Your liquid car
Created | Updated Apr 18, 2013
Automobile Fluids (the stuff you see on the ground where you park)
First, I must post the caveat that you should read your owner's manual. It will often tell you how to check the levels of these fluids, how to top them up, and what with. There are sub-types of each which should not be mixed with each other. There are also safety precautions to be taken when dealing with these fluids, before and after they have run all over your drive way and into the storm sewer or squirted themselves in your eye.
- Gasoline: Straw coloured, very thin consistency, very flammable, even explosive, frequently under 60 psi pressure in many fuel injected vehicles. If you have a gasoline leak DO NOT IGNORE IT! Fix it before driving the car anywhere or even running the engine. Many gasoline leaks are easily fixable by tightening loose clamps or connections.
-Diesel fuel: Similar to gasoline, distinctive smell, not quite as flammable. Similar concerns, but it can be under DANGEROUS pressures.
- Engine oil: Amber coloured when new, Dark brown to black very soon afterwards, consistency thicker than vegetable oil. Will not be under pressure when the engine is not operating. The level of oil in the engine while running is our immediate concern with oil leaks. Slow leaks may seem like something to ignore as long as you watch your oil level. Unfortunately this will come back to bite you in the wallet later as all that leaked oil will, over time, deteriorate rubber components in the engine compartment which are not meant to cope with oil. It causes them to swell up, and then crumble away. Typically this includes radiator hoses, belts, engine mounts and electrical insulation. Most engine oil leaks are inexpensive gaskets and seals that require a fair amount of time to replace. If you can access them, check for blatantly loose bolts holding the valve cover(s) or oil pan on. At the same time, be careful not to overtighten as squishing these gaskets is also a common source of leakage.
- Automatic Transmission fluid: Frequently red coloured, similar in consistency to engine oil. Similar concerns. The first symptom you may notice with a low level is that you have to cause the engine to rev high before getting any motion out of the vehicle. The bottom transmission pan can be checked for loose or missing bolts. Again, be careful not to overtighten.
- Gearbox fluids (Manual transmission/transfer case/differential). Frequently tan coloured and substantially thicker than engine oil, but not always. Again, most leaks are cheap gaskets and seals that require a lot of work to get to.
- Power steering fluid: Also oil based. Can be red, green, straw coloured. Hopefully not dark (if so, have it flushed out and changed).
Similar concerns. Under very high pressures while operating. Will not be under pressure with the engine off. The low pressure hose fittings and clamps can be easily checked for looseness, but most leaks come when the high pressure hose must be replaced. Look at it and decide if it is a job you can tackle. It depends mostly on access to where it is routed. On many older vehicles this was a quick easy job. On many newer cars it is quite difficult. The two other potential culprits are the pump and the gearbox. I would love to tell you that the parts required to seal these are cheap, but that would be ignoring the fact that specialty tools are usually required as well as a lot of time.
- Brake fluid: Straw coloured, consistency between that of water and vegetable oil. If you have an Antilock Braking System, this fluid can be under DANGEROUS pressure even when the vehicle is not in use. This is a special hydraulic oil that is NOT compatible with any other fluid. Incidentally it is not very compatible with skin or your vehicle's nice paint either. Accidentally mixing any of the above mentioned fluids in your brake fluid will cause expensive and dangerous repairs. All the rubber bits in the brake system will swell up then leak. All brake fluid leaks are serious business. You may notice a soft feeling brake pedal and poor stopping. Some brake fluid leaks are catastrophic, when a flexible brake hose near one of the wheels pops while under high pressure during braking. Most leaks are slower and the frequent culprits are the master cylinder in the engine compartment or the slave cylinders at the wheels. Actual removal and replacement of faulty parts is usually a simple task if rust is not a factor. The trick comes in bleeding the air out of the system afterwards. Someone who knows what their doing should be involved in this, as stopping distance can be seriously affected.
- Hydraulic clutch fluid: Some standard/manual transmissions use brake fluid in a hydraulic system to operate the clutch. Similar concerns. I have never heard of one of these systems that didn't use simple brake fluid, but it would be prudent to check your owner's manual before topping up. Never say never...
- Engine coolant/antifreeze: Used to be standard Green (ethylene glycol based), now often red/orange/yellow or other colours (propylene glycol based). Usually mixed half and half with water before being put in the vehicle. Feels slippery. The green stuff tasted sweet (no don't taste it to find out). Under about 15 psi pressure while operating. Not under significant pressure after the engine has cooled to ambient temperature. Do NOT open up the system while hot! The consequences of a leak are an overheated and damaged engine. Usually also a ruined vacation. There are many possible candidates for coolant leaks. Check to see if the leak is coming from a hose clamp you can tighten or perhaps an easily replacable hose.
-Windshield washer fluid. Blue is common in winter. Pink "bugwash" is common in summer. Pink-block-of-ice is also common for people who forget to change over. Freaky purples and other colours are for he-men who live where ambient temperatures can drop below -50 degrees celsius. Or think they do... Water/alcohol based. Under no pressure when not operating the washers. If it is leaking when you are not operating the system, then check for a cracked reservoir (can frequently be sealed with silicone) or cracked or loose hoses, which can often be pushed back on or have the offending piece cut out. Use your imagination for repairing this system. Have fun. See how little you can spend and still get it working.
- Water: Not a joke, really. Your car will drip water during the summer as the air conditioning system opertates and draws moisture out of the air. Don't panic. But... if you're not sure if it is water, just drop by your local garage and ask the mechanic's opinion.
