The answer depends on what kind of engine you’re using.
The American Association of State Highway and Transportation Officials (AASHTO) has issued guidelines for pre-cooling of diesel engines in some areas, but the most common questions remain about how to pre-oil your engines, according to the Journal of Automotive Engineering.
In fact, the APSA is issuing a new set of guidelines for how to properly pre-soak your diesel engine.
The AASHTM recommends that all diesel engines, even those that run on oil, be prepped before each test, or “pre-soaked” as they’re called.
This means that the engine is in a safe state of repair before each engine test.
The engine should have been tested with fuel and the engine should be clean, but no oil is needed.
This will help prevent a leak from occurring if a leak occurs.
If you have a diesel with an O2 sensor, the engine can also be preheated before an engine test, but not before oiling.
This pre-conditioning will help keep the engine operating properly, according the AASHTO.
“Pre-soaking reduces wear and improve the integrity of the engine,” the guidelines state.
Pre-heating engines can also save fuel, according APSA.
“A pre-heated diesel engine will run at a lower fuel pressure, lower RPM, and more efficiently, resulting in less engine damage and emissions than a pre-heat engine,” according to APSA’s guidelines.
In other words, pre-fueling reduces the risk of damage to the engine and will help it last longer.
The APSA says this process also keeps fuel in the tank.
But not all pre-treatment is good news.
A new study published in the journal Fuel Cell Research, for example, found that the pre-treated engines are more prone to engine wear and deterioration, according a press release from the EPA.
The study tested about 5,500 different fuel cell cars from 20 different countries.
It found that engine wear ranged from 6 percent to 23 percent.
This study also found that pre-treating diesel engines was associated with higher emissions, but this was less significant compared to the other emissions variables.
The EPA says it’s not clear why pre-cooking is more harmful to diesel engines than pre-hydrogen.