While an oil filter makes obvious sense for keeping soot and other contaminants out of your engine’s crankcase, in some instances a filter for a coolant system might be needed as well. In recent years, several aftermarket companies have started offering this type of product as a fix for a common problem on some 6.0L diesel engines.
The initial signs were a string of head-gasket failures, blamed on an insufficient number of head bolts or perhaps the design of the exhaust gas recirculation (EGR) cooler. But the cause became evident upon examining the coolant consistency and a number of faulty heat exchangers (for both the EGR and oil system), along with comparing the difference between oil and coolant temperatures. The coolant had become murky, clogging the heat exchangers, and was not able to do the job intended. And when the coolant was drained and allowed to sit still for a time, a fine silt settled to the bottom.
The source of the problem
According to various diesel technicians contacted for this story, the source of the silt particles is sand from the casting of the 6.0L engine blocks, which can leach out from the metal lining and into coolant passages of the water jacket. As this sediment plugs up the oil cooler, the problem gets compounded. Less coolant flows to the EGR cooler, and the engine runs hot. Then the fluid begins to break due to the high temps, and the thin vanes of the EGR cooler suffer damage as well.
Repairing these coolers doesn’t come cheap. Tim Anderson of T&A Performance says that a rebuild kit runs about $400, and 9 to 12 hours of labor to install – if you catch it in time.
Going from bad to worse, a 260-degree oil temp will peg the coolant temp gauge, Anderson says, and 300 degrees melts just about every plastic part under the hood. At that point, the engine is a total loss and not repairable.
You can avoid this expensive scenario with some simple fixes – install a coolant filter and follow a few other maintenance tips (noted below).
First, though, how long does it take to put in a coolant filter? This type of product is available from several companies, and most take about an hour.
The kit is mounted in-line with the engine coolant hoses and includes a filter head, spin-on filter, mounting bracket, hoses, clamps, fittings and mounting hardware, along with a bypass valve to make changing the filter easier. Some brands of coolant filters have similar components, but with slight variations in quality and layout. They’re all designed to do the same thing: keep your coolant clean and flowing.
The components of this coolant filter system took about an hour to install.
What else can you do to maintain your coolant system and prevent high temps? Anderson says first make sure you’re using the correct type, as diesel coolant has a conditioner that regular automotive green coolant doesn’t. This additive is anticorrosive and improves longevity, but it also prevents cavitation (bubbles that implode, pitting the outside of the cylinder walls and eventually eroding into the combustion chamber).
In addition, replace the filter, along with draining and flushing the coolant system, at the manufacturer’s recommended intervals, if not sooner when operating in extreme temperatures.
Note too that radiator caps on the 6.0L are prone to failure, and a defective cap that’s venting a white, milky fluid can be mistaken for a blown head gasket. Installing gauges to monitor the variance between the oil and coolant temps is a good idea, because a difference of more than 13 degrees might indicate that your heat exchanger is not functioning properly.
Lastly, if you spot sediment in your coolant, shorten your service intervals and flush the system more often. It’s no guarantee that sludge won’t form, but it’s certainly better than not doing anything at all.
The following are a few car maintenance tips on how to install a coolant filter. Please make sure to follow your owner’s service manual recommendations.
Step 1: Drain the coolant into a clean bucket, for refill later (unless it’s the incorrect type for diesels, indicated by the green color).
Step 2: Apply Teflon® thread tape to the hose fittings and secure them to the filter holder.
Step 3: Attach a bracket to the passenger side of the radiator.
Step 4: After lubricating the gasket of the coolant filter, spin it on the filter holder.
Step 5: Secure the holder with the filter to the bracket.
Step 6: Mark the heater hose (that runs parallel to the intake runner) with half-inch tape to indicate how much to cut out.
Step 7: After cutting out the half-inch section, install a T-fitting with the supplied gear clamps.
Step 8: Cut the coolant hose running to the degas bottle about 3 inches from the radiator, and install a three-eighth-inch T-fitting with hose clamps.
Step 9: Route the end of the hose to the filter.
Step 10: Connect the hose from the T-fitting on the heater hose to the other fitting on the filter holder.
Step 11: This shows how the finished install should look. Use zip ties to secure the hoses away from hot metal.