Hello, this is my first post.

Long story short: just bought an 03 f150 xl 4.6 W 5 speed 4wd with 145K that ran really sweet on a test drive and everything checked out to me. All I had to do was clean the throttle body to get rid of the service engine light.

My previous truck, a 98' with about the same specs, had the coolant leak issues that are common and, thanks to this site, I was able to fix all of them until I got tired of fixin *****.

I noticed today that their was a good amount coolant down in the v of the motor and I have no time to pull the intake and look at that stupid pipe. Coolant leaking out the back of the motor. I took it to a "reputable mechanic" and he called me up after inspection and told me the head was cracked and that, because of the mileage, I should get a new motor. Needless to say i brought it home.

Here's the kicker: It runs and shifts fine with no acceleration issues and no missing, bucking, or shaking. It does not get hot. no lean codes no nothing. Except for a horribly uncomfortable bench seat there aint nothing wrong that I can see.

Even if there is a patch job, the way it runs and the price I got it for wont justify this. Have any of you ever had a mechanic tell you this? And, should I see what the dealer has to say?

Like I said I am new to this site and just browsing it has helped me a lot in the past.

 

How did he determine it was a head crack? What kind of test did he do to determine that? How long have you had it and what does the dealership have to say about this issue? You need someone else to look at it and give you their opinion also.

 

145K miles is nothing these days. You need to follow Spottys suggestion. It apparently is an EXTERNAL leak if its in the VEE.. NOT A HEAD CRACKED.... probably something like the pipe you had (or manifold gasket) on the last truck.

 

Heads cannot crack on the intake side where they are paper thin? Interesting.

 

Can you explain what you mean.

 

comment was not directed at you. I have had heads crack on intake side through to a water jacket. Water then ends up in valley.

 

Thanks for the reply.

Ive had it two weeks. driven it about 300-400 hundred miles and the leak started two days ago, no other problems just a power steering whine that ill eventually get around to. The dealership is packed today so my second opinion won't come until monday or tue. If i get a couple hours today ill go out and pull the intake. I didn't ask the mechanic what tests he ran because I would have gotten real chippy. I have a problem with mechanics that have a vehicle for a couple of hours and immediately run to cracked heads and new motors.

The main reason I posted was to see if anybody had heard of head failure dumping A LOT of coolant into the V. Of other vehicles ive had or been around with bad heads and gaskets, it becomes real apparent real fast, and to be honest I have little experience with heads and head gaskets.

 

I'm an older guy and tend to keep stuff way too long thru out my life. I have seen many headgasket issues... coolant internal, coolant external, and oil leaks. None have ever been an immediate gusher, more of a weep. I have had the "V" leak on a couple and one was the crossover was cracked underneath on the intake by the thermostat ( that was a Mustang with the older type intake ....all composite.) The other was that little stub hose behind the water pump stub hose . Another Mustang completely blew the intake open on that front crossover while chasing a Firebird in 3rd gear with my rev. limiter disabled....that was IIRC my 97 GT with just a composite crossover. LOL....I may have contributed to that one though.


It may turn out to be a head, but make sure you check all the other stuff and check it as best you can. No one likes pulling heads on these things.

 

Thanks for the info spotty. I siphoned out the coolant in the v as best I could and I did see a noticeable amount more after I drove around the block a couple times. I'll pull out the intake or have a trusted friend to do it. it sucks not having the time. The oil looks fine and there are no other signs that coolant is "in" the engine.

I was just wondering if there are common places where heads on 4.6s fail. if anything, im just curious.

 

anything is possible, but it is more likely a gasket, manifold, or connecting tube.

 

heads are not "paper thin" at any point a round the manifold. A head will not "crack" for no reason. IT has to run out of water and get very hot, then quenched. You could get a pin hole thru the casting if you have VERY POOR antifreeze. Under normal operation, the head can not crack.... Under normal operation you can have a manifold , gasket , or hose failure. Original post said nothing about severe overheating.

 

You all do know there is a coolant line that runs from the front of the bloc in the valley to the rear and out the back side!.
It may not be the leak but is a good suspect.
Good luck.

 

Bluegrass, I know about the line under the intake. This is my second F150 with a 4.6. And I now get why most of these forums are about coolant leaks and misfires on #4 and #5. I really don't know much about any other motor besides the I6 258 in Jeep CJs but I am well schooled on the Tritons now. The only reason I posted was to see if anybody had ever had a diagnoses like this from a mechanic or about head failure (where) in another truck.

Steve, easy question here... would overheating be a continual problem? because it hasn't gotten close under freeway speeds.

Thanks everybody for the responses on my first post

 

Cracked heads cause drivability issues. You also do further testing like compression tests and leakdowns to condemn a head prior to making that diagnosis. Without that, I'm with everyone else, it's the tube or the intake.

From the tech's point of view, here's the issue - if you want them to tear down far enough to condemn the intake (if it's a rear leak especially) or that tube, that's going to be just as expensive as an intake replacement. They don't want to tell you it's the intake or the tube and have it be the engine (if they even know about these issues - if they're young they may not as these models are 12+ years old now). Generally when asked for 5 hours of teardown time to make a diagnosis, customers balk. So what's the solution from a business perspective? Make sure it's nothing simple. Once it's down to these three things, call the motor, which will replace everything else right along with it, and be sure you've got it right. Terrible but true. I don't do it that way, but I have a lot of people take it up the road because of that. Nobody likes to pay diag time anymore, especially not teardown diag time, even though it would often save them money in the end.

My suggestion is to either make the time to take the intake off yourself or find a technician that's ASE Certified in Engine Repair and Engine Diagnostics (A1, A8) and get a real diagnosis. There's no secret way to check these items with the intake on unless you have a compression leak as well which rules them out as the cause, so if you're running good and the intake's on, there's no way they can possibly rule out these cheaper alternatives.

 

Steve, easy question here... would overheating be a continual problem? because it hasn't gotten close under freeway speeds.----------

overheating occurs when you run low on antifreeze or have no circulation. Lets say you had a radiator hose fail and run the more WAY HOT with no fluid... That stress can crack a head. If the fan belt failed and you continue to run until the gauge is pegged out RED, it is possible to crack the head... If you run water instead of antifreeze, it is possible to rot or corroded the inside and maybe get a pin hole thru the head........... all of those assume you have run the motor out of antifreeze and continue to run until you damage the motor........ Since you said nothing about it ever overheating, and the "leak" just appeared for no reason, I assume it is a tube, gasket or cracked intake.