Notices

351W Block Question

Thread Tools
 
Search this Thread
 
Old Dec 15, 2018 | 11:29 AM
  #1  
93OBS's Avatar
93OBS
Thread Starter
|
New User
Joined: Dec 2018
Posts: 11
Likes: 0
351W Block Question

1993 F250 351W. Stock exhaust.
Hello to the list.
I can't seem to describe this correctly so starting a new thread. When looking for the chronic right side exhaust leak the muffler shop said I was missing a bolt. The photo (not my motor) shows the 'hole' I think he was talking about and it looks to be threaded. I dropped the fender well liner to see and it looks like 'something' is missing. Motor runs fine except for the exhaust leak. Any one have a clue as to what should go there? The local Ford dealer didn't and I can't find anything on the net.
Thanks, Steve
 
Attached Images  
Reply
Old Dec 15, 2018 | 12:42 PM
  #2  
NumberDummy's Avatar
NumberDummy
Ford Parts Specialist
Joined: Nov 2006
Posts: 88,826
Likes: 784
From: Simi Valley, CA
Club FTE Gold Member
What's on the other side?

There's a thermactor (smog pump) tube that runs across the back of the engine from head to head. It tends to rust out, so it may be missing.

See 9B449 at left in pic. This is 1988/89, but 1990/96 will be similar.


 
Reply
Old Dec 15, 2018 | 01:38 PM
  #3  
93OBS's Avatar
93OBS
Thread Starter
|
New User
Joined: Dec 2018
Posts: 11
Likes: 0
Thanks for the quick reply. The crossover tube from head to head is intact although hard to see it's condition. This hole(?) is on the block but it's raining so I can't see yet what's on the other side. However I have come across a couple of rear views and that 'hole' might just have a plug in it but can't really tell. Whatever was there is definitely missing.
 
Reply
Old Dec 15, 2018 | 02:12 PM
  #4  
schoo's Avatar
schoo
Logistics Pro
10 Year Member
Liked
Loved
Community Favorite
Joined: Mar 2012
Posts: 4,389
Likes: 42
From: placer county usa?
I’m no expert but on my 89 302 there is a knock sender near that spot
 
Reply
Old Dec 15, 2018 | 02:24 PM
  #5  
schoo's Avatar
schoo
Logistics Pro
10 Year Member
Liked
Loved
Community Favorite
Joined: Mar 2012
Posts: 4,389
Likes: 42
From: placer county usa?


knock sensor above hole like you have no plug
 
Reply
Old Dec 15, 2018 | 02:58 PM
  #6  
93OBS's Avatar
93OBS
Thread Starter
|
New User
Joined: Dec 2018
Posts: 11
Likes: 0
Great, thanks for the photo. Looks like the same hole so you're saying there is nothing in your's? It's a dummy hole dead end?
 
Reply
Old Dec 15, 2018 | 03:12 PM
  #7  
schoo's Avatar
schoo
Logistics Pro
10 Year Member
Liked
Loved
Community Favorite
Joined: Mar 2012
Posts: 4,389
Likes: 42
From: placer county usa?
Originally Posted by 93OBS
Great, thanks for the photo. Looks like the same hole so you're saying there is nothing in your's? It's a dummy hole dead end?
302 is a different block but holes look the same the hole in mine just goes into the bell housing area I think it was for support bracket for air tube that ND was talking about I checked other pictures of my engine and there was nothing in it
 
Reply
Old Dec 15, 2018 | 04:28 PM
  #8  
Conanski's Avatar
Conanski
FTE Legend
15 Year Member
Photogenic
Photoriffic
Community Builder
Joined: Jun 2006
Posts: 31,930
Likes: 1,499
From: Ottawa, Ontario
That may be a knock sensor hole but it could also be for mounting the clutch bracket or something, in either case it's a blind hole and it's in the block so it has absolutely nothing at all to do with the exhaust so it's not your problem... you could have a cracked exhaust manifold or a leak in the thermactor(air injection) system.

