When you find a leak in engine cooling system, you must decide for yourself whether to fix it yourself or turn to professionals. The following sections describe different types of leaks and provide some tips to help you make your decision:
The radiator is leaking. If your radiator is leaking badly, take it to a trusted radiator store. If they say it's cheaper to replace than fix, do it.
At a radiator shop, ask a radiator specialist what they plan to do and ask for a written estimate. They used to do job. If estimate seems high, call another radiator shop, tell them what needs to be done and ask for an estimate.
Leaks in cylinder block core plugs. Some cylinder blocks have small circular indentations on sides called core plugs or freeze plugs. If you see leaks or signs of rust in core plugs on engine block, or signs that their leaks have dried up and you've been losing fluid lately, you may need to replace core plugs. It is best to seek professional help in this matter.
Check plugs on both sides of cylinder block.
Internal leaks. Sometimes a leak under cylinder head can be caused by an incorrectly installed cylinder head gasket or by too loose or too tight engine head bolts. If you try to tighten these bolts yourself, you could damage washers if you don't have a torque wrench. It is best to seek professional help here. If mechanic only needs to tighten bolts, then cost should be minimal, and replacing cylinder head gasket is much more expensive.
The cylinder head gasket is located between cylinder head and cylinder block.
With modern aluminum cylinder heads, there is a good chance that there may be small cracks in cylinder head that allow coolant to seep in. In this case, when you check wick, you will usually notice heavy smoke from exhaust and/or engine oil and/or engine oil that looks like a mocha. Also, automatic transmission vehicles have a transmission cooler inside radiator that can leak. When coolant leaks, it mixes with pumped liquid, making transfer fluid look like a strawberry milkshake on suction cup. Both of these issues require professional help.
Leaking water pumps. Typically, a water pump that is about to fail will give a loud warning tone and then start leaking before completely failing. On some overhead cam engines, water pump is located behind timing cover and is driven by timing belt, making inspection difficult. Leave it to professionals. If water pump on your vehicle is visible, you may want to check water pump for leaks or signs of rust around it or seals around it.
If pump is leaking at front and spins with belt, pump may need to be replaced. If leak is around gasket between water pump and engine, you can stop leak by tightening bolts holding water pump up. If tightening bolts doesn't help, then you probably need a new pump.
Pressure Leak Detection - Check Cooling System: If you can't find source of leak and your car is regularly losing fluid from cooling system, take it to a service station. accompanying stress test of your cooling system. Testing requires very little time or labor, so a friendly technician can test for free. While you're at it, have a technician check pressure at radiator cap.