Author Topic: Would a reasonable guy do this?  (Read 6347 times)

Offline Combat Veteran

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Would a reasonable guy do this?
« on: January 09, 2018, 03:52:09 PM »
I have had the 1987 350 tbi truck into the shop for a new intake manifold gasket. Since then it has been back due to excessive leaking (oil). Replaced the distributor gasket, dry, return 1. Tightened valve covers, dry return 2. Tightened oil sending unit, dry, return 3. Still finding oil on top dripping down the sides. I have an appointment to have the intake gasket job redone. Should I get a new manifold so I can rule out the old one is possibly warped or otherwise damaged since it is 30 years old? Paid $500 for labor the first time, mechanic making good for it this time.   

Would like a sanity check before I pull the trigger on another $350 manifold.
1987  slightly modified Custom Deluxe V10, 350TBI, 700R4,  NP208, 4X4,  4.42 gears,  33" Firestone Destination M/T

Offline VileZambonie

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Re: Would a reasonable guy do this?
« Reply #1 on: January 09, 2018, 05:10:49 PM »
It's a workmanship issue, let him take care of it. If he can't resolve it, take it somewhere else reputable.
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74 GMC, 75 K5, 84 GMC, 85 K20, 86 k20, 79 K10

Offline Combat Veteran

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Re: Would a reasonable guy do this?
« Reply #2 on: January 09, 2018, 06:19:52 PM »
If it's a bad manifold, I have to pay another mechanic to do the job and new manifold. Is it possible the manifold is not the issue, just the way it was installed?
1987  slightly modified Custom Deluxe V10, 350TBI, 700R4,  NP208, 4X4,  4.42 gears,  33" Firestone Destination M/T

Offline bd

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Re: Would a reasonable guy do this?
« Reply #3 on: January 09, 2018, 07:37:48 PM »
...Still finding oil on top dripping down the sides....

I agree with Vile on workmanship issues.  Still, tell us more about this.  Where on top do you see oil accumulation and from where is it dripping?  Unless the manifold is broken or obviously cracked (an unlikely scenario regardless of age), the problem is a compromised gasket or seal - probably along the china wall, or cracked OPS fitting adjacent to the distributor.  I would snap pictures before taking it back in for repair and compare them with what I got back.
Rich
It's difficult to know just how much you don't know until you know it.
In other words... if people learn by making mistakes, by now I should know just about everything!!!
87 R10 Silverado Fleetside 355 MPFI 700R4 3.42 Locker (aka Rusty, aka Mater)

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Re: Would a reasonable guy do this?
« Reply #4 on: January 09, 2018, 08:02:32 PM »
Oil was dripping from the top and bottom of the engine when I bought it. We started addressing the issues from the top. The intake manifold gasket was replaced first. Got it back and immediately appear to leak worse. Then the rear main seal was replaced. Got it back and was better but still leaking. Oil was still coming from up top, appeared around the distributor, so that was double gasketed. That did not solve the leak, but it is dry around the distributor. Still wet around the top back side. Then it was determined that the fitting where the oil pressure sensor goes into the block was leaking from around the threads. Teflon taped the threads and now that was dry. Oil still found on the top of the block, apparently coming from the intake gasket, mostly leaking from the drivers side back corner. Enough that it drips down the sides and along the bottom of the bell housing inspection cover and a small puddle on the floor. I simply can't see where the oil is coming from.

I wanted to give them the benefit of the doubt that it was not poor workmanship, but a bad manifold. I am losing my patience, since the truck had a very nice $10K paint job, and every time I see them leaning into the engine compartment, there is more opportunity for them to damage it. I already see some fine scratches on both sides, just from the protector they use.
1987  slightly modified Custom Deluxe V10, 350TBI, 700R4,  NP208, 4X4,  4.42 gears,  33" Firestone Destination M/T

Offline bd

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Re: Would a reasonable guy do this?
« Reply #5 on: January 09, 2018, 08:36:57 PM »
Honestly, there is no reason to reach in over the fenders.  In fact, it is awkward to do so.  The intake manifold is easiest to replace from the front of the vehicle while sitting on the radiator.  That said, ask the shop to use good cloth fender coverings. 

If you look closely, you will probably find oil seeping past the rear china wall seal, especially if the shop used the cork gaskets instead of throwing them away and substituting high-quality silicone sealer.  Getting a good seal along the china wall is mostly a matter of preparation and applying a suitable bead of silicone before dropping the manifold straight down w/o sliding it.
Rich
It's difficult to know just how much you don't know until you know it.
In other words... if people learn by making mistakes, by now I should know just about everything!!!
87 R10 Silverado Fleetside 355 MPFI 700R4 3.42 Locker (aka Rusty, aka Mater)

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Re: Would a reasonable guy do this?
« Reply #6 on: January 09, 2018, 09:18:30 PM »
I'll pass these points along to the mechanic. Hopefully the second times a charm and it doesn't cost me a new manifold. Are any gaskets out there superior to another?
 
