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Discussion Starter · #1 ·
Hey guys,
A friends truck is down and he asked me to look at it. It's not in town so I haven't made it out there yet to look at it. Symptoms are a mis detected in number 6, and white smoke from the tailpipe.
I know there is some diagnosis to be done. I don't know the condition of the oil, or what the spark plug looks like, or the compression of the cylinder, or if there are combustion gasses in the coolant, etc.
But my question for now - is there a common problem here? Are intakes known to crack? Common intake or head gasket failure? Common head cracks?
 

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5.4 is a good motor. Unless he overheated the crap out of if, there should not be a head gasket problem. Are you sure its smoking or is this normal condensation. Bad coils are very common on the fords. I seem them daily with bad coils. That motor uses a MLS gasket so the gaskets dont blow out. If antifreeze is getting into the combustion chamber, the head is warped or cracked.
 

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Discussion Starter · #4 ·
Thanks for replies. So I'm told that number 6 has a misfire, that they put a new coil and spark plug in number 6. First thing I notice is that he put a new coil and spark plug in number 5 instead of 6. Either he swapped out the wrong cylinder or told me what the computer read wrong. I pulled number 6 and I haven't talked myself into thinking its coolant fouled. The ground strap is rusted, and the plug is due for replacement, with some white powdery build up, but nothing over the top. Does any one have a pic of a plug that's coolant fouled? I forget what that looks like.

I forgot my multimeter so didn't test the coil, and he didn't leave his keys in the truck so I dunno about the smoke. So more diagnosis...

But I did get the rest of the story: It overheated while he was mudding, so he threw some water all over the engine to cool it off. Last I heard that isn't a good idea. Low coolant was the initial cause of overheating, and he didn't notice the white smoke until later.
 

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Racing Jake, you lost me. What are you talking about?
C.O.P. - Coil on Plug. Compressed air to blow all the crud out of the hole in the head from around the spark plug, before removing the plugs.

Maybe it's time for a new set of plugs and coils? How many miles on the engine and current plugs?
 

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:eek: When you go back the first thing you will need is a "rectal extractor" to remove your friends head from between his legs. If he dumped water on it he could have easly warped or cracked the head or the block. Does he take the truck mudding a lot?
 

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Discussion Starter · #9 ·
I don't know the guy - I work with his grandpa and that's who I'm talking to, so my info is kind of 3rd hand. I think its a '97 F250.
I went back over and tinkered, but I want to get a computer on it to confirm the misfire is in number 6 before I tear into anything (I suspect he meant 5).
Coil for 5 and 6 both checked on the high side of OK in resistance. The plug for number 5 looked pretty suspicious - resembled a plug in a motor that has run fuel additives, but only number 5. Had a lot of build up on the ground strap to the point of being mishapen.
Besides that I found that my compression gauge doesn't work for this as the threads are too short.
As a side note, I started the engine. Sounds pretty rough. I witnessed an excessive amount of white smoke, and an excessive amount of antifreeze leaking out the y pipe joint from the drivers side, and from the muffler and tailpipe. The cooling system pressurizes quickly and smells of combustion. YAY. Think you might be on to something with the rectal extractor!
 

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Discussion Starter · #10 ·
I'm having trouble diagnosing this. I would really appreciate any thoughts!

I brought a code reader with me today. Read codes before starting, had a mis in 4 and 6. I deleted these codes. 4 came back, but 6 didn't. Neither come back consistently. But it runs rough, and you can tell that the mis is always present.

Besides that, there are weird things going on with the coolant temp sensor. First it took at least 15 minutes of idling to get any reading on the gauge at all, then it appeared to be normal. Then I put the truck in gear and was backing out of the garage (to see if the misfire readings would come back under load). Suddenly, the temp gauge was maxed out. Of course I kill the engine - but there are no tell-tale signs of overheating. No boiling coolant. I can grab and hold the radiator hose. So I get back in the truck and turn the key to "on". The gauge shows at normal operating temp (and it had only been maybe 1 minute since I shut it off). It never went back up, and seemed that it cooled off REALLY quickly. In short I don't believe anything it says.

So then when I shut the engine off the last time, I hear a whistle. 2 or 3 bursts. Then a sound of pressure relieving but I can't tell quite from where. Roughly thermostat housing area. I grab the upper radiator hose and it is just warm to the touch, but overly tight with pressure. WHen I loosen the overflow cap, there is a lot of air pressure escaping. Coolant bubbled into the overflow somewhat violently, but then as I continued opening it slowly it all drained out into the motor. When it was all said and done the upper hose was relieved of pressure but was dry, had no coolant in it. The system showed full when I started, and is low now. Still no oil contamination.

Am I being overly zealous in jumping to cracked or warped head or block? Seems to me compression is leaking into the coolant, but its not overheating. A lot of white smoke was visible from the tailpipe until it got warm, and it mostly cleared up at normal operating temp. MOSTLY.

Sorry for the novel. I will try to find a compression gauge next time - mine won't screw into the holes, the threads are too short I think.

I WELCOME ALL IDEAS!
 

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Air traped in the cooling system will cause the eratic temp readings you are seeing, could also be electrical problem from dumping water on the engine but most likley the first. Look for a high point on the engine to vent the cooling system some have them labeled not sure on the 5.4. White smoke, missfire, over pressureized cooling system... Somthing is warped, cracked, or blown. Weather it is the head, block, intake, or a gasket only you can figure that out as you have access to the truck. Did you clean the spark plug holes out?
 

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Discussion Starter · #12 ·
Yep, sure did blow the spark plug holes out.
The engine has 239,000 miles on it. I'm thinking it may be best to swap in a younger long block. I can see this costing more than a long block from the pick and pull pretty easily. But would still like to get a diagnosis and let the guy make a decision. I didn't make it over there tonight. I'll have to tear it up this weekend.
 
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