Coping with Car-tastrophies: Coolant Leaks

This may be a bit of an overshare, but we’re all friends here so I’ll just rip this little gem of an icebreaker off and cut to the chase.

Now grocery shopping doesn’t do much for me at the best of times. Until it becomes socially acceptable to swill complimentary Vodka Fire Engines and sing karaoke in an inappropriate party dress and selfie-worthy make-up, grocery shopping definitely doesn’t make the top   10 of Kim’s Fun Things to Do in Public list.

So it was somewhat out of the ordinary, and more than a little embarrassing when I arrived at Coles a bit… umm.. hot under the bonnet.

And by a bit, I mean ‘Brad Pitt in Fight Club without a shirt’ hot (shout out to my over 35 sisters who just mentally fist bumped me with appreciation).

I was hoping my fellow carparkers wouldn’t notice anything out of the ordinary and jumped out sporting my best chill Nothing-To-See-Here, -People face (damned right it’s a thing or I’ve legitimately wasted a lot of hours in the mirror).

It may have been my flushed cheeks and rapid breathing, but I’m pretty sure the smoke-like vapour  out from under the hood gave it away.

People were noticing… staring… as if I was the first woman in the free world to have gotten a little hot under the bonnet on the drive to Coles. My four daughters all stared at me, all with differing and mother-guilting spectrum of concern and embarrassment, I felt I couldn’t let them look on as their mother became a smoking, hot spectacle of public judgement, although the mental suggestion towards a scandalous and risque element did mildly distract me. I may or may not have embraced the role by flamboyantly fanning my face and hastily twisting  my hair up into an I’ve-Got-This messy bun.

Unfortunately, my life is not a romance novel, and being sweaty and flustered with mysterious steam pouring out from under my bonnet was far from a fantasy of mine (at least in a G-rated sliver of literature like this one). Not convinced? I drive a minivan. No romantic novel features a minivan laden with 4 kids, 27 odd socks, three abandoned Maccas drinks, a ukelele random bags, unopened bills and the echoes of too many sibling squabbles over seating preferences. Anyone still care to question me? I didn’t think so.

Not bragging but working in the office of Townsville Mobile Mechanic for nearly a year has taught me a thing or two about cars – mainly that I know shamefully little about them. I asked myself ‘What would Sandro do?’ and channelled my inner Mechanic who, as it turns out is quite elusive and prone to outsourcing inquiries of the like and after an awkward moment of tandem shoulder shrugging, suggested that Sandro would suggest we seek proper mechanical advice.

We tossed a few ideas around over the phone. If we’re being honest, Sandro discusses some possible causes and I just mumbled back some terminology to appear engaged in the conversation. The universe has gifted me with a talent for playing the piano, kicking arse in scrabble, and every now and again I can be funny. Understanding the inner workings of a car engine, though, to me is right up there with trying to learn quantum physics by osmosis through a Japanese textbook.  Words like radiator hose, coolant and gasket were prominent as potential suspects. I couldn’t pick a radiator out of a line-up if it was wearing a name tag that said “I’m a radiator” but I’d worked in the office long enough to know it could be an expensive car part to replace. Marvellous. Apparently, it could be as simple as a coolant leak, but being a female for 34 years has taught me to respect if not fear any leaking fluid. White smoke, Sandro. I guess it could be steam. Tremendous. Yes, as a matter of fact the temperature gauge was sort of skyrocketing during the last stretch to Coles. Best not to drive it until diagnosed properly. That’s just splendid. I guess I’ll just trot my entourage through grocery aisles then while I await the verdict, not even begrudging the complete absence of complimentary alcoholic beverages that might potentially boost my morale and lessen my dread towards the fate of my Funbus.

Woo up, Gee!! Now is not the time to judge me for naming my minivan.

My sarcasm was premature. Sheer luck had the Hero’s of the Day in the vicinity, so a diagnosis was close at hand.

Coolant leaks can occur anywhere in the cooling system. Nine out of ten times, coolant leaks are easy to find because the coolant can be seen dripping, spraying, seeping or bubbling from the leaky component. The first symptom of trouble is usually engine overheating. But your car may also have a Low Coolant indicator lamp.

The most common places where coolant may be leaking are:


Water pump — A bad shaft seal will allow coolant to dribble out of the vent hole just under the water pump pulley shaft. If the water pump is a two-piece unit with a backing plate, the gasket between the housing and back cover may be leaking. The gasket or o-ring that seals the pump to the engine front cover on cover-mounted water pumps can also leak coolant. Look for stains, discoloration or liquid coolant on the outside of the water pump or engine.

