How to check for fluid leaks when buying a used car without looking foolish
Checking a used car for hidden leaks at a dealership feels intimidating when you lack mechanical knowledge and worry about awkward interactions with salespeople. People trying to inspect vehicles end up stressing over how to position cardboard under the engine or what to say while waiting, making it hard to spot slow leaks before buying a problem.
What people tried
Every workaround mentioned in the threads below. We haven’t tested any of them — and nobody here is claiming they worked.
- 1Bringing cardboard to place under the car to catch potential fluid drops
- 2Scheduling a pre-purchase inspection with an independent mechanic
- 3Visually checking under the engine bay manually
- 4Contacting the dealer
- 5Putting cardboard underneath the car to check for color
- 6Using a transparent container to catch the drip
- 7Pressure testing the cooling system
In their words
Unedited, grouped by where they were said, most upvoted first within each place, each linked to the thread it came from.
“Sorry I’m a really shy person but I was wondering do people actually bring the cardboard with them and put it under the car???? This doesn’t seem realistic to me. So where do I put it when I walk into the dealership 😭.. how do I even leave it under for 10 mins .. what do I say to the sales man when I’m sitting there for 10 mins with this cardboard. What if I put it at the wrong location instead of the engine because I’m not too knowledgeable”source ↗
“No smell but coolant has gone down by half in a month. Don’t think it’s water as it’s got a little slipperiness to it.”source ↗
“Sorry, it’s got a bluish tint. So not colourless. I had the ac on for maybe 2 hours a couple of days ago”source ↗
“I bought the car less than a month ago and for the past two weeks it’s been leaking a liquid at a very slow drip rate. What could it be? Have contacted the dealer but want to know if this is an easy fix or not?”source ↗
Where this came up
People with this problem also raised
- 10Fluid leak right after an oil change or service
- 3How to tell if a coolant leak is a water pump failure
- 3Found damage on a used car after buying it from a dealership
- 5How to figure out where a power steering leak is coming from
- 7Is chunky oil buildup a dealbreaker on a used car?
- 5How do you check automatic transmission fluid correctly?