car, and if it’s already hot where you are try and avoid any slow moving traffic as it’s much more likely to boil over with no breeze moving past the radiator. And don’t drive it farther than you’re willing to walk or get a ride back if it dies. A cellphone of course would go without saying…
Having had to drive a car for a while with a similar problem, I can give one good piece of advice. Don’t depend solely on the coolant temperature gauge.
A reliable method of determining if the coolant level is dangerously low (and also a good way to provide some ancillary cooling) is to turn on the heater. If you’re still getting HOT air out of the vents with the heater on, you at least have some minimal cooling going on. If there is no heat, or very little/intermittent heat, pull over immediately, let the engine cool a bit, and refill the coolant - that’s a sure-fire sign that the coolant level is getting dangerously low.
If you’re going to be driving a car like this at all, it’s a good idea to just leave the heater on all the time, with the windows open, and the climate control set to fresh air intake instead of recycle.
Also, if the radiator fans aren’t ever turning even when the engine is at full temperature, it’s a good idea to turn on the A/C compressor, which should force the fan(s) to turn on as long as they’re operable. This isn’t really necessary (or desirable) when the car is constantly moving, but in stop-and-go traffic, or when the car is fully stopped, the engine will overheat pretty quickly if the fan isn’t turning.
I would top up whichever cap is highest first, most likely the expansion tank, to a little above the max. mark and then check the radiator to see if it is full. If not then you would be best to fill that too.
If you know it is leaking coolant then I would recommend checking the level every time you use the car, and since you’ll have the bonnet up you may as well check the engine oil, transmission fluid if it’s an automatic, brake fluid and power steering fluid (if fitted). Check the oil by pulling the dipstick when the engine is cold, wipe it clean with a rag then reinsert it before removing it again, to be sure of a true reading. The oil should be between the two marks. There may be a third mark or hatched area, which denotes the ideal amount of oil, the lower mark is the point below which you risk engine damage if you attempt to start the car.
Transmission fluid should have another dipstick, often with a cog symbol on, and should be checked with the engine running and gearbox in park. Be careful when reaching into the engine bay, there could be exposed belts, pulleys etc. and the radiator fan may start without warning. Identify the dipstick with the engine off, start the engine and follow the same procedure as for the engine oil.
P/S fluid could have a translucent reservoir with a steering wheel symbol on the cap, and max. & min. marks on the side. If you can’t tell where the level is try wiggling the bottle (it’s generally on soft rubber mounts) if not or its an opaque reservoir, take the cap off and there may be a dipstick attached to the underside, otherwise just visually check there is fluid in there.
Brake fluid will usually be at the drivers side, near the back of the engine bay and may have a (0) type symbol on it, see above.
It might be worth asking your friend if he minds you bunging a can of Radweld or similar in there, it’s almost certainly cheaper and faster than a proper repair and I’ve used it and seen it used to great effect to cure head gasket symptoms and leaky radiator cores. It’s probably best to try to figure out where the water is leaking first as it’s not going to do anything about a perished hose for instance.