What’s the Story With Oil Mixing Into Your Coolant?
Oil in your cooling system can cause it to be a darker, browner colour (or this can be rust).
Had a customer in just last week with their Toyota Wish – noticed a sort of milky, brown gunk swirling around in the radiator. Straight away, that’s a signal that your engine oil and coolant are mixing, and that’s one headache you want sorted ASAP. Oil’s meant to lubricate, coolant’s meant to keep things cool, and neither of them like sharing space.
If you’re driving back from Te Awamutu along Kahikatea Drive or just nipping round The Base for groceries and you spot sludge in your radiator, or the engine’s running hotter than usual – that could be oil and coolant mixing. Doesn’t matter if you’re in a late model Honda Jazz or an older European like a Peugeot 308, this issue can hit any car, especially after those brutal temperature swings we get here in the Waikato. Cold foggy mornings, then baking sun in the arvo, all the potholes on River Road or multiple speed bumps in Rototuna – it all adds up.
Why’s It Happen?
Usually, it’s a sign something’s crook under the bonnet. In our Hamilton workshop, most times we see coolant mixing with oil it’s down to:
Blown head gasket – Dead common, especially on older Subarus and some Hyundais or Mazdas. The gasket’s what separates oil and coolant channels. If you’re unlucky and it pops, those fluids mix. And you really don’t want that – engine can end up overheating quick.
Curious about what a blown head gasket looks like? Here’s an easy breakdown on diagnosing it and if you want to know more about getting it sorted in Hamilton, check out our info on head gasket replacement in Hamilton.
Cracked cylinder head – We’ve seen it happen after a commuter’s sat in peak-hour traffic on Ulster Street when the cooling system couldn’t cope. Too much heat can warp or crack the cylinder head, then the oil and coolant find each other.
Leaky oil cooler – Some cars, especially bigger Euros like BMW X3s, or even a few Isuzus, use an oil cooler. If that part fails, suddenly oil’s going one way, coolant the other – next thing you know, they’re coming out together. Not good. More about sorting out a leaky oil cooler here.
What Do You Notice When Oil & Coolant Mix?
Here’s what lots of folks around Hamilton report before booking in:
Overheating – The engine temp climbs fast in city traffic, especially during Hamilton’s muggy summer days. Hate to say it, but even stopping for a pie in Cambridge and sitting for 5 minutes can be enough to tip things over the edge if your car’s got mixed fluids.
Excess smoke from the exhaust – Amount of times we see this on Suzuki Swifts and Toyota Corollas after a head gasket goes… too many. Lots of white or blue smoke out the back is always a worry.
What Should You Do?
If you reckon your oil and coolant are getting too cosy, don’t muck around. Bring your car in to a proper mechanic (ideally, someone you trust!). Driving round Borman Road or even just popping down to Morrinsville can wreck your engine if it gets too hot.
The fix? A professional oil and coolant flush, followed by tracking down and sorting whatever part has failed. Ignore it and it’ll only get more expensive down the road – and no one wants to be stuck waiting for a tow on SH1!
Mixed Coolant & Oil Service in Hamilton
At Grimmer Motors, we do a thorough coolant and oil flush to get your engine back on track. After that, our techs will make sure no more oil and coolant can mix, with reliable diagnostics and quality repairs. We sort these issues on Nissans, Mitsis, Audis, Ford Rangers, even the odd SsangYong or Geely! Doesn’t matter if you drive a wee hatchback or a workhorse ute – we’ve seen it all, and sorted it too.
If you need honest, quick service for your engine or cooling system in Hamilton, just give us a bell. We’ll get you sorted and back to cruising round the Waikato in no time.