First, I must post the caveat that you should read your owner's manual. It will often tell you how to check the levels of these fluids, how to top them up, and what with. There are sub-types of each which should not be mixed with each other. There are also safety precautions to be taken when dealing with these fluids, before and after they have run all over your drive way and into the storm sewer or squirted themselves in your eye.
- Gasoline: Straw coloured, very thin consistency, very flammable, even explosive, frequently under 60 psi pressure in many fuel injected vehicles. If you have a gasoline leak DO NOT IGNORE IT! Fix it before driving the car anywhere or even running the engine. Many gasoline leaks are easily fixable by tightening loose clamps or connections.
-Diesel fuel: Similar to gasoline, distinctive smell, not quite as flammable. Similar concerns, but it can be under DANGEROUS pressures.
- Engine oil: Amber coloured when new, Dark brown to black very soon afterwards, consistency thicker than vegetable oil. Will not be under pressure when the engine is not operating. The level of oil in the engine while running is our immediate concern with oil leaks. Slow leaks may seem like something to ignore as long as you watch your oil level. Unfortunately this will come back to bite you in the wallet later as all that leaked oil will, over time, deteriorate rubber components in the engine compartment which are not meant to cope with oil. It causes them to swell up, and then crumble away. Typically this includes radiator hoses, belts, engine mounts and electrical insulation. Most engine oil leaks are inexpensive gaskets and seals that require a fair amount of time to replace. If you can access them, check for blatantly loose bolts holding the valve cover(s) or oil pan on. At the same time, be careful not to overtighten as squishing these gaskets is also a common source of leakage.
- Automatic Transmission fluid: Frequently red coloured, similar in consistency to engine oil. Similar concerns. The first symptom you may notice with a low level is that you have to cause the engine to rev high before getting any motion out of the vehicle. The bottom transmission pan can be checked for loose or missing bolts. Again, be careful not to overtighten.
- Gearbox fluids (Manual transmission/transfer case/differential). Frequently tan coloured and substantially thicker than engine oil, but not always. Again, most leaks are cheap gaskets and seals that require a lot of work to get to.
- Power steering fluid: Also oil based. Can be red, green, straw coloured. Hopefully not dark (if so, have it flushed out and changed).
Similar concerns. Under very high pressures while operating. Will not be under pressure with the engine off. The low pressure hose fittings and clamps can be easily checked for looseness, but most leaks come when the high pressure hose must be replaced. Look at it and decide if it is a job you can tackle. It depends mostly on access to where it is routed. On many older vehicles this was a quick easy job. On many newer cars it is quite difficult. The two other potential culprits are the pump and the gearbox. I would love to tell you that the parts required to seal these are cheap, but that would be ignoring the fact that specialty tools are usually required as well as a lot of time.
- Brake fluid: Straw coloured, consistency between that of water and vegetable oil. If you have an Antilock Braking System, this fluid can be under DANGEROUS pressure even when the vehicle is not in use. This is a special hydraulic oil that is NOT compatible with any other fluid. Incidentally it is not very compatible with skin or your vehicle's nice paint either. Accidentally mixing any of the above mentioned fluids in your brake fluid will cause expensive and dangerous repairs. All the rubber bits in the brake system will swell up then leak. All brake fluid leaks are serious business. You may notice a soft feeling brake pedal and poor stopping. Some brake fluid leaks are catastrophic, when a flexible brake hose near one of the wheels pops while under high pressure during braking. Most leaks are slower and the frequent culprits are the master cylinder in the engine compartment or the slave cylinders at the wheels. Actual removal and replacement of faulty parts is usually a simple task if rust is not a factor. The trick comes in bleeding the air out of the system afterwards. Someone who knows what their doing should be involved in this, as stopping distance can be seriously affected.
- Hydraulic clutch fluid: Some standard/manual transmissions use brake fluid in a hydraulic system to operate the clutch. Similar concerns. I have never heard of one of these systems that didn't use simple brake fluid, but it would be prudent to check your owner's manual before topping up. Never say never...
- Engine coolant/antifreeze: Used to be standard Green (ethylene glycol based), now often red/orange/yellow or other colours (propylene glycol based). Usually mixed half and half with water before being put in the vehicle. Feels slippery. The green stuff tasted sweet (no don't taste it to find out). Under about 15 psi pressure while operating. Not under significant pressure after the engine has cooled to ambient temperature. Do NOT open up the system while hot! The consequences of a leak are an overheated and damaged engine. Usually also a ruined vacation. There are many possible candidates for coolant leaks. Check to see if the leak is coming from a hose clamp you can tighten or perhaps an easily replacable hose.
-Windshield washer fluid. Blue is common in winter. Pink "bugwash" is common in summer. Pink-block-of-ice is also common for people who forget to change over. Freaky purples and other colours are for he-men who live where ambient temperatures can drop below -50 degrees celsius. Or think they do... Water/alcohol based. Under no pressure when not operating the washers. If it is leaking when you are not operating the system, then check for a cracked reservoir (can frequently be sealed with silicone) or cracked or loose hoses, which can often be pushed back on or have the offending piece cut out. Use your imagination for repairing this system. Have fun. See how little you can spend and still get it working.
- Water: Not a joke, really. Your car will drip water during the summer as the air conditioning system opertates and draws moisture out of the air. Don't panic. But... if you're not sure if it is water, just drop by your local garage and ask the mechanic's opinion.
