so I posted this in the wrong forum so I'm going to paste my original post here. thanks guys and gals


Hey guys and gals I just picked up a 4/98 build date 99 f250 srw 4x4 v10. It had a miss and engine code for #2 coil. I bought 10 spark plugs and a coil. As I was replacing the coil I noticed coolant in #2 and #3 spark plug holes. I blew them out and finished installed the spark plugs. The truck rode out great for about a week and now I feel it missing. Hooked up my Autel and live data shows all ten coils are firing. I’m thinking the plug holes have filled up with coolant and is shorting the firing sequence going to the plugs. I did notice that the crossover tube looks wet so I’m thinking that it’s leaking coolant down the side of the manifold into the plugs. Has anyone else had this issue? It’s currently my daily and I would hate to Down it to find more than just that. I have an all aluminum intake manifold and I had to special order the gaskets from ford. Evidently after 7/98 the gaskets are different. Is this when they switched to the plastic manifold? Any info / advice would be greatly appreciated. Also, along with the misfire I’m noticing average city/ highway mpg is 11.5. Hoping that I the intake fix will bump it up a little bit once I can get rid of this misfire ( freeze frame data speed p0300 random misfire) edit* I also have Lost about 1/4” off my coolant reservoir over the last few days


built on 4-27-1998 for 1999 model year. 6.8 v10 straight axle 4x4 3.73 gears

 

Your good with your original post in the general super duty forum since your truck is a super duty this is just the v10 specific section. It’s relatively quite over here so you’ll get more exposure over there too.

 

The 2-valve V10 never got a plastic intake. I'm not sure about the bottom half of the intake though. Check the heater hoses that pass over/near cylinders 2 and 3. The coolant has to be going somewhere - any white smoke out the tailpipe?

 

it wasn't smoking at all until I treated the fuel with injector cleaner then it would puff whitre smoke, but had no odor of coolant. being that it was also cold.. I mean really cold, for florida I chalked it up as condensation from shutting down a hot engine in "cold" weather here in fl. didn't notice white smoke this morning when I fired the truck up. I ended up fixing the misfire last night. number 5 was showing bad on my scan tool so I replaced it then pulled all 5 cops and used good dielectric type grease to try and kee;p the coolant out of the boots. this truck hasn't ran this good in years. previous owner was an old man who put 6k miles on the truck since 2013. has brand new bfg ko all terrains that are cracked from sun exposure with nipples still on the tread. I am now going through and doing maintenance on the truck that has been neglected.but, not bad for trading my jeep for it.

 

Yeah, I asked about the white smoke just to rule out a bad head gasket. Coolant in the plug holes doesn't mean a head gasket anyway. Something's leaking - or USED to leak until someone fixed it. Find that leak

 

I just replaced #3 cop 2 weeks ago and blew the coolant out of 2 and 3 then, just swapped the new coil in 5 and removed 3 and changed it to cylinder 4 so now the rear most pass. cops have been changed and when I did low and behold, coolant filled both 2 and 3 again. with the cops removed you can see the coolant wetness along the head going right up to the crossover tube. I have the intake gaskets on order from ford, through my work discounts they came out too 40 dollars and some change for left and right intake gaskets. I will be tackling this project this weekend, so lets hope for no more misfires until I get them changed out and blow the plug holes out again.

this has turned into quite the little project but I think its going to be a good truck. I still have yet to drain the front and rear diffs, and transfer case. I have a 4r100 accumulator body spring kit to install as well so when I drop the pan for that I will replace the trans fluid. pcv rattles so I guess that's good, and I just serviced the engine with 5w30 motorcraft semi synthetic. he had 10w40 in it prior and it had degraded quite a bit. not many miles on the oil change, but it was done 4 years prior.

time will tell how long I will have this truck, but like my ol lady says," you sure do fix em right for the next guy."

 

If it is the coolant return tube leaking here was my adventure.

https://www.ford-trucks.com/forums/1...turn-tube.html