Radiator — Radiators can develop leaks around upper or loser hose connections as a result of vibration. The seams where the core is mated to the end tanks is another place where leaks frequently develop, especially on aluminium radiators with plastic end tanks. On copper/brass radiators, leaks typically occur where the cooling tubes in the core are connected or soldered to the core headers

Most cooling systems today are designed to operate at 8 to 14 psi. If the radiator can’t hold pressure, your engine will overheat and lose coolant.

Hoses — Cracks, pinholes or splits in a radiator hose or heater hose will leak coolant. A hose leak will usually send a stream of hot coolant spraying out of the hose. A corroded hose connection or a loose or damaged hose clamp may also allow coolant to leak from the end of a hose. Sometimes the leak may only occur once the hose gets hot and the pinhole or crack opens.

Whelsh plugs — These are the casting plugs or expansion plugs in the sides of the engine block and/or cylinder head. The flat steel plugs corroded from the inside out and may develop leaks that are hard to see because of the plug’s location behind the exhaust manifold, engine mount or other engine accessories.

Heater Core — The heater core is located inside the heating ventilation and air conditioning (HVAC) unit under the dash. It is out of sight so you cannot see a leak directly. But if the heater core is leaking (or a hose connection to the heater core is leaking), coolant will be seeping out of the bottom of the HVAC unit and dripping on the floor inside the passenger compartment. Look for stains or wet spots on the bottom of the plastic HVAC case, or on the passenger side floor.

Intake Manifold gasket — The gasket that seals the intake manifold to the cylinder heads may leak and allow coolant to enter the intake port, crankcase or dribble down the outside of the engine.


There are the worst kind of coolant leaks for two reasons. One is that they are impossible to see because they are hidden inside the engine. The other is that internal coolant leaks can be very expensive to repair.

Bad head gasket –Internal coolant leaks are most often due to a bad head gasket. The head gasket may leak coolant into a cylinder, or into the crankcase. Coolant leaks into the crankcase dilute the oil and can damage the bearings in your engine. A head gasket leaking coolant into a cylinder can foul the spark plug and create a lot of white smoke in the exhaust. Adding sealer to the cooling system may plug the leak if it is not too bad, but eventually the head gasket will have to be replaced.

Cracked Head or Block — Internal coolant leaks can also occur if the cylinder head or engine block has a crack in a cooling jacket. A combustion chamber leak in the cylinder head or block will leak coolant into the cylinder.

A coolant leak into the crankcase is also bad news because it can damage the bearings. Coolant leaking into the crankcase will make the oil level on the dipstick appear to be higher than normal. The oil may also appear frothy, muddy or discoloured because of the coolant contamination.

Leaky ATF oil cooler — Internal coolant leakage can also occur in the automatic transmission fluid oil cooler inside the radiator. On most vehicles with automatic transmissions, ATF is routed through an oil cooler inside the radiator. If the tubing leaks, coolant can enter the transmission lines, contaminate the fluid and ruin the transmission. Red or brown drops of oil in the coolant would be a symptom of such a leak. Because the oil cooler is inside the radiator, the radiator must be replaced to eliminate the problem. The transmission fluid should also be changed.

One replacement radiator hose later and the Funbus is back in the road and nestled once again inside my elite circle of trust.

By Kim Hoffensetz


You comment will be published within 24 hours.


  • Martin Lisa
    November 13, 2022, 11:58 am REPLY

    I have faced leaking issue last year when I ran my car for long 400 km. But got an expert garage and he did the same thing you have mentioned here. I think everyone should read this blog to know where ,when, how this leaks occur.

  • Mylah Adair
    May 10, 2023, 8:14 pm REPLY

    My old automobile had a coolant leak problem. I didn’t want to deal with this problem, but eventually I was able to fix it with expert assistance. I appreciate you sharing this useful information.

  • Mylah Adair
    May 10, 2023, 8:14 pm REPLY

    My old automobile had a coolant leak problem. I didn’t want to deal with this problem, but eventually I was able to fix it with expert assistance. I appreciate you sharing this useful information.

  • Mylah Adair
    May 10, 2023, 8:16 pm REPLY

    My old automobile had a coolant leak problem. I didn’t want to deal with this problem, but eventually I was able to fix it with expert assistance. I appreciate you sharing this useful information.

  • Carros Usados
    September 22, 2023, 6:25 am REPLY

    Coolant leaks can be a nightmare for car owners, and this blog post addresses the issue with practical advice on coping with coolant leaks. It’s a helpful resource for those facing this common car problem, offering guidance on troubleshooting and managing the situation effectively.