Here is a pic of the rear of a 1/2 ton 5.8 motor and the crossover tube, this assembly should be rigid and a good test is to reach in over the motor and grab the hose and give it a good shake. It should not move, if you break it it was rusted out anyway. Chances are this is the source of your exhaust leak.


 
Reply
FTE Stories

Ford Trucks for Ford Truck Enthusiasts

story-0

Top 10 Ford Truck Tragedies

 Joe Kucinski
story-1

AEV FXL Super Duty - the Super Duty Raptor Ford Doesn't Make

 Brett Foote
story-2

Lobo Vs Lobo: Proof the F-150 Lobo Should Be Even Lower!

 Michael S. Palmer
story-3

Ford's 2001 Explorer Sportsman Concept Looks For a New Home

 Verdad Gallardo
story-4

10 Best Ford Truck Engines We Miss the Most!

 Joe Kucinski
story-5

2026 Shelby F-150 Off-Road: Better Than a Raptor R?

 Brett Foote
story-6

2027 Super Duty Carhartt Package First Look: 12 Things You NEED to Know!

 Michael S. Palmer
story-7

10 Most Surprising 2026 Ford Truck Features!

 Joe Kucinski
story-8

Top 10 Ford Trucks Coming to Mecum Indy 2026

 Brett Foote
story-9

5 Best / 5 Worst Ford Truck Wheels of All Time

 Joe Kucinski
Old Dec 15, 2018 | 05:13 PM
  #9  
93OBS's Avatar
93OBS
Thread Starter
|
New User
Joined: Dec 2018
Posts: 11
Likes: 0
Thanks again Roy for your info. Since the weather cleared it inspired me to poke around with a long welding rod and it is indeed a blind hole. Should have done that first. Going to have a chat with my muffler guy. I will respond to conanski and rap this thread up.
Steve
 
Reply
Old Dec 15, 2018 | 05:38 PM
  #10  
93OBS's Avatar
93OBS
Thread Starter
|
New User
Joined: Dec 2018
Posts: 11
Likes: 0
Thanks for the input Paul. As I replied to schoo it is a blind hole so I will forget about it. I didn't think it was part of my exhaust issue but was led to believe that a bolt was missing or broken and haven't found any others (yet). Just wanted to replace something if needed. I have assumed that the ex. manifold was the problem for a while now but will give the crossover tube the grab test when I can. If that is the source of my exhaust leak then I will gladly take it as opposed to a bad exhaust manifold. I'm new here and sure to have other issues but we can put this thread to bed.
Thanks again everyone,
Steve
 
Reply
Old Dec 17, 2018 | 12:04 AM
  #11  
fordman75's Avatar
fordman75
Lead Driver
25 Year Member
Photogenic
Photoriffic
Liked
Joined: Dec 2000
Posts: 6,289
Likes: 47
From: South central, Minnesota
My 96 5.8L has a nasty exhaust leak on the right side. It was bad enough I thought I had a cracked manifold. But it was the EGR supply pipe rusted thru. So don't over look that when you've got a exhaust leak. That's at the front of the right manifold on mine. But I don't know if that's the location where yours is leaking. But make sure to check that out. You can get a new one if your is bad too.
 
Reply
Old Dec 20, 2018 | 05:49 PM
  #12  
93OBS's Avatar
93OBS
Thread Starter
|
New User
Joined: Dec 2018
Posts: 11
Likes: 0
Thanks for your thoughts on this. I have heard about the EGR tube so I planned on checking it when weather cleared. Was going to do the 'grab test' on the head to head crossover tube but can't reach it from the top. So I took it to another muffler shop and he didn't mention any broken or missing bolts but said the back two exhaust ports have soot around them so that must be it. Oddly he said the gasket is leaking but my understanding was that they didn't use exhaust gaskets. Looking like a bad manifold, crap.
 
