In front of me is a $2,600.00+ head job repair bill estimate for my 5.4, the valves are no good and there is leakage. My truck is like a diesel, the tail pipe is black, so the valves must be gunked. I've tried a bottle of GUMOUT, and LUCAS (added to the fuel tank) and they have helped somewhat. I have 132,000 miles and the CEL is constatly throwing the codes P0308 & P0316. Is there anything else I can do because I dont think im gonna fork out the money to fix it...? What about Marvel Mystery Oil?

 

There is an old saying from Smokey Yunick - "Oil is not a wrench." If you have mechanical problems with your engine, nothing you pour into it is going to fix it, the engine will have to be taken apart for repair. Are you sure its the valves? The codes you posted are both about misfires, specifically on the #8 cylinder. Have you done a compression check on that cylinder? Check the basics first, spark, fuel and compression on that cylinder.

 

Yup, no amount of "mystery oil" will substitute for a proper repair. Find out what is causing the codes before dropping money on snake oil.

 

Maybe look at a process called motor vac.

 

Thats a lot of money, check out this link for rebuilt engines that come with a warranty, could be a better option.

http://www.psengines.com/FORD8.htm

 

You seem to be jumping to conclusions. You state that you have a misfire but how do you know you have bad valves? Have you done a compression test or leak down test? I would fix the misfire first then see if you still have problems. A black tail pipe is not a good diagnoses for bad valves. Are you using motorcraft oil filters?

 

Holey cow thats cheep...and includes shipping to you and sending your core back. The rebuilt motor is as much as his repair quote on his heads!

Have you used them before?

 

I have never used them or had any dealings with them. I just did a search for F150 exchange engines & that was the first I picked.

 

Gotcha thanks for the info.

 

The shop did preform a leak down test, and they said the whole bank is bad (which is one whole side of the engine?) They stated the Fuel Injection is working properly and the coil/plug was replaced on cyl#8. I do all my own oil changes with motorcraft filters

 

Thanks, but it sounds good in therory... yes a leakdown test was preformed by a shop, and they said there is leakage by that cylinder, new coil and plug were replaced on cyl 8 as well, and the F.I. is fine