91 legacy oil leak

[suubnoob]

Hey folks, Ive got a leak and know veeerrrrry little about cars. Im wondering if someone can explain to me like Im five whats the step by step to determine where it's coming from and how to fix it? Im hoping it's a gasket or something easy thats just worn out and needs to be replaced, but Im pretty ignorant here (like I dont know what the names of of parts I should check... really, explain like Im five. A dumb five year old). Where to start??

Edited June 1, 2012 by suubnoob

[JPX]

Hello and welcome.

 

These are the possible leaking fluids:

1. Engine oil - usually black/brown and unless changed recently, will smell a little like gasoline.

2. Transmission fluid (automatic trans). Red fluid or light brown to brown. Lighter texture and with a mild sweet smell.

3. Gear oil - pungent dark brown or dark yellow. It stinks. And it is very heavy - washing your hands of it will be difficult.

4. Coolant - lots of colors, but usually a greenish/yellow or even a pink color. If it is old or contaminated, it will be brown. It feels watery - glycerin feel to it.

 

Engine oil sources.

Do you have a leak at the front of the motor? Most likely a front oil seal.

 

Rear of engine - dripping on the exhaust manifolds? Most likely a rear main seal. This cannot be changed without removing engine or transmission.

 

Also shown in the picture above - the engine oil drain plug. There is a crush washer that needs to be replaced at each change. I've been able to reuse them on engine oil changes, but it never works on transmission drain plugs.....always use a new one. It is possible some shops crank TOO HARD on the plug and crack or strip the threads of the oil pan - this cannot easily be resolved without a new oil pan or at least repairing the threads.

 

Cylinder head valve covers. Sometimes these can leak. The gaskets can be changed in the car if absolutely needed - although much easier out of the car. There are 2 - one each side of the engine.

Transmission fluid leaks

- Drain plug and drain plug gasket

- Pan gasket (look for the flat pan with LOTS of bolts holding it to the bottom of the transmission.

- Front or rear seals - will leak fluid from a bad seal. Front cannot be changed without pulling engine or transmission. Rear seal requires taking out the driveshaft.

- Cooling hoses at the radiator right in front of the battery. The trans fluid cooler hides out there with the main engine coolant radiator. Small hoses might have loose clamps or bad hoses.

 

Gear oil leaks

At the rear of the car there is a differential case. Sometime the side seals can leak. And more rarely, the fill/drain plugs might be leaking.

 

The front differential might also be leaking. Look at where the axle shafts connect to the housing for any side seal leaks.

 

Coolant leaks - Long list.....

- Radiator - sometimes these crack and leak (easy to change - needs coolant change)

- Radiator upper and lower hose (easy to change - needs coolant change)

- Water pump - not easy to change, usually an indication the water pump bearing is about to blow. Do not ignore this possibility since it could lead to major engine damage (overheating and head gasket blowout)

- various coolant hoses around the intake manifold

- hoses leading through the firewall to the heater core.

- Thermostat housing located under the waterpump

 

Other fluids could include power steering (looks like automatic transmission fluid) and brake fluid (usually runs down the wheels and not under the car per se).

 

If you can figure out where under the car the leak spots are on the ground, it can really help narrow down the possibilities.

 

Hopefully this helps!