Reply
Old Dec 20, 2018 | 06:38 PM
  #13  
Conanski's Avatar
Conanski
FTE Legend
15 Year Member
Photogenic
Photoriffic
Community Builder
Joined: Jun 2006
Posts: 31,930
Likes: 1,499
From: Ottawa, Ontario
Yeah no gasket used normally but the manifold mating surface must be perfectly flat. You could have a couple broken bolts on that manifold, they will corrode so bad the heads remain stuck in the manifold.
 
Reply
Old Dec 20, 2018 | 07:13 PM
  #14  
fordman75's Avatar
fordman75
Lead Driver
25 Year Member
Photogenic
Photoriffic
Liked
Joined: Dec 2000
Posts: 6,289
Likes: 47
From: South central, Minnesota
It's pretty common for a gasket to be installed when engine work is done. That's just easier/cheaper then having everything machined again.
 
Reply
Old Dec 21, 2018 | 08:25 AM
  #15  
baddad457's Avatar
baddad457
Hotshot
20 Year Member
Liked
Joined: May 2003
Posts: 11,141
Likes: 25
From: south louisiana
Originally Posted by fordman75
My 96 5.8L has a nasty exhaust leak on the right side. It was bad enough I thought I had a cracked manifold. But it was the EGR supply pipe rusted thru. So don't over look that when you've got a exhaust leak. That's at the front of the right manifold on mine. But I don't know if that's the location where yours is leaking. But make sure to check that out. You can get a new one if your is bad too.
My 96 had a leak on the passenger side too. Van came from Iowa. My guess is that snow/ice buildup occurred here with road salt that caused the manifold to corrode from the salt.. I replaced them with shorty headers when I did the GT40 head swap. Bolts came loose easily when I did the swap.
 
Reply



All times are GMT -5. The time now is 08:52 PM.

story-0
Top 10 Ford Truck Tragedies

Slideshow: Top 10 Ford truck tragedies.

By Joe Kucinski | 2026-05-18 19:34:33


VIEW MORE
story-1
AEV FXL Super Duty - the Super Duty Raptor Ford Doesn't Make

And it might be even better than that.

By Brett Foote | 2026-05-18 19:26:42


VIEW MORE
story-2
Lobo Vs Lobo: Proof the F-150 Lobo Should Be Even Lower!

Slideshow: Does lowering an F-150 Lobo RUIN the ride quality?

By Michael S. Palmer | 2026-05-18 19:20:37


VIEW MORE
story-3
Ford's 2001 Explorer Sportsman Concept Looks For a New Home

Slideshow: Ford's bizarre fishing-themed Explorer concept has resurfaced after spending decades largely forgotten.

By Verdad Gallardo | 2026-05-12 18:07:46


VIEW MORE
story-4
10 Best Ford Truck Engines We Miss the Most!

Slideshow: The 10 best Ford truck engines we miss the most.

By Joe Kucinski | 2026-05-12 13:09:47


VIEW MORE
story-5
2026 Shelby F-150 Off-Road: Better Than a Raptor R?

Slideshow: first look at the 810 hp 2026 Shelby F-150 Off-Road!

By Brett Foote | 2026-05-12 12:50:07


VIEW MORE
story-6
2027 Super Duty Carhartt Package First Look: 12 Things You NEED to Know!

Slideshow: Everything You Need to Know about the 2027 Super Duty Carhartt Package!

By Michael S. Palmer | 2026-05-07 17:51:06


VIEW MORE
story-7
10 Most Surprising 2026 Ford Truck Features!

Slideshow: 10 most surprising Ford truck options/features in 2026.

By Joe Kucinski | 2026-05-05 11:17:22


VIEW MORE
story-8
Top 10 Ford Trucks Coming to Mecum Indy 2026

Slideshow: Here are the top 10 Fords coming to Mecum Indy 2026.

By Brett Foote | 2026-05-04 13:49:49


VIEW MORE
story-9
5 Best / 5 Worst Ford Truck Wheels of All Time

Slideshow: The 5 best and 5 worst Ford truck wheels of all time

By Joe Kucinski | 2026-04-29 16:49:01


VIEW MORE