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To perform a 1987 Chevy S10 coolant overhaul, begin by pressure testing the cooling system at 15 PSI to identify leaks. Owners must have a pressure tester, a borescope, and a radiator flush kit to perform the overhaul on a 1980s GM truck. The 1987 Chevy S10 coolant overhaul suits owners of 1980s GM trucks with muddy coolant, while owners of modern vehicles should skip it.
When to use this approach, and when not to
Readers who should perform the 1987 Chevy S10 coolant overhaul
- Owners of 1980s GM trucks should perform the 1987 Chevy S10 coolant overhaul, as these vehicles often suffer from “muddy” coolant and corrosion due to age.
- DIY mechanics performing cooling overhauls should use this method to learn specific techniques for sealing water pump bolts and cleaning engine blocks.
Readers who should skip the 1987 Chevy S10 coolant overhaul
- Modern car owners (post-2010) should skip this overhaul and refer to general cooling system maintenance guides instead.
- Owners only looking to top off fluid should skip this overhaul and check for basic coolant levels and leaks first.
What to do next about the 1987 Chevy S10 coolant overhaul
- Pressure test the cooling system to 15 PSI to locate the specific source of the leak.
- Clean the engine block by circulating 1 liter of lemon juice or lemon dishwasher through the system.
- Mix the coolant using a 50/50 mix of coolant and water to prevent future sludge buildup.
- Seal the water pump bolts by applying sealer to the coolant jackets before installation.
S10 cooling system repair through thorough flushing
S10 cooling system repair begins with a comprehensive diagnostic to determine if the issue is internal or external. A radiator is leaking often occurs at the metal-to-plastic joints, which is a common failure point for older units. Pressure testing the system at 15 PSI allows for the identification of these leaks without needing to start the engine.
Diagnostic steps also include checking for signs that a heater core clogged or the coolant is muddy. A borescope—a camera used to inspect the interior of cylinder holes for leaks—helps confirm if the head gasket is intact. Compression testing should yield a result of roughly 150 psi to verify engine health before proceeding with the overhaul.
Corrosion in the cooling system occurs when the coolant mixture contains too much water and not enough corrosion inhibitors. This imbalance allows mineral deposits and sludge to accumulate on internal metal surfaces. Over time, this “mud” restricts flow and creates the engine block corrosion seen in older vehicles.
Steps for coolant System Flush Procedure
- Remove the thermostat from the housing.
- Remove the belt to prevent coolant contamination.
- Install the flush kit adapter.
- Connect the hose to the bucket.
- Fill the bucket and cycle the fluid until clear water is achieved.
- Drain the radiator and refill.
The deep clean: Flushing the block and heater core
The deep clean requires a radiator flush kit designed for multiple-component flushing to remove internal debris from the entire system at once. Removing the thermostat from the housing is necessary to ensure that the flush fluid can circulate freely through the engine block. A belt should be removed during this process to prevent coolant contamination of the drive components.
Flushing the heater core is equally important because a clogged heater core can prevent cabin heat from reaching the interior. Connecting the flush kit adapter to the hose and cycling fluid until clear water is achieved ensures the internal passages are clear of debris. The process is complete only once the fluid remains clear of the “mud” that characterizes neglected 1980s trucks.
Engine block degreasing using a lemon juice method
Engine block degreasing can be achieved by filling the system with water and adding a whole liter of lemon juice or lemon dishwasher. This acidic solution works by breaking down mineral deposits that standard flushes might miss. Running the engine hot with this mixture allows the chemical to reach every internal surface of the block.
Lemon juice provides a specific chemical advantage for cleaning old engines compared to standard soap. Using this method ensures that the internal passages remain clear of the heavy scale that leads to engine block corrosion.
- Lemon juice
- Used to dissolve mineral deposits and heavy corrosion from the engine block.
- Dish soap
- Meant for grease and surface grime; it will not remove the mineral scale that causes engine block corrosion.
Truck radiator replacement with an all-aluminum unit
Truck radiator replacement involves swapping the old unit for an all-aluminum radiator which provides superior cooling capacity and longevity. The all-aluminum radiator must match the 1987 S10 mounting pattern to ensure a proper fit. Removing the old radiator requires disconnecting the transmission cooler lines, the lower radiator hose, and the heater core hose.
Replacing the water pump is a necessary step if a water pump leaking is detected or if heavy corrosion is visible on the housing. Applying sealer to the bolts that go into the coolant jackets prevents leaks from occurring at the mounting points. A custom gasket may need to be made if the original parts are no longer available for the 1987 model.
Standard advice suggests replacing a leaking radiator to stop coolant loss. However, the source shows that if the coolant is muddy, replacing only the radiator leaves the internal block sludge to immediately clog the new part. A full system flush of the block and heater core is required to ensure the new radiator remains clear.
Final assembly and system refill
Final assembly requires installing the lower and upper fan shrouds to ensure the fan’s cooling effect is directed into the radiator. A new serpentine belt should be installed to ensure the water pump and cooling fan operate correctly. The system should be filled with a 50/50 coolant mix to provide the necessary balance of heat transfer and corrosion protection.
Verification of success involves running the engine and checking for fluid clarity and pressure retention. A successful overhaul is confirmed when the coolant remains clear and no leaks appear at the radiator support or water pump housing. The result is a cooling system that provides reliable protection against overheating for the remainder of the truck’s life.
1A Auto has not confirmed the 1987 Chevy S10 radiator’s price or shipping
- 1A Auto has not announced the specific price of the all-aluminum radiator used in the overhaul.
- 1A Auto has not specified the shipping availability or costs for the 1987 radiator replacement parts.
A DIYer restoring a neglected truck
Suppose Marcus owns a 1988 Chevy S10 with 47,000 miles that has “muddy” fluid in the radiator. Marcus begins the overhaul by pressure testing the system at 15 PSI and finds a leak where the radiator support meets the plastic. He removes the thermostat and runs a flush kit until the water runs clear, then adds 1 liter of lemon juice to the block to dissolve internal corrosion. Finally, Marcus installs a new water pump with sealer on the bolts and a new all-aluminum radiator.
Marcus prevents his new radiator from clogging with old sludge within weeks of installation. If Marcus had skipped the block flush and only replaced the radiator, the old “mud” would have moved into the new unit, causing it to clog and fail prematurely.
Frequently Asked Questions
How do I check my 1987 Chevy S10 for a blown head gasket?
To check for a blown head gasket, perform a compression test where the truck should hit roughly 150 psi. A borescope should also be used to look inside the spark plug holes for any signs of coolant leakage.
How much pressure should I use when pressure testing a radiator?
The radiator should be tested at 15 PSI to identify leaks without starting the engine. This pressure allows for a steady check of the radiator support and other connections.
What is the best way to clean an old engine block of corrosion?
The best way to clean an old engine block is to flush it with water and a whole liter of lemon juice or lemon dishwasher. Running the system hot with this mixture helps to remove mineral deposits from the internal surfaces.
How do I prevent my new water pump from leaking?
To prevent a new water pump from leaking, apply sealer to the bolts before they are installed into the coolant jackets. This ensures a proper seal even in older engines where the mounting surfaces may have some wear.
Is an all-aluminum radiator better than a standard one?
An all-aluminum radiator generally offers better heat dissipation and is lighter than traditional brass or plastic units. It provides superior cooling capacity and longevity for a 1987 Chevy S10.
Details first shown in 47,000 Miles and FULL of Mud?! Our Project 1987 Chevy S10 Coolant Overhaul by 1A Auto: Repair Tips & Secrets Only Mechanics Know.