Engine de-carbonization has become a mainstay in the automotive aftermarket to keep diesel-powered and gasoline direct-injection vehicles running at maximum efficiency. Rick’s Automotive, Springfield, Mo., services fleets of ambulances from 20 counties throughout southwest Missouri, northern Arkansas and eastern Oklahoma. Engine de-carbonization is included as part of the shop’s 60,000-mile preventive maintenance schedule on diesel engines in these emergency-vehicle fleets, and many other fleets that it services.

Recently the shop tried a new engine-cleaning product that was introduced to them by Bartec USA, a company known for its tire-pressure monitoring diagnostic and service equipment. Called Revive, the product is a water-based, non-toxic and non-flammable fluid and was originally developed for the cleaning and maintenance of aviation jet engines, power-station turbines and large marine diesel engines. Dennis Flanery, Bartec national sales, manager central, said Bartec recently bought the Revive product line from a manufacturer in England.

Rick’s Automotive ASE Master Technician Dan Williams was assigned the task of using the new product on a 2010 Ford Power Stroke. He explained that engine carbon build-up is common on these ambulances because their daily duties, in essence, are much like those of taxis and law-enforcement patrol cars – they sit idling for extensive periods of time and often are driven in everyday traffic. Putting the “pedal to the metal” does not occur as often as some may believe.

Let’s take a look at how the procedure is performed:

1. This 2010 Ford E-350 with the 6.0-liter Power Stroke diesel engine has been well maintained. It has more than 360,000 miles on the odometer but Williams said that it is on its second engine. The replacement engine now has about 125,000 miles on it.

2. Here is a look at the turbine housing veins of the turbo.

3. In order to see how well the product works, Williams wants to examine the EGR valve, the air-diverter enhancement flap and intake air-temperature sensor #2, which is designed to validate EGR flow and function. As many technicians know, the engine compartment is very cramped.

4. First, the intake elbow is removed to gain access to the EGR valve.

5. This is considered to be normal carbon build up on the air-diverter flow-enhancement flap. The carbon is built up on the top and bottom of the flap.

6. The carbon build up on the EGR after 60,000 miles is considered “normal” as well.

7. Although intake air-temperature sensor #2 will be replaced as part of the maintenance schedule, you can see that carbon and moisture have bled through the terminals to the connector.

8. The engine-cleaning procedure is a three-step process that starts with a cold engine. Note that the kit includes three bottles of water-based, non-toxic cleaning liquid and an applicator-spraying nozzle.

9. The first step is to run the engine at 0.45 times the manufacturer’s maximum rpm (redline) of the engine. For the 6.0-liter diesel, Williams determined that to be 1,485 rpm. He used a pedal prop to maintain the specified engine rpm.

10. The application pressure nozzle is pumped up and works best with the bottle upside down. Make note that Revive must be sprayed downstream of the air filter and the mass airflow sensor.

11. The nozzle and pressure pump provide an even flow of cleaner.

12. In the second step the engine should be running at 0.3 times the manufacturer’s maximum rpm, which is 990 rpm for this engine.

13. Using the second bottle, continue the same spraying process. Look at the plume of white smoke exiting the tailpipe. After emptying the bottle, stop the engine and wait 15 minutes.

14. Restart the engine with the engine speed at 0.4 times the manufacturer’s rpm (which is 1,320 rpm for this engine). Spray the last bottle of fluid into the intake. Leave the engine running a few more minutes.

15. The vehicle was then driven for about 20 minutes under varying speeds and loads with the overdrive off the first 10 minutes. Williams noticed another large fume of white smoke exit the tailpipe as he left the parking lot. The drive included city streets and interstate.

16. Components were removed after the 20-minute drive. As you can see, the top of the air-diverter flap is clean.

17. The bottom side, which did not have direct contact with the Revive spray, had turned from hardened carbon to a “gooey” substance that could be easily wiped off.

18. The carbon on the EGR also had been softened.

19. It was first wiped with a shop towel to remove softened carbon build-up.

20 . Then the remainder was sprayed with an aerosol cleaner and wiped clean. Bartec’s Flanery said the softening of the carbon deposits take place during the first step, with the actual cleaning taking place in steps two and three. Cleaning of the exhaust side of the turbo continues for a period of time as the vehicle is driven.

Williams noted that Revive did a better job of softening the carbon deposits compared to other cleaning systems he has used. He added that he preferred the Revive because the water-based cleaner was not caustic and he did not have to worry about skin damage to his hands. He also said that that the white plumes of smoke that blew out the tailpipe during the cleaning process, which took place in the parking lot, were not as offensive smelling as other products he had used. The pump and applicator combination, which was included, was a “nice touch” since an added-cost specialized pump was not required.

Last Chance Before Replacing a Turbo

Dennis Flanery, national sales, manager central, for Bartec, said that Revive is designed to be used as a preventive-maintenance procedure. However, the product has been found to be a “last-chance solution” before a shop is forced to buy a new turbocharger for an engine.

Such was the case a few months ago when he visited a school district in Alabama that owned a fleet of Freightliner school buses with Cummins engines. One bus was five or six years old but was only driven daily for very short trips to pick up students for school and then take them back home.

With only 63,000 miles on the odometer, the truck’s variable geometric turbo impeller was caked with hardened carbon deposits. Flanery said other cleaning products were used to no avail, and with the warranty out of date, Cummins advised the school that the only “fix” was to replace the turbocharger with parts and labor reaching about $3,000.

The first step of the three-step process using Revive helps soften the hardened carbon with the following second and third steps providing the actual cleaning, he said. “With this particular bus, we used one kit to clean the hardened carbon from the impeller,” Flanery said. “So the problem was solved for about one-tenth of the cost of a new turbocharger.”

In Florida, Flanery assisted with the turbo cleaning on a Chevrolet Duramax that was used only inside a U.S. Naval base where the legal speed limit was only 25 mph – the perfect recipe for extreme carbon build up.

“It took two kits to soften the carbon and clean the turbo system,” he said. “We can’t guarantee that this will work every time when a turbo has this much damage, but it is sure worth a shot for any fleet operator who wants to try and prevent unnecessary expenses.”

Flanery advised that after any cleaning, the diesel particulate filter (DPF) may go into the active regeneration mode earlier than normal to help burn up any of the extra carbon soot deposits held in the filter from the cleaning.