BLOWN HEAD GASKET?
i want to do a survey .... if you have blown a head gasket in the past... i want you to think back to what octane fuel you were running at the time.... ware did you buy your gas?

what is your theory on all the blown head gaskets???
not just Ford but ALL MAKES

it is my belief that Today's fuels are to Blame!!

NAME YOUR FUEL .. ... .. LETS GET TO THE BOTTOM OF THIS

 

i'll contribute even though i do not know for certain what caused my headgasket to blow, too many variables, but on my civic i bought it with a blown headgasket from the prev. owner flooding the cylinders when he wired up the injectors wrong, then i re did the h/g and it blew again, but upon closer inspection i do not believe the replacement gasket never sealed??? so i used a headgasket from a 92-2000 civic and it worked for a while, but slowly began consuming mas quantities of oil till i partially spun all four rod bearings when it ran two quarts low while driving (i put 150 hard miles on my car that day, like wrapping out each gear, fifth to third downshifts, hittin the rev limiter, etc). i'm glad i don't beat on my van like that...

to answer your question i used 89 octane gas, usually texaco chevron or shell, but twice i got arco gas, i never noticed the difference besides the cost of the gas...

mind if i ask what you are researching for? i always thought that blown headgaskets came (for the most part) from lack of maintenance. like, the car over heated because i didn't change my water pump and it seized up causing an over heat or i ran strait water and it left massive deposites which ate away at the gasket or i suppose it could be related to excessive combustion temps from running lean or misfiring, which also can come from not maintaining the car ya? just a thought

 

Blown head gaskets are a function of heat. When the coolant level drops below the heads, or the coolant circulates poorly, the heads heat up at a different rate than the block, this causes the heads to warp, and opens up a gap in the head gasket. Once the gasket lets go, it just deteriorates. The fuel has no impact on a head gasket at all. Even extremely high octane race fuel with nitrous boost will not ruin a head gasket unless the head is not adequately cooled.

the big mistakes are:
running low on coolant
using tap water in the cooling system
failed water pumps
failed thermostat
the use of leak-stop products
failure to replace old antifreeze with new on a regular basis
obstructions in the cooling system
obstructions to airflow through the radiator
weak fan

Causes of repeat failures include:
failure to fix the original problem
not resurfacing the old head before installing the new gasket
reusing the original head bolts
the use of leak-stop products

No brand of fuel will have any effect on the gasket because the fuel does not burn hot enough to warp the head. Higher octane fuel will often burn cooler because the octane inhibits premature ignition. Using a low octane fuel can result in higher combustion temps, but only if preignition (pinging) is actually occurring, and even at that, the head is unlikely to be affected, though damage to the piston could occur. There are also no additives that could corrode or otherwise harm the head gasket directly.

 

Detonation will cause head gaskets to blow, and that can be a function of fuel quality. Low quality fuel tends to detonate more under load. This can also be traced back to lack of maintenance, either back off on the ignition timing, or de-carbon the combustion chamber.

 

While detonation causes excessive heat, is the head is properly cooled, the head and gasket should suffer no ill effects because the coolant flowing through will remove the heat. The same cannot be said for the pistons and valve, those are among the first things damaged by detonation.

 

The damaging effects of detonation comes more from the uncontrolled pressure waves that they generate, as well as the localized hot spots. Detonation causes pistons to rattle in the cylinder, which is the source of the "pinging" noise that you sometimes hear. Otherwise, most detonation are supersonic, so yo can't even hear it when it's banging up your engine.

It's the uncontrolled explosions that can blow head gaskets, and have been known to punch holes in the tops of pistons.

 

In most cases, blown headgaskets are simply a function of aging. Sandwiched between cast iron surfaces, gaskets are subjected to thousands of cycles of expansion and contraction, each cycle causing micro-abrasion of the composite gasket surfaces. Eventually, the gasket is eroded past the point contaiment of pressures from combustion or coolants are possible. No matter how well maintained, all headgaskets will eventually fail.

As mentioned, operating an engine low on coolant severely overheats the heads which in turn causes warpage and early gasket failure. Replacing gaskets on a warped head will lead to more early failures.

I've often wondered if the standard carbon removal procedures (water based solvents) hasten demise of the gasket by introducing steam pressures far in excess of normal combustion pressures. I have no hard facts to support this theory, just a hunch.

 

I disagree, no matter how many miles the vehicle has, the head gaskets should hold. I have a Mazda with 515,000 and it has never had a head gasket blow. None of our Aerostars have had head gasket issues, nor has any of our other vehicles. My siters Civic blew a head gasket, but her fan relay and temp send both failed and that resulted in the overheating needed to cause failure.

There is nothing you can put through the engine shy of hydrolocking it that can significantly increase the pressures in the cylinders. The typical pressure in the cylinder during operation is roughly the same as the peak compression you get in a compression test.

