Keeping a diesel engine in top operating condition is critical to achieving fuel efficiency and delivering power. If you're not sure whether your ride needs to go to a diesel engine repair services station, keep an eye out for these four indications of trouble.

Low RPMs

The entire premise of diesel systems is that a self-perpetuating process of firing will occur when the engine is achieving enough compression. An engine doesn't necessarily quit if it's having a bit of trouble, though. Instead, it may just operate at lower RPMs. This is especially worrisome if you have to get on the throttle and still aren't achieving the RPM levels you'd expect. If RPM levels on the gauges are fluctuating visibly while the engine is running, turn it off and get the vehicle towed to a mechanic.

Be aware that the engine may not be the only culprit. Failing fuel pumps often produce compression problems in diesel engines, too.

Rumbles While Idling

While a little bit of a rumble is characteristic of a diesel engine in action, there's a big difference between a smooth purr and clunk operation. If the rumble sounds irregular, there's a good chance diesel engine repair work is in your vehicle's future. Unpredictable changes in the rumble should be treated with a lot of concern. The same goes for any knocks, bangs, or clunks. In the worst case, you may be dealing with a thrown rod or a cracked cylinder.

Hard or Failed Starts

Getting a diesel engine to start isn't necessarily easy, especially when working with an old one. Hard starts, however, are problematic. In the best scenario, you might be dealing with glow plugs or injectors that need to be replaced. Even a dirty air filter can create trouble. Hard starts may also be indicative of timing problems.

No start can be a sign of anything from minor problems to major diesel engine repair needs. For example, an injector may be so thoroughly cracked that a cylinder never hits the critical point at which ignition occurs.

Oil Issues

Discoloration of the oil is always a concern. In particular, you want to keep an eye out for oil that has a milky appearance, as this is one of the signs that the coolant is leaking into the oil and that the engine's heads or seals may be damaged. If you regularly need to add oil outside the normal change schedule, that may also indicate problems.

For more information, you will want to contact a company such a South Houston Engine.