Tech Tip: Cooling System Service

Tech Tip: Cooling System Service

So why does the coolant turn to orange sludge in some vehicles? The problem has been blamed on a combination of factors including low coolant level due to a faulty radiator cap or lack of maintenance, oxygen in the cooling system, using water contaminated with minerals or salts, and adding non-approved coolants to the vehicle.

So why does the coolant turn to orange sludge in some vehicles? The problem has been blamed on a combination of factors including low coolant level due to a faulty radiator cap or lack of maintenance, oxygen in the cooling system, using water contaminated with minerals or salts, and adding non-approved coolants to the vehicle.

To avoid sludge problems, the cooling system must be kept full. Close attention also needs to be paid to the radiator cap. A cap that does not seal properly or is contaminated with rust or dirt can allow coolant loss and air to enter the system. The cap should be pressure-tested and replaced if it fails to hold pressure. If contamination forms inside the cooling system, the debris tends to gum up the pressure relief valve in the drop-center style caps. This may prevent the valve from properly sealing, allowing a loss of pressure in the system, coolant loss and additional air contamination that only accelerates corrosion.

Nissan has issued a radiator cap-related service bulletin for its 1999 and later vehicles. TSB #NTB04-018 says overheating and coolant loss problems can be caused by a radiator cap that does not seal properly. The bulletin advises technicians to inspect the gasket on the underside of the cap to see if the gasket is swollen (enlarged) as this can prevent the cap from sealing properly.

BMW issued a recall (#98V178000 in August 1998) covering a radiator cap issue on 1995 5 series BMWs. The OEM radiator cap apparently holds too much pressure and may cause the heater core to burst if the engine overheats. The fix here was to replace the original cap with one that vents at a lower pressure to reduce the risk of passengers being burned by hot coolant blowing out of a ruptured heater core.

Wrong Coolant Mix
In some instances, coolant sludge can occur if the coolant contains too much antifreeze and not enough water, or there is not enough antifreeze in the coolant and corrosion takes over. The recommended coolant mix is almost always 50/50. But if the radiator is drained and refilled without flushing the system, mixing new coolant with old may result in coolant that is too diluted or over-concentrated. Over-diluted coolant (too much water) may prevent the chemical inhibitors from stopping rust, allowing metal surfaces to corrode.

You May Also Like

asTech Expands Remote OEM Solutions to Include Tesla

asTech’s diagnostic devices now offer authentic remote OEM scans on Tesla vehicles.

asTech, a Repairify company involved in remote diagnostics, calibrations, programming and automotive intelligence for the collision and mechanical repair industries, announced an expansion of its remote OEM solutions to now include remote OEM scanning support for Tesla vehicles.

asTech said its diagnostic devices are now able to complete authentic remote OEM scans for virtually every Tesla vehicle (over 99% coverage). The company said this update continues to demonstrate the power and adaptability of asTech’s technology, as well as its dedication to ensuring customers are ready for the future of collision repair.

Kia EV Models Set All-Time October Sales Record

Kia’s EV6 sets an all-time October sales record.

Bar’s Leaks Tech Tips for Driving in a Winter Wonderland

Proper cooling system preparation helps prevent customers from getting stranded.

Toyota Adopts Tesla Charging Standard for Future EVs

Toyota will adopt the North American Charging Standard on its battery electric vehicles beginning in 2025.

ALI Celebrates 10 Years of ALI Lift Inspector Certification Program

ALI Certified Lift Inspectors have inspected more than 1.3 million car lifts.

Other Posts

Milwaukee’s Next Gen M18 FUEL 1/2″ High Torque Impact Wrenches

The M18 FUEL ½” High Torque Impact Wrenches are fully compatible with the entire M18 line.

Philips Xperion 6000 UV Pillar Earns Best New Tool Award

Recognized at Import Vehicle Community’s Import Product and Marketing Awards.

Rivian Launches Apprenticeship Program for Georgia Plant

The program will recruit an initial group to support future industrial maintenance needs through a 24-month training period.

Identifying The Correct Alternator Pulley

Replace the OAD and tensioner with the belt as part of a mileage-based service. Sponsored by Litens.