If you are going through a lot of head gaskets, I would ask yourself some questions:
If these are a lot of different cars, maybe this is a fuel problem and your theory holds water, but if it is the same car over and over again, look into any of the following:

Is the cooling system performing adequately, i.e. good coolant flow, the coolant is in good condition, the thermostat opens and closes at the proper position and temperature, the fins on the radiator are lear of bent fins and debris, the fan is working properly, the fan clutch is working properly, the fins on the water pump are in good condition, etc.

That a warped head was not reinstalled. If you remove the head for any reason, I recommend having a machine shop resurface it just to be sure. A warped head will prevent the new gasket from seating properly.

New head bolts. The head bolts are a torque to yield type, which means that they are torqued till they stretch a certain amount. This holds the head firmly. But the bolts can only be used once. If they are removed and reinstalled, they do not stretch properly the second time. Use new head bolts every time you remove the head. make sure you use a torque wrench to ensure the proper torque was achieved.

 

While you are welcome to disagree, the fact remains, on a microscopic level, these are mechanical components that move and as such will indeed wear over a period of time. The wear rate is factored in during design to hopefully be less than the expected service life of the engine. Different manufacturers use their own specifications and as such, some head gaskets will last longer or shorter than others.

An interesting article on head gasket technology that does support the microscopic failure mode. Tech Feature: Cylinder Head Gasket Service Essentials - Underhood Service

 

""""There is nothing you can put through the engine shy of hydrolocking it that can significantly increase the pressures in the cylinders. The typical pressure in the cylinder during operation is roughly the same as the peak compression you get in a compression test.""""""

i'll save you the advanced mathematics. Combustion pressure works out to approx. 4 times static compression pressure in a normal run of the mill gasoline fueled car engine.

ether will work just fine to significantly increase the pressures in the cylinders, until something breaks.

http://www.hcs.harvard.edu/~jus/0303/kuo.pdf

it's too easy to cook the heads on our 4.0Ls, especially the early ones. the infamous #5 cyl head gask. leaker, cracked heads around valve seats. the block was stretched to its max displacement and hp. too easy to overheat especially in the cramped poor air flow Aero engine compartment.

good read AeroC on head gaskets.

 

The microscopic theory only holds true for fiberous and stamped steel gaskets though, most good gaskets have the raised steel rims, and these steel rims will not significantly wear on en engine where a cast iron head is used, such as the 4.0L. Now with an aluminum head, the expansion rate of the two materials is very different, so with an aluminum head a blown gasket might be a certainty at some point in time. All I know is me and my dad have put enough miles on enough engine to know whether head gaskets fail by themselves or not. The theory also only holds merit in the event of overheating. And it does not hold merit when both the head and block are the same materials used in conjunction with a good graphite based gasket with reinforced edges and multiple materials.

My previous vehicle has 515,000 miles, head gasket is original. My current Aerostar has 215,000 and is original. My dad has a '96 Ranger 2.3L, 340,000 and all original, '00 Dodge Dakota 320,000, '95 Geo Prism 1.6L 420,000 (recently sold to my sister), '92 Ford Aerostar 3.0L 198,000, '92 E350 5.8L 290,000. None of these have ever blown a head gasket, and the 3.0L Aerostar has overheated mildly a couple times due to blown hoses and 2 failed water pumps (it was poorly maintained before we bought it). With that man miles, I think its safe to say that mileage has nothing to do with head gasket failure. This places the microscopic wear theory as just that, a theory. They make the gaskets out of graphite for a reason you know, if the head and block expand at slightly different rates, they can slide past one another without damage to themselves or the gasket.

In oder to see your microscope wear theory hold water, you have to look at much greater heat differentials so as between the head and exhaust manifold, and at that point the gasket still rarely fails, more often the manifold warps, forming a breach and from there the rest is downhill. Even at this point, internal metal fatigue (which is on a microscopic level) is just as likely as gasket failure.

I noticed in this guy article, he is dealing with an aluminum head, a non-graphite head gasket (stamped multi layered steel to be exact) is being shown. Nissan made the same mistake when they began using multi-layered stamped steel gaskets on the 1.8L Sentra and began having lots of head gasket failures. The problem is that the gasket does not have enough yield, and the head and block materials are too different. The stamped gaskets rely on the spring tension in the steel, but being welded between the head and block and subjected to repeated heating and cooling cycles causes the steel to flatten down, loosing its effectiveness as a seal. Also the steel head gasket would have a different expansion rate from either the block or the head. None of this applies to the Aerostars.

 

I've owned countless old/used vehicles since '76 and never killed a head gasket. I had an intake gasket let go in my Exploder. Lucky I guess.

