Upper intake manifold

[patoford]

Hi,
I have a 1999 ford ranger xlt 4.0L that just had the "check engine" light come on. took it to the shop and they diagnosed upper intake manifold leak (code P0171/0174). Recommended replacing for $850. that's a lot of beer (and tools I don't own yet) so figured I'd tackle myself thanks to finding this very helpful forum.
Has 120k miles on it. Have seen other folks needing to replace upper manifold gaskets numerous times (instead of replacing whole manifold).
Question: would it be better to replace the upper manifold (since its plastic) instead of just the gaskets).
also are there other maintenance items that can be done with the manifold off (injectors, lower manifold?)

Thanks!

 

[974X4BLACKSPORT]

What engine do you have? OHV or SOHC? Gaskets is all the dealer did to our OHV, they put the UIM back on dirty didnt even try to clean it, but at least they did the gaskets.

 

[patoford]

it is a OHV. thinking gaskets is all that is needed after reading through the forum (hopefully)

 

[410Fortune]

Yes new gaskets you should replace the upper plenum O rings and the EGR tube O ring
I charge $200 for this at my shop and it takes me about an hour total, gaskets are like $20
$850 is INSANE for an OHV
I charge $500 labor to change the ENGINE

 

[patoford]

Thanks for the info 410Fortune. they did have some extras on the estimate such as cleaning the lower intake and injector reseal but still seems pretty steep. Would you recommend I do that also since its apart?
Also, the gasket kit I ordered comes with a larger gasket as well as the upper plemum O ring. Assuming that gasket covers the area not included under the O ring?

 

[410Fortune]

Where the plastic intake meets the metal fuel rail is where the plenum O rings go. These O rings dry up and shrink over the years, (ethenol fuel does not help). This allows air and dirt into your engine and that is where the big leaks are.
The larger gasket likely goes under the fuel rail between the lower intake manifold and the fuel rail.
Yes it is a good idea to pull the fuel rail and replace that gasket as well, along with the fuel injector O rings
While the injectors are out you can bench test/clean them

New injector O rings are avail from Fel Pro or BWD in packs of 2, you will need 12 "O" rings total, 2 for each injector

Cleaning the lower intake, the gasket mounting surfaces, the fuel rail and upper intake gasket area's is all a part of the job if you want to do it properly.

I use many q tips and carb cleaner to clean the lower intake where the fuel injectors sit (cups) and the entire fuel rail
I use small rags to clean everything else and a small vacuum to remove all loose debris and dust from the areas

I use a jumper box (12V battery) and a simple adapter I made to power up/activate and spray carb cleaner through each injector (bench test/clean)
I use vaseline on the new injector O rings so the fuel rail will stab easily without pinching any O rings
Also vaseline on the EGR O ring, so it slides in smoothly
Vaseline is nice because it is soluble in gasoline
Good time to inspect and repair any old brittle plastic vacuum lines

Still $200 at my shop Which is my house and it's invite only, so it's not really a real shop I just love these trucks and specialize in them, so a upper intake plenum job on a OHV is like one of my favorite pass times......

 

[patoford]

Sure appreciate the information. I will plan on doing all that. Makes it a lot easier having these tips from a pro.
Thanks again!

 

[410Fortune]

I almost forgot you will need a special tool to remove the double sided studs that hold the fuel rail to the lower intake
It is a E7 Torx socket
Do not break those studs, they are hard to get
However if the E7 splined heads do twist, don't fret, you can install them with vise grips

Here is a video that shows how to bench test/clean injectors

 

[patoford]

Thanks again. Got the upper off yesterday. That EGR tube going into the upper plenum was tough but some other forum information helped some in wrestling that off. What is your method on that one? Will tackle the rest today.

 

[410Fortune]

my method is simple, get the upper plenum to clear the intake mounting studs, then twist the rear of the plenum upwards (the whole intake) and it slides right off the EGR tube
OR you can unbolt the whole EGR tube downstream a little bit, two 10mm I think......

When re install, add some vaseline to the big green O ring, clean the inside of the plenum free of debris and it will slide right back on into place