How to Seal the Small Holes After Removing CNG Conversion?
4 Answers
The safest method is to replace the entire intake manifold. Although this approach involves higher costs, it offers the best results and safety. Alternatively, you can use screws to block the holes in the intake manifold and then reinforce them with sealant.
The holes left after converting from gas to oil must be sealed tightly. I've handled quite a few of these jobs before. Typically, these holes are drilled into the fuel tank or the car body to install gas cylinders or pipelines, and after removal, they need to be sealed with specialized materials. I first clean around the hole to ensure there's no oil residue or rust, then fill it with a high-temperature-resistant sealant, such as automotive epoxy, which can withstand engine heat. If the hole is relatively large or was originally used for bolts, I'd recommend reinforcing it with a rubber plug and glue to prevent future loosening or oil leaks. Preventing leaks is crucial—otherwise, oil and gas seepage can cause odors and may corrode components. I've also seen some cars experience fuel leakage due to poorly sealed holes, so it's best to have a professional mechanic inspect the system's integrity to ensure the repaired holes won't affect driving safety. During regular maintenance, it's also a good idea to check the sealing condition to prevent small issues from becoming major problems.
My car was previously converted from gasoline to CNG, and after removing the device, the small holes left behind really gave me a headache. I searched online and asked a few car-owner friends, and generally, small plastic plugs or rubber caps can do the trick, but you have to choose high-quality ones—don’t just slap on ordinary tape and call it a day. After cleaning off the dust around the holes, gently press the plugs in tightly. However, the holes might be slightly deformed after removing the conversion equipment. I’ve tried it myself, but the results were inconsistent. It’s best to drive to a repair shop and let a mechanic check if additional welding reinforcement is needed. This is a safety issue—if the holes aren’t sealed, fuel vapors can leak from the engine bay, causing odors or even greater risks. I hesitated at first, thinking of saving money by doing it myself, but eventually, I let the shop handle it properly to avoid worrying about the car acting up in the middle of the night. Don’t ignore leftover holes after removal—regularly check the seal to keep your car running with peace of mind.
Plugging the hole after converting from oil to gas was so much fun, I did it myself. Just using some automotive sealant or epoxy is convenient enough, and you can buy matching tool kits online. The steps aren't complicated: clean the hole of dust, apply the adhesive evenly, and wait a few hours for it to dry. I recommend choosing heat-resistant materials to avoid softening from high temperatures while driving. Once, I didn't plug it tight enough and had a small oil leak, but just cleaned it up and repaired it again. The hole left after removing the equipment was mainly for temporary modification drilling. After plugging, check around for any other gaps and deal with them to make the car body more durable. This job isn't scary at all, just prepare gloves and a clean cloth, and you can easily handle it.