 

I think almost everyone of these 4 liter v6's using the 1 piece intake manifold gasket have or will develop a leak there. Not bad luck, but bad design.

Almost all the blown head gaskets I've seen have been due to overheating that warped the heads. The glaring exceptions were all Chevrolet Vegas; they liked to blow head gaskets just because.

 

mpgvan is on to something

few states nor the Feds test the octane of retail fuel.
get a couple tanks of 80 octane cheapy gas or gas that incorrectly mixed with octane additives (ie ethanol) during tanker fill and we have a signed death warrant for a 4l.

also diesel (octane 20) contamination will cause the problem of low octane pump gas. more common than we think. occurring in the pipeline distribution system, in tank farm pipes and in fuel tankers.

we know the 4L ohv Ford is a notorious pinger predetonation machine with many examples of failed engines from same.
pinging can loosen head bolts, especially these torqued to yield which can be permanently stretched by overstress.

typical senario
4L carbons up from the nature of the beast, poor bank injection system in early ones, poor combustion chamber design in all.
preignition starts from carbon deposits retaining combustion heat. head bolts loosen allowing head gaskets to fail. head cracks from overpressure preignition shock waves. water leaks into combustion chamber, into oil
engine failure.
first blamed culprit that may be spotted when engine torn down is leaking head gasket.
was that what caused the problem?

all later engines with a spark knock sensor will not have the problem, will run fine with 80 octane, driver might notice a power loss if he is a WOT driver.

 

Ok, that is definitely false. A little research into the refining process and how pipelines work tell you that depending on what part of the country you are in, most fuels, regardless of brand, are the same fuel. Also the gasoline industry is highly regulated, both on a national and a local level. All the pumps in Utah have stickers certifying that they have been inspected for accuracy every year, which shows the people who investigate this kind of stuff are active. Throughout the east, most all the fuel is distributed through long pipelines from the Gulf. When a gas company buys say 87 octane, they don't have to wait till the order flows through the entire pipeline, they can get what they need sooner than that because all the fuel that enters the pipeline meets the same quality standards.

The octane of the fuel is tested before it is distributed. If you were mistakenly putting 80 octane fuel in, you would know it immediately. The lowest octane I have seen is the local fuel here in Utha, with a low grade of 85 to compensate for elevation on older carberated vehicles. Fuel injected vehicles still typically require the manufacturer recommended octane of 87. If I put 85 in my van, I know about immediately. It will ping from even mild acceleration. These effects would be even more noticeable at lower elevation.

While pinging does hold merit for destroying a head gasket over time, pray tell, how would you know not know about it. Pinging is an obvious sound.

Ethanol even poorly mixed will not be a death warrant for a 4.0L, and here is why. Ethanol has an octane rating of 107. Mixing it with gasoline has the effect of increasing the fuels octane rating. So your never gonna get a cheapy 80 octane with ethanol added. The only difference between most brands of fuel since 2005 is the add package. The gasoline itself is almost all the same stuff because everyone uses the same refineries. Here in Utah thats not always the case, though the crude all comes from the same place. All our refineries are local, and our pipelines are relatively short. Back east, standardization is greater because the refineries have a higher workload and service a larger area. The oil comes from a variety of places, so you will get a little variation in dissolved impurities, but nothing that will really effect the fuel, since all fuels have to have low sulphur content.

The chances that the quality of fuel is contributing to blown head gaskets beyond occasional flukes I would say is almost non-existent. If you as an individual are having a lot of issues, I would ask firstly, is this the same engine over and over again? If it is, then was the head resurfaced when the gasket was replaced. If not, then duh, the head is warped and is resulting in repeat failures. The block itself can sometimes warp. Not common but it does happen. So if you put a flat head on a warped block, you are going to have repeat failures.

The most common cause of failures is the cooling system. If it is not performing properly, you get poor or uneven cooling, and the head is the first part that will loose cooling because it is the highest, and it takes the most heat because it is always fully exposed to the combustion. So if it looses cooling, it will warp, and can develop enough force in doing so to stretch the head bolts, which will also be weakened by the heat. The solution, keep the head cool.

The way to do that is use the proper coolant with purified water. Do not EVER put tap water in the system. If you do not have access to RO water or distilled water, then buy premixed coolant. It is worth it. Use OEM thermostats, make sure the water pump is working well, replace the coolant every other year at most, burp the system according to the method outlined in the owners manual, use OEM radiator caps, and make sure the temp senders for both the engine and gauge are as accurate as you can. If you do not have a scan tool, checking the ECT sender is hard, but the gauge one should come about 1/3 the way up when the engine is warmed up, if it is lower than that, you have either a bad thermostat, a bad sender, or a bad gauge. If the gauge reads low, you can repeatedly overheat without realizing how hot stuff is actually getting.