Does intake maifold really need replaced?

[trail-running]

Got the dreaded PO171/174 engine codes. Took it to ford dealer who says it needs intake maifold and valve cover replaced at a mere $1500.00
I have read info on replacing the isolator bolts to fix this but the Ford dealer says the vacuum leak is occuring around the shafts of the Intake Manifold Runner Control plates. They claim that the only way to fix it is to replace the whole intake maifold? Does anybody know any other way to fix this? What a screwed up design this is! The service manager said they have seen alot of these and they thought Ford would step up and take responsibility for the problem but they have not.
It is a 2000 Windstar, 3.8 L Engine.

[phil-l]

I performed the infamous isolator bolt procedure on my 2000 Windstar LX 3.8. It worked out fine; thousands of miles later, the van runs great.

I have a hard time believing there is leakage past the intake manifold runner shafts.

Note that the intake manifold is divided into two parts: The "Upper Intake Manifold" is the black plastic portion (which itself has several pieces). The isolator bolts are what mount this manifold to the "Lower Intake Manifold".

The lower intake manifold is a metal casting (which also contains the EGR ports which are noted for clogging; you can see these pictures in the tremendously useful leckemby.net procedure). This casting also includes the intake manifold butterflies and associated shafts.

I did *NOT* remove the lower intake manifold during my work on the van, and I've not heard of it being a problem in regard to this TSB.

I'd question why they believe the lower intake manifold needs to be replaced. Is there some definitive test that points specifically to the lower intake manifold being a problem? I'd like to know the specifics of such a test (i.e., something that shows the runner shafts are leaking independently of the isolator bolts).

[road_rascal]

This happened about 3 times on my '96. Apparently really small o-rings or seals fail around the shafts that go between the butterfly valves and the IMRC assembly. According to the Ford tech I talked to the only way to fix the problem was to replace the whole lower intake. I had an extended warranty so I really didn't care that Ford was stuck with the bill, but I have a hard time believing that someone hasn't come up with a simple solution to this problem.

[joeuser742]

I also find it hard to believe that the intake manifold needs to be replaced. I know that if you have a gas knock, bad gas mileage, and the codes, then in addition to the isolator bolt TSB, you also need to replace the lower intake gasket. When I first bought my 99, the codes came on and I did the work myself. It was fairly easy and took me about 3 hours, I took my time. Now that I've done it before, I can do it in about 1.5 hours, maybe less.

[Goldlexus]

I had the TSB done almost 2yrs. ago. The ford dealer told my mechanic the same thing. That the lower intake manifold needs to be replaced. It add $500 to the job. According to the Ford dealer they had been doing just what the TSB recommended for their 171/174 code customers. They had started seeing those same customers returning some many, many miles later with the same codes. Since replacing the lower intake manifold they haven't had people coming back. We went ahead and replaced the lower intake manifold being as we had been dealing with the CEL for a couple of years before finding out about the TSB. The final bill with TSB done and manifold was $1000.
We are still dealing with ping issues. Somedays it is worse than others. Our gas milage looks to be around 13 mpg in the city, not sure what the gas milage is on the highway since I don't do much freeway driving. I am beginning to think that we will never be rid of the ping. Our mechanic suggests a fuel injector cleaning but we had done that, got relief from the ping for about a month than it was back.

[joeuser742]

Originally Posted by Goldlexus

I had the TSB done almost 2yrs. ago. The ford dealer told my mechanic the same thing. That the lower intake manifold needs to be replaced. It add $500 to the job. According to the Ford dealer they had been doing just what the TSB recommended for their 171/174 code customers. They had started seeing those same customers returning some many, many miles later with the same codes. Since replacing the lower intake manifold they haven't had people coming back. We went ahead and replaced the lower intake manifold being as we had been dealing with the CEL for a couple of years before finding out about the TSB. The final bill with TSB done and manifold was $1000.
We are still dealing with ping issues. Somedays it is worse than others. Our gas milage looks to be around 13 mpg in the city, not sure what the gas milage is on the highway since I don't do much freeway driving. I am beginning to think that we will never be rid of the ping. Our mechanic suggests a fuel injector cleaning but we had done that