How to Fix Automotive Radiators
Fixing the radiator in your vehicle yourself can be relatively simple and painless, especially if you have an idea of what is wrong with it. For instance, the steps for unclogging a radiator are completely different from the process of repairing a cracked radiator. The first objective, however, is to make sure it is indeed the radiator that has problems, and not a hose, the thermostat or the engine itself.
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Things You'll Need
- If Clogged:
- Radiator flush
- Coolant
- Screwdriver (for the radiator hose)
- If Cracked:
- Epoxy
- Sandpaper
Instructions
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If Clogged
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1
Purchase a radiator flush in a bottle from the local auto parts store. These will usually run about $10 and act like a drain opener in most instances. Going with a popular brand name instead of generic is usually a good idea, too. Generally, the more you pay for the radiator flush, the better it will operate, so do not skimp.
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2
Allow the car to cool, remove the radiator or pressure bottle cap and pour the contents of the flush into it. Make sure the cooling system is full, and replace the cap. Start the vehicle and allow the engine to run for 10 to 30 minutes, depending on the instructions on the back of the flush bottle (different companies call for different times). Turn off the engine, and allow it to cool for at least 30 minutes.
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3
Drain the cooling system completely. To do this, remove the bottom radiator hose and start the engine with a plastic tub or pan under the radiator. This will force the water from the cooling system and into the tub. Be careful not to let any spill onto the ground because coolant is considered a hazardous material and you may be fined.
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4
Reattach the radiator hose and fill the system back up with the manufacturer's recommended mix of water and coolant. Do not replace the cap yet. Start the engine and allow it to run until the thermostat opens. Watch for the water to flow inside the radiator or pressure bottle. If it begins moving, the radiator is no longer clogged. If it just sits there, it could either be time to replace the thermostat or the radiator.
If Cracked
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5
Purchase a metal-repair compound, such as JB Weld or QwikSteel, at the auto parts store. These epoxies are not expensive and do a good job at fixing cracked radiators. JB Weld is a two-part epoxy that comes in separate tubes and requires mixing. QwikSteel is also a two-part epoxy, but it comes in a single tube in a putty form. Break a chunk off and knead it until the inner and outer materials are thoroughly mixed and the putty is one uniform color--a dark gray.
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6
Prepare the cracked area of the radiator by removing any paint with sandpaper, which will allow the epoxy to bond better with the metal. If the crack is actively weeping fluids, drain the radiator until the coolant is below the crack and dry the area well.
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7
Apply the epoxy to the entire cracked portion and the immediate surrounding area, as per the directions on the packaging. Allow the epoxy to dry for at least 12 hours to ensure it cures fully. There is no need to goop epoxy on, or to put half the contents on the crack. Apply enough to cover the crack and about a 1/4-inch around it.
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8
Fill the system with coolant, start the engine and observe the cracked area once the epoxy has cured. If it is still leaking, it could be permanently damaged and professional help or radiator replacement may be necessary. If the epoxy completely fixed the leak, then there is no more to do.
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1
Tips & Warnings
Always wear safety glasses when dealing with coolant.
Never work on a hot engine. Allow to cool for 30 minutes before any radiator work is done.
