P0171 P0174 5.0, oh yeah and some lower intake bolts :-)

[crunchie_frog]

Starting getting P0171 P0174 codes on a 2000 5.0. Forscan showed high fuel trims (~25%) at idle and much less (7% - 10%) at driving rpms. Started checking for vacuum leaks, ended up it was the 3/8" ID line that goes underneath the battery well to the evap canister. So, to anyone searching for possible vacuum leaks on a high mileage 5.0 (this one 261K miles). Check here, it was at the bottom of the hose and I could not see it from the top.

Now the funny part. Sparing you the details, prior to finding the leak I ended up taking the upper manifold off twice and tried taking the lower manifold off once. When I tried taking the lower manifold off, I snapped the 3 bolts just below the surface of the top of the intake, you know the ones. I tried wiggling (1/16 turn) just a little back and forth and so on, in the end, they snapped. I was hoping to pull the intake off but it would not budge (other 9 bolts removed). I ended up pulling up on it with and engine hoist under the intake casting where the thermostat body is enough to lift the vehicle off the ground and the intake did not budge, even while hitting it with a two by four and a sledge while hanging. I am guessing those 3 bolts are frozen inside the intake body. In any case, I put it all back together, no external coolant leaks, no loss of coolant, ran fine other than the same problem, lean codes. Went back to checking hoses and took off the 3/8" ID vacuum hose that goes under the battery well and pulled it off, split on the bottom with about a 2 " uneven crack. I had to drive to 7 different auto parts stores before finding the right size vacuum hose. Replaced the hose, fuel trims near zero, runs great. I hope I learned my lesson, meaning triple check all the hoses before diving into the lower intake! In any case, it is running great without the three intake bolt heads.

So, I am going to keep running it and see how long before the lower intake gasket gives way, it is an in town daily driver. Any bets on miles before (if) the lower intake gasket gives way? Will post when and if it fails.

 

[410Fortune]

ouch

which 3 intake bolts the front two and which other one?
The front two enter the water jacket and corrode making them stuck often. I had to drill one out once...problem was I then broke an easy out off in the bolt. Then I had to drill that out....that was a 3 month ordeal, I kept buying better and better drill bits to drill through the broken ones. Eventually I was able to drill deep enough to create a few threads, like 6 of them so I installed some threaded rod and made a stud allowing me to cinch down the front of the intake with a nut
I drove it like that for years.
I hate those front bolts
The 289 "steel bolts into the water jacket" design goes back to 1969 so I cannot complain too much, I just deal with those two lower intake bolts and the 4 in the timing cover/water pump
I now own a torch and a BOLT BUSTER
heat is the only way to free those corroded bolts

 

[CDW6212R]

Good stuff, bad design/engineers. The early 289's and 302's had four extra intake bolts, out near the corners. The bolts corrode within the aluminum bolt holes, that corrosion slowly bonding the bolt and intake together. I think it happens whether there's a coolant passage there or not, just much faster if coolant reaches the bolt.

So adding anti-seize to the entire bolt length is the best preventative remedy. Coating the bare aluminum would be smart too, besides a thread sealant made for coolant.

I still have my project 98's water pump to work on, one bolt head broke off the first time I worked on it, and I left it. To do that WP, I'm going to yank the engine and rebuild the heads, put them on my spare 92 HO engine, cut one block bolt hole, and drop that in with the Explorer cam, plus the 6R.

 

[crunchie_frog]

ouch

which 3 intake bolts the front two and which other one?
The front two enter the water jacket and corrode making them stuck often. I had to drill one out once...problem was I then broke an easy out off in the bolt. Then I had to drill that out....that was a 3 month ordeal, I kept buying better and better drill bits to drill through the broken ones. Eventually I was able to drill deep enough to create a few threads, like 6 of them so I installed some threaded rod and made a stud allowing me to cinch down the front of the intake with a nut
I drove it like that for years.
I hate those front bolts
The 289 "steel bolts into the water jacket" design goes back to 1969 so I cannot complain too much, I just deal with those two lower intake bolts and the 4 in the timing cover/water pump
I now own a torch and a BOLT BUSTER
heat is the only way to free those corroded bolts

Yes, the two in front and the other one on the rear driver’s corner (ground strap attached to this one. I considered an ez out and or left hand hardened drill but my experience with these is iffy at best. I also was reluctant to try to torch as well. In any case, the intake did not move even the tiniest bit when I lifted up on it. Been driving for a week now with the broken bolts and no issues so far. I put some k-seal in the coolant with hopes of stopping any coolant leaks…. The rear main seal is shot and #8 had some oil residue in the intake so that cylinder maybe losing compression meaning at some point the engine is coming out anyway so I am hoping it holds on. 261K miles, so I feel like I got my money’s worth. Bought it used with 180K miles 7 years ago. Anyway, thanks for the info and tips…

 

[crunchie_frog]

Good stuff, bad design/engineers. The early 289's and 302's had four extra intake bolts, out near the corners. The bolts corrode within the aluminum bolt holes, that corrosion slowly bonding the bolt and intake together. I think it happens whether there's a coolant passage there or not, just much faster if coolant reaches the bolt.

So adding anti-seize to the entire bolt length is the best preventative remedy. Coating the bare aluminum would be smart too, besides a thread sealant made for coolant.

I still have my project 98's water pump to work on, one bolt head broke off the first time I worked on it, and I left it. To do that WP, I'm going to yank the engine and rebuild the heads, put them on my spare 92 HO engine, cut one block bolt hole, and drop that in with the Explorer cam, plus the 6R.

Yes, I am hoping the aluminum / steel bolt bond continues to hold. And yes, there must be a better design like maybe steel inserts in the bolt holes in the intake and the timing cover. Otherwise, these 5.0 are battle hardened and run forever so I have no complaints Take care!

 

[CDW6212R]

Keep driving it, I'd bet on the intake holding as long as the rest stays together. My WP finally began to make noise, so I had to stop driving it, I had gone almost a year without 3rd and 4thg gears, plus the AWD locked up. These are great trucks.