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Warning signs in your car's fluids

Your car is trying to show you something - are you paying attention?

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05/14/2012 06:42 AM

Do your 12v electrical work properly.

If you've ever dabbled in 12v electrics in your car, you've probably come across one of the enemies of electrical systems - the spiteful little piece of metal and plastic known as the scotchlock connector.

These things are marketed as the saviour of wiring for people who like to do their own modifications. The idea is simple. If you want to splice two wires together, and one of them is an existing wire (like a +12v line, you can use one of these connectors. One side snaps over the existing wire, and the new wire goes into the other side. When you crimp the metal piece it pierces the insulation on both wires and makes an electrical connection. Clip the plastic snap closed and you're done, right? Well - for now. But later on, that connection will fail in all manner of creative ways and you'll be left with nothing but trouble which, for the most part, will be very hard to track down. Scotchlock connectors need to burn in hell.
If you're going to do your own electrical work in your car, do it properly. Use bullet connectors or crimp connectors if you're cutting and splicing wiring. They're just as easy to use as scotchlocks but they're a thousand times more reliable. You need to invest in a crimp tool - looks like a pair of pliers with notches in the jaws - because pliers won't crimp the electrical connection properly. But the end result is secure wiring that won't vibrate or pull apart and won't create electrical problems further down the line. Everything from engines that won't start, to flickering lights, to fried engine management computers to non-working instruments. I've seen all these things caused by sketchy wiring from people trying to scotchlock a new radio into their car.

The attraction of Scotchlock connectors is that you don't need to cut the vehicle's original wiring to splice lines together to make a Y-connection. In reality you are cutting the wiring though, because of the metal blade inside the connector. So given that, just cut the wiring and do it properly. Take one end of the cut wiring and the new wire, and crimp them together into one end of the bullet connector, and take the other end of the cut wiring and crimp it into the other connector. Simple - that's a Y-connection. Clip the two connectors together and you're done. For connections that don't need to be taken apart again, you can use an even simpler crimp connector and just stuff two wires in one end and one in the other.

It goes without saying that any work you do on the electrical system is best done with the battery disconnected. Although if you're the type that uses scotchlock connectors, chances are you never figured out to disconnect the battery in the first place.

There's a lot your car can tell you about what's right or wrong with the internal gubbins of your engine and transmission, if you know how to see and understand it.

Your engine oil

New engine oil is golden brown, smells lovely and fresh and is the nectar of love for the moving parts inside your engine. As it ages, it turns black, absorbing combustion byproducts and contaminants. This is all normal. Things that aren't normal, best diagnosed using your oil dipstick:

Thick globs on the dipstick

If you have snot-like globs on your dipstick when you check the oil, it means your engine could be developing sludge. This is a thick, jelly-like substance that can block oilways and lubrication channels.

Metal flakes

Tiny, almost microscopic metal flakes are not unusual in engine oil. But if you can rub the oil between your finger and thumb (wear latex gloves) and feel the metal flakes, something is badly wrong inside the engine. Get it checked sooner rather than later. Although by the time chunks of metal that big are in the oil, it's normally too late.

Grit-like dirt

If you rub the oil between your finger and thumb and discover tiny grit-like particles, it's most likely bits of carbon not being filtered out, meaning your oil filter could be blocked or is overdue for a change.

Milky appearance

This normally indicates the oil is interacting with water. There's only two ways this can happen - a crack in the engine block or a blown head gasket. The other way to check for this is to open the oil filler cap and look inside the cap - it will have a creamy yoghurt-like substance in it.

Oil is consistently low

Something is leaking. If you see oil on the ground under the car (see below) then a gasket is leaking. If you can start the engine on a cold morning and get blue smoke out of the exhaust at startup, it's likely a valve seal that is leaking (oil drips into the engine when its cold and burns off when you start it up). If you get blue smoke when the engine is hot, it's likely a blown piston ring (oil is getting past it and burning in the combustion chamber).

Oil is bubbly and foamy

This normally happens when the bottom of the crank churns the oil in the sump, which is an indicator that you have too much oil in your engine. Bubbles in the oil prevent it from lubricating the moving parts properly.

Your transmission fluid

This only counts if you have an automatic gearbox, obviously. Similar to engine oil, when automatic transmission fluid (ATF) is new, it's translucent and clean - probably red. Things that aren't normal, best diagnosed using your transmission fluid dipstick:

Metal flakes

As with engine oil, if you can rub the ATF between your finger and thumb (wear latex gloves again) and feel metal flakes, your transmission is eating itself.

ATF is black or smells burned

This normally occurs when the clutches in the transmission are slipping. The ATF caught between them is sheared and burns.

ATF is 'hello kitty' pink

An endearing colour for your pre-school daughter, yes. But if your ATF is this colour, it means coolant is somehow mixing with it. The double bad news there is that the coolant itself has a tendency to attack the seals in the transmission so not only do you have to find the leak, you have to change the internal seals too.

ATF is bubbly, foamy, or sticky

Typically an indicator that your transmission has overheated or been over-filled with ATF. This has the same problem as foamy oil - the bubbles prevent lubrication.

The ground under your car, where you park

Picture credit: Roy Botterell/Corbis

This is always a fun project, not least of which because you need to be sure there were no puddles under your car when you parked to start with. But if you have a clean garage floor, driveway, or street parking space, puddles where you park are another indicator that something is amiss.

Thick golden brown or black puddles

Dip your finger in it and sniff it. Does it smell like oil? Then you have a leaking gasket somewhere.

Thick red puddles

Don't dip your finger in this one. Depending on where it is, its one of two things. If it's in the middle of the car about where the windscreen is, then it's almost certainly leaking automatic transmission fluid. If it's inboard of one of the wheels, it's a leaking brake component. In this case there will usually be a line of it running over the wheel rim and tyre too.

Clear water

This will normally be just inside the rear edge of one of the front wheels, and it's almost always condensation from the air conditioning system, or water runoff from the scuttle panel or sunroof drains. These are all normal.

Coloured water

If the water is green or blue, its most likely coolant, meaning a leaking coolant pipe, the gasket around the water pump, the water pump itself or a leaking radiator. The exact location of the puddle might help pinpoint the leak.