If you’re constantly topping off your coolant and can’t find any trace of an exterior leak, you may have a blown head gasket. Head gaskets can fail in many ways. First, the gasket can allow coolant to enter the crankcase. The coolant turns your oil milky-white like a milk shake and that destroys your entire engine. To check for that kind of leak, just pull the oil dipstick and examine the oil. If it looks like a milk-shake, you’ve found the problem. The second way they can leak is to allow oil to enter the cooling system. That happens because oil pressure is higher than cooling system pressure, so the oil forces its way into the coolant. To check that, yank the cap off your radiator or coolant reservoir bottle and look for an oily film floating on the top. The third way head gaskets can leak is to allow coolant into the combustion chamber where it’s burned. That’s much harder to diagnose. The coolant simply disappears in the exhaust. On the way out, it damages the oxygen sensors and can destroy the catalytic converter. Some people say you can see white smoke coming from the tail pipe. But that’s not always noticeable. It all depends on how hot the catalytic converter is at the time. The best way to diagnose a heat gasket that’s leaking coolant into the combustion chamber is to conduct a compression test and a cylinder leakdown test. You can also perform a combustion gas test.
Once you’ve determined that the head gasket is leaking, you’ve got a few choices. Replacing the gasket is going to be expensive (at least $1,000). So you may be tempted to try one of the liquid head gasket leak stoppers on the market. Well, ok, let’s talk about those.
You should know that if you want to got that route, you can
immediately forgot about using the cheap sealers (anything costing less than $35). All those sealers are incompatible with coolant. So you first have to drain the entire (and I do mean the entire) cooling system. That means radiator, heater core, and block (pulling the block plugs). Then you pour in the stuff and run the engine for the specified time. After that you have to drain the system again and leave it open to the air for 24-hours. Then you can refill with coolant. These sealers work less than 50% of the time. They’re a lot of work for such a lousy payback.
Instead I recommend Bars Leaks HG1 or CRC’s KW FiberLock sealer. These products pack a 1-2 punch. First, they contain a plug sealant that forms a “finger in the dyke” patch. Next, the temperature sensitive fibers attach to the plug material and melt to form a permanent seal. If your engine is a candidate, these products work 80-90% of the time. Just pour them directly into the radiator (not into the coolant reservoir). You may have to disconnect the upper radiator hose and siphon out some coolant to do this.
Now let’s talk about which engines are good candidates. First off, if you’ve overheated your engine and warped the head, you’re deluding yourself into thinking that a leak stopper will fix that. With a gap in the head and expansion and contraction during normal heating and cooling cycles, no sealer patch is going to stick. Of course, you’ve got very little to lose by trying either of these products. But realize up front that you’re most likely going to end up paying for a head machining and a new gasket. Now let’s talk about the real candidates. If your engine will run for at least 20 minutes without overheating or losing most of its coolant, these products are for you. In other words, you’ll be in the 80% range.
How about the more expensive head gasket sealers—the ones that cost almost $100? Well, how do you feel about being taken to the cleaners? Scammed? Played for a sucker? Get my point. You don’t need to spend that kind of money on a head gasket sealer. If a sealer will work, these two products will do the job just fine.
If the sealer stops the leak, you’re done. You do not have to add additional sealer down the road when you change coolant.
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© 2012 Rick MuscoplatPosted on by Rick Muscoplat