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What causes engine blow-by, and can you fix it without rebuilding the engine?
Most of the time, yes. Blow-by is a serious mechanical problem, and if you let it go long enough it gets much worse. But in the majority of cases the root cause isn't worn rings. It's carbon. Hard carbon deposits that have built up in the compression ring grooves and on the cylinder walls are what's causing the compression ring-to-cylinder wall seal to fail.
And carbon is a fixable problem.
Carbon doesn't dissolve. You can't flush it out with a solvent. What removes it is the same thing that created it: combustion. That's the principle behind FTC Decarbonizer, and it's why the fix doesn't require taking the engine apart.
Two products address the two causes. FTC Decarbonizer is added to the fuel and catalytically enhances the combustion process, oxidizing all hard carbon from the compression rings and cylinder walls. Flushing Oil Concentrate is added to the engine oil and works to clean the oil control ring. The engine remains in operation throughout - no downtime. More on both below.
What's actually happening when an engine has blow-by
Every combustion event produces enormous pressure. That pressure is designed to push against the piston and rotate the crankshaft. Compression rings are what keep it in the combustion chamber.
Each piston has two or more compression rings, cast and machined from high-carbon spring steel, fitted into precisely machined grooves in the piston. They expand outward against the cylinder wall through their own inherent spring tension. During the compression and power strokes, combustion chamber pressure also gets in behind the rings and forces them harder against the cylinder wall to ensure an effective seal.
When the compression seal fails, combustion chamber pressure escapes past the rings into the crankcase, pressurizing it. That's blow-by. The crankcase gets over-pressurized and that pressure vents through the PCV valve and additionally, the engine breather tube on many diesel engines. Extreme blow-by pressure will also force engine oil from critical engine seals and gaskets. The engine loses power it should be putting out.
Signs your engine has a blow-by problem
Blow-by affects both gasoline and diesel engines. It doesn’t usually become apparent with a single obvious symptom. Often it can show up as several things going wrong over time, with each one progressively getting worse.
Smoke-like vapor from crankcase vents.
A direct sign. While the engine is running, remove the oil filler cap and watch for pulsing vapor or pressure from the filler neck. Check the PCV valve pipe for oil vapor or oil residue. On many diesel engines, also look for smoky vapor or oil droplets from the engine breather tube. Pressure pushing oil droplets or mist out of those vents is blow-by.
Oil consumption you can't explain.
When compression rings fail to seal, oil gets past the compression rings into the combustion chamber and burns. Your engine will use more oil than it should, and possibly blue or grey smoke is seen from the exhaust. On gasoline engines, pull a spark plug: oil-fouled tips are often a reliable field indicator. Stab-revving a stationary gasoline engine and watching the exhaust for blue smoke is another quick check. Occasionally, unexplained oil leaks from critical oil seals and gaskets is another indicator.
Low or uneven compression.
A compression test is often a reliable way to confirm compression ring seal failure. Low readings across cylinders, or readings that vary significantly between cylinders, can be a highly likely indicator. Further verifying tests are recommended.
The engine feels flat.
Compression pressure escaping past the rings is pressure that isn't pushing against the piston. Engine power is lost. Fuel economy drops. The engine feels sluggish overall and just doesn't operate the way it used to.
Cold start problems, particularly on diesel engines.
Diesel engines ignite and combust fuel through compression pressure alone — no spark plugs. When the causes of blow-by have reduced the compression pressure, a cold diesel engine may crank longer before finally starting, produce white exhaust smoke as partially combusted fuel vapor on startup, and clear only once the engine reaches operating temperature. Gasoline engines are less affected at cold start because they don't rely on compression for ignition. However, severely low compression can cause hard start conditions.
Why compression rings stop expanding and sealing
Carbon is the culprit in most cases. Here's what it does and why it's such a problem.
Carbon in the ring grooves. Incomplete or inefficient combustion leaves unburned carbon residue behind. That residue accumulates in the grooves that locate the compression rings on the piston. The clearance between groove wall and compression ring is tiny by design. As carbon builds up in that tiny space, it progressively diminishes correct ring expansion and consequent effective sealing. Eventually the hard carbon fills the entire space, becoming a solid, cement-like crust and the ring is rigidly locked in place. It can't expand outward under its inherent spring tension. Compression and combustion pressure can't get in behind it to fortify the ring's outward expansion. Both ring-to-cylinder wall sealing actions are severely compromised. The ring is cemented in the groove, it can no longer seal effectively, and blow-by is the result.
Cylinder glaze. At the same time, carbon builds up in the cross hatch micro-grooves machined into the cylinder wall. Those micro-grooves hold the engine oil that helps compression rings seal effectively. As carbon fills them and is polished smooth, the oil cannot be retained on the cylinder wall and the ring-to-wall sealing effect is degraded. You end up with a glassy, shiny, carbon-polished surface. That's cylinder glaze.
