Just how common are blown headgaskets?
 

Hello,
I'm interested in buying a 6.0 diesel over a 7.3. I plan to not spend a ton of money, as a general rule with these motors. More of a budget work truck setup. Without having a professional check it out, what are some signs to look for other than it pushing coolant out of degas bottle. I'd love to check EOT and ECT differentials, and the whole nine yards, but that likely isn't realistic if a deal comes up.

See if you can acquire a Scan Gauge2 to easily plug in on the test drives. Tunes are no good for hg reliability, I wouldn't buy a used 6.0 that had a tune.

My bone stock '06 has 150K miles, purchased used at 5K miles. I knew about the block casting sand clogging the oil cooler so I gave the cooling system a good flush at 10K, then again at 50K. Only big issue I've had was an end tank seal go bad on the stock radiator last month. I tow heavy (past capacity sometimes) and no issues with coolers, HGs, etc.

I get 21mpg hwy and love the truck, I change fluids/filters regularly and use the Ford fuel lube/cetane booster every tank since I bought it. You couldn't pay me to put a tune on it. Look for a well taken care of stock '06 or '07 (those years have a lot of revisions in place). Good luck.

I don't think I would want to buy a used 6.0L without checking the engine parameters. The 6.0L does take some knowledge and awareness to avoid problems. Also needs to have proper maintenance. Power adder mods (depending on how large) can always cause problems if the proper upgrades haven't been done (and done properly). The issue is as much of a distrust of the previous owner(s) as it is the truck - at least for me. Lot's of ways a poorly cared for 6.0L can bite you (fuel pressure and injectors, poor fluid and filter maintenance, wrong coolant, engines running hot, wiring problems and hacked up harnesses, low voltage, etc).

I bought my 6.0 assuming I would have to do head gaskets and a few other things. I drive it like I stole it and it lasted another 40k miles and 2 years before they gave out. Again, I factored in the cost of head gaskets, egr delete, oil cooler etc when I purchased the truck. I wouldn't buy a used 6.0 without factoring in these costs and being happy if you happen to get away with out doing it.

the proness of the failures really depend on the trucks history... there are still alot of untouched 6.0's running around with high mileage and still on their original gaskets... the problem is these trucks got a bad rap they really do not deserve... (most of the problems were actually operator caused too).. that said and like others have mentioned.. Used can be either a blessed event or can be a can of worms... I not trying to scare you away from buying one.. they are a working truck after all and dont like to sit... but when something goes wrong their parts are not cheap to replace. I did buy mine used... and as far as the engine itself goes ive had very few problems... where the majority of mine have been is in the rest of the drivetrain simply because the previous owners didnt bother to really keep up the maintenance... on as close of tolerance vehicles as the superdutys are, maintenance is a BIG factor.. letting the maintenance go just tears up surrounding items and adds even more expense to the repair bills.. its better to taking care of the small problems sooner rather than later..

As to what to look for on the failures, it really depends on how it fails. If it fails between the cylinders you could have low compression across the cylinders. failure between the cylinder and a coolant port could result in steam or a hydro-locked engine if its severe enough. or if it fails like mine did where the coolant port was able to leak directly out of the block youll find coolant trails on the block or puddles on the ground. mine was running down the back side of the block.

Coolant in the oil can be another symptom of head gasket failure... however there other other areas where the 2 could mix as well so not the sole cause.. for instance the coolant/oil heat exchanger cooler is a good place for cross contamination... problem is without being able to see the truck, and run a multitude of tests on it, it can be a gamble. like others have said really get a shop to look at it.

The main reason that I have the opinion that you should expect the gaskets to go, Unless it was your fathers, you have no real idea to know how well it was taken care of and how it was driven. The 6.0 power curve lends itself to be driven hard. My truck even in stock trim is fun to drive and its hard to keep out of the GO pedal. I am sure I am not the only one that pushes a little harder than they would if it was a gasser, its just fun to drive. That being said, you will have no idea how someone drove it if its used.

before i bought mine everyone was telling me if i did go diesel to drive it like i stole it as they do not like being babied on the throttle... its a good way to get the vanes stuck on the turbo if you dont drive it hard and suddenly have to get on it for whatever reason... because the carbon builds up where the vanes are not normally sweeping.. then when you do get on it the vanes end up closing further and get stuck on the thicker buildup..

Absolutely! Preventive maintenance and replacing items before they fail and upgrade as needed go a long way when it comes to keeping a 6.0L happy.

considering in the factory setup the EGR valve computer programming is programmed to open when the throttle is let off id say at least a few.. this programming was done to help dump the excess intake pressure down the EGR cooler and into the exhaust... its been fairly common afterwards for the HG failure after its deletion. while i do say common i also dont mean its the sole reason for it.. as there are a few on here running a 99% stock engine with just the cooler deleted...

the problem is people dont understand that the EGR valve is essentially acting as a remote BOV for the turbo. in addition to this many fail to understand the inner workings of how all the parts work together when modding.. or they attribute the failures to other parts of the engines.. while it is not always the primary cause it does have its effects on the engines that can be added to from other modifications.. most that have deleted the egr didnt do so just by itself they did it in conjunctions with other things.

As far as the cooler failures and HG failures go it really depends on how bad the cooler is leaking... a small leak causing fine mist to be injected into the intake can act like a boost cooler fluid similar to how Snow Performance Meth injection works.. just not as efficient or as measured... but a larger failure can result in the combustion and exhaust system getting flooded till it hydrolocks or blows the gasket.

I agree that the design is "on the edge", but personally I think the problem is more an issue of quality control. Block and head surface condition as well as torquing accuracy. Excessive heat plays a part also, and so does stuck turbos and probably even stuck EGR valves.

Lots of examples like FiznUKa.