By June Adams
Controlling temperatures and pressure is essential if you want your engine and diesel fuel injection system to function at optimum levels. If you’re already using a diesel fuel injection system, you know that when injection pressures reach 30,000 PSI, they create a fine mist of fuel suitable for more efficient burning. However, this system may be compromised when temperatures risk rising too high. When your diesel vehicle is overheating, the main cause may not be apparent.
But then, with the right information, a keen eye, and a visit to your mechanic, you can know your engine issue and get back on the road. Here are the common causes why your diesel engine may be overheating, and what you can do to rectify it.
Issues with your coolant
The most obvious system to check when your engine overheats is your coolant. You can start by checking your coolant level. If the coolant level is too low, this can allow for air bubbles into the air cooling system. When air bubbles are present in the cooling system, it may decrease the coolant flow, leading to temperatures rising and your engine overheating. If you find your coolant levels are low, add more coolant to the engine.
Matching the quality of the new coolant to what’s in the engine is essential. This means that the coolant quality should be the same as the one in the engine, and if the new coolant doesn’t match the coolant in the engine, you should flush the remaining coolant from the cooling system. Two different coolant mixtures may reach different boiling points and may cause overheating problems.
Broken radiator hose
If you’ve fixed the coolant and still experiencing overheating issues with your engine, the other thing you can check is your radiator hose. If the radiator hose breaks or collapses, fluid won’t be able to get to and from the engine properly, which will result in overheating. A mechanic will be able to spot a broken radiator hose and replace it for you.
Faulty sending unit
There are some diesel engines where the temperature sensor works in conjunction with an electronic sending unit. The sending unit then converts temperature readouts into electric impulses, and sends them to the mounted temperature gauge. If the sending unit is faulty, it gives incorrect or missing data to the temperature gauge. If the wire from the engine’s sending unit to the gauge shorts out or frays, it can cause the temperature gauge to stop working correctly.
Sending unit issues can be checked and diagnosed by running a scanning tool or examining the wiring.
Broken cooling fan
The most obvious place you need to check when your diesel engine is overheating is the cooling fan. Ensure that the fan is installed properly. If the fan is loosely placed or not in the right position, the airflow would be entirely or partially restricted.
It’s recommended that you stick with the OEM fan size. The cooling fan’s work sends a specific airflow volume through the radiator to keep it from overheating. If the fan is too small, there won’t be enough air to cool the radiator core. It’s also essential to ensure that the fan is in the right position to deliver air to the radiator. Something as simple as the fan pointing in the wrong angle, let’s say downwards, can be the difference between an operating engine and a $25000 overhaul bill.
The fan shroud is the housing that usually holds the fan blades in place. It’s essential that the fan shroud, and the baffling be the right size and positioned correctly. Aftermarket models that don’t fit correctly will allow vibrations to move up the shroud and eventually destroy the housing. The position and size of the fan shroud should meet the OEM specs.
Check the radiator cap.
If the filler cap in your diesel engine isn’t tightly closed, it can lead to a drop in the internal radiator pressure. If the radiator’s overall pressure is low, it can cause the boiling point of the coolant or water to be less than usual, and it will lead to the system overheating. Something as simple as failing to close the cap can cause your engine to overheat and probably ruin it.
Blocked fuel injectors
Another common cause of diesel engines overheating is a clogged fuel injector. When this occurs, the injector system doesn’t release fuel properly, causing the engine to work extra hard, which leads to overheating. Dirty, blocked, faulty, and leaking fuel injectors can also cause starting issues, increased fuel consumption, and poor idling, so you must check them often for any clogs or leaks.
When you experience all these additional symptoms, it will be easier for you to know if bad fuel injectors are causing your engine to overheat. Ensure that you inform your mechanic if you notice a strong fuel odor or experience engine misfires. This will help them diagnose your problem. If it’s a lousy injector and you need to fix it or get a new one, you can go to Gold Farb, where they sell high-quality diesel fuel injectors.
Inspect your exhaust system.
Blockage from the air coming out of your engine can cause overheating in the cylinders. The first thing you should do is a thorough visual inspection of the exhaust system. This should include the visible and internal elements of the exhaust piping. If you find no blockage in the exhaust piping, the next place to check for restriction is in the muffler. Ensure that you check the airflow exhaust pressure coming from the engine. If the airflow is less than the minimum amount allowed by the OEM, it means there’s a blockage higher in the exhaust system.
Another possible reason for overheating from the exhaust system is that somehow, the hot exhaust gases are being sucked back into the cooling air inlet. Ensure that you inspect the outflow and airflow direction of the exhaust.
Diesel engine overheating should never be ignored. Ensure that you keep an eye on the temperature gauges, and never push your engine beyond the recommended load.