Sludge in the oil control ring. The lower ring on each piston has a completely separate job. It controls the amount of oil on the cylinder wall and scrapes excess oil off and drains it back into the sump through slots in the piston, leaving just enough oil in the cross hatch micro-grooves to help the compression rings seal. When engine sludge blocks those drainage segments and slots, the oil control ring can't do its job. Too much oil stays on the wall, gets past the compression rings into the combustion chamber, burns, and creates more carbon and soot. Those soot particles circulate back into the oil and accelerates sludge buildup.
Diesel engines cop the worst of this. The diesel combustion process typically produces more carbon byproduct, and US diesel fuel quality is generally poor by world standards, exacerbating the carbon byproduct production problem.
How the Engine Blow-by Pack actually fixes it
Blow-by has two causes that need to be addressed separately. FTC Decarbonizer handles the heavily-carboned compression rings and glazed cylinders. Flushing Oil Concentrate handles the blocked oil control rings.
FTC Decarbonizer.
Add it to the fuel tank. As it catalytically enhances the fuel combustion process, it lowers the combustion temperature of carbon deposits, causing them to oxidize and burn off during normal engine operation. In the combustion chamber, FTC Decarbonizer works on the compression rings, in the compression ring grooves, and on the cylinder walls. As deposits burn off the ring grooves, the compression rings recover their ability to expand effectively. Combustion chamber pressure gets in behind them again. Cylinder glaze burns off at the same time, restoring the vital crosshatch micro-grooves.
Flushing Oil Concentrate.
Add it to the engine oil as part of an oil change. Flushing Oil Concentrate is a highly concentrated blend of premium detergents and dispersants that safely and effectively dissolves and suspends the sludge blocking the oil control ring's drainage segments. This action restores the ring's ability to once again correctly control the oil on the cylinder wall. It works below the compression rings — in the oil control ring and throughout the entire lubrication system. The dissolved and suspended sludge drains out with the oil change. FTC Decarbonizer can't do this job. Flushing Oil Concentrate can't do FTC Decarbonizer's job. They address different components with different processes, and both are needed to ensure engine blow-by is dealt with adequately.
The rings free up progressively as the carbon is removed. No disassembly required at any point.
FTC Decarbonizer and Flushing Oil Concentrate are perfect for all gasoline and diesel engines and should be used as part of a regular maintenance routine. If your engine is showing signs of blow-by and the suspected cause is carbon and sludge, the Engine Blow-by Pack will fix it.
Is it worth treating before you rebuild?
A gasoline engine overhaul might cost as much as $7,000. A diesel pickup starts at $15,000 to $20,000. Larger trucks, semi-trailers, and other larger diesel-powered equipment easily run $25,000 to $50,000. Mining and large industrial engines reach $400,000 to $500,000. If the blow-by is suspected to be caused by carbon and sludge, the Engine Blow-by Pack will fix it at a tiny fraction of those costs.
How the Engine Blow-by Pack actually fixes it
Solvent-based fuel system cleaners are widely marketed as a solution for blow-by. They don't work on hardened carbon. Carbon cemented into a compression ring groove doesn't dissolve. A solvent passed through the fuel system simply cannot remove it. The rings stay stuck.
FTC Decarbonizer works because it significantly enhances the entire combustion process. Its catalytic effect lowers the combustion point of the carbon so the deposits oxidize and burn off as part of the combustion cycle. It reaches the ring grooves because the combustion flame reaches the ring grooves. It's active with every combustion event, continuously, for as long as it's in the fuel.
On the oil side, no fuel additive reaches the oil control ring. It sits below the combustion zone. If sludge is blocking the oil control ring's drainage segments, the only fix is a highly concentrated, safe-to-use, specially formulated detergent in the oil that dissolves the sludge directly. That's Flushing Oil Concentrate.
Frequently asked questions about engine blow-by
What people are saying
“I’ve got a 2011 Chev Express van with the 6.6 Duramax. It had been gradually getting lower on power over time and just wasn’t running the way it used to. I put it down to stuck rings and a slow turbo. I ran your FTC Decarbonizer and for a while nothing seemed to change. But around about a thousand miles of using it, it suddenly started to run so much better and had a huge boost in power. I had done nothing else to it except add the FTC Decarbonizer. Now it runs probably as good as it ever did, if not better. I figure it just took a while to burn off all the carbon around the rings and on the turbo. Very happy with the result. It’s much cheaper than an overhaul or a new engine. By the way, I’m a diesel mechanic. A bunch of my customers are now using it and seeing the same results. Thanks for a great product.”
David R, Hillsborough, NJ
Really great result
Amazed at results!
2012 Kenworth W900
No teardown!
Saved an engine overhaul
Kubota problems fixed
Detroit Series 60 revived
Audi A4 oil use
Toyota troubles remedied
Dramatic decrease in oil consumption
Ready to fix the blow-by?
If the cause is carbon and sludge build up, the Engine Blow-by Pack will fix it. This pack contains both FTC Decarbonizer and Flushing Oil Concentrate which work together to remove harmful carbon and sludge deposits during normal engine operation, costs a fraction of a teardown, and is perfect for all gasoline and diesel engines from the smallest to the largest.