1987  slightly modified Custom Deluxe V10, 350TBI, 700R4,  NP208, 4X4,  4.42 gears,  33" Firestone Destination M/T

Offline bd

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Re: Would a reasonable guy do this?
« Reply #7 on: January 09, 2018, 09:40:55 PM »
Everybody has their favorite.  I use Fel-Pro almost exclusively and prefer Printoseal intake gaskets along with Ultra Grey or Ultra Copper silicone for the ends and around the coolant ports.  I also coat the intake bolt threads with ARP PTFE Thread Sealer or Permatex Thread Sealant with Teflon.  Again, thread and gasket surface preparation are key.
Rich
It's difficult to know just how much you don't know until you know it.
In other words... if people learn by making mistakes, by now I should know just about everything!!!
87 R10 Silverado Fleetside 355 MPFI 700R4 3.42 Locker (aka Rusty, aka Mater)

Offline bd

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Re: Would a reasonable guy do this?
« Reply #8 on: January 09, 2018, 10:08:31 PM »
I should add that the only way to know from where the leak is originating is to look closely and conscientiously.  Using dye may benefit if the leak is particularly evasive.  Until the source is verified, any armchair input is merely hearsay.  Your mechanic will have to make the final determination.
Rich
It's difficult to know just how much you don't know until you know it.
In other words... if people learn by making mistakes, by now I should know just about everything!!!
87 R10 Silverado Fleetside 355 MPFI 700R4 3.42 Locker (aka Rusty, aka Mater)

Offline roger97338

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Re: Would a reasonable guy do this?
« Reply #9 on: January 18, 2018, 07:44:00 AM »
China wall? The space between the lower rear of the intake manifold, and the upper rear gasket surface of the lifter galley? Because of it's size or shape? Or have some of you been having Mongolian invader problems in your engine bays?

Offline NCali

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Re: Would a reasonable guy do this?
« Reply #10 on: January 20, 2018, 11:11:22 PM »
call it what you want ,there are only a few places for oil to leak in that area. A bad oil pressure sending unit or cracked threads on the pipe that it screws into
and under the intake and as everyone else has said Do not use the supplied gaskets as they slip use silicone
Black Labs Matter

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Re: Would a reasonable guy do this?
« Reply #11 on: January 22, 2018, 11:27:30 PM »
Getting the truck back tomorrow. New Edelbrock 3407 intake manifold, gaskets, etc. I found the thread about letting the vehicle sit, then final torque, then rest again. Waiting the 24 hours to ensure the sealant is dry before adding fluids and starting. Keeping fingers crossed the leak is gone in the morning.
1987  slightly modified Custom Deluxe V10, 350TBI, 700R4,  NP208, 4X4,  4.42 gears,  33" Firestone Destination M/T

Offline Combat Veteran

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Re: Would a reasonable guy do this?
« Reply #12 on: January 23, 2018, 01:00:04 PM »
Well after installing the new intake, gaskets, RTV and waiting, the engine is still leaking and they are now saying a hair line crack in the block where it meets the intake manifold. They are replacing the seals again today and using the gaskets instead of RTV on both ends, regardless of the Edelbrock instructions. Already making plans to get a new motor. Any suggestions for good mileage and towing capacity?
1987  slightly modified Custom Deluxe V10, 350TBI, 700R4,  NP208, 4X4,  4.42 gears,  33" Firestone Destination M/T

Offline VileZambonie

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Re: Would a reasonable guy do this?
« Reply #13 on: January 23, 2018, 04:39:33 PM »
Did they pinpoint it with dye tracer? Speculation? Sounds like these guys don't know what they're doing. You never use the end seals.
,                           ___ 
                         /  _ _ _\_
              ⌠ŻŻŻŻŻ'   [☼===☼]
              `()_);-;()_)--o--)_)

74 GMC, 75 K5, 84 GMC, 85 K20, 86 k20, 79 K10

Offline bd

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Re: Would a reasonable guy do this?
« Reply #14 on: January 23, 2018, 05:10:05 PM »
I've never seen a block crack in that area either without the rotating assembly grenade.  If they insist on the existence of a crack, politely ask to see it.
Rich
It's difficult to know just how much you don't know until you know it.
In other words... if people learn by making mistakes, by now I should know just about everything!!!
87 R10 Silverado Fleetside 355 MPFI 700R4 3.42 Locker (aka Rusty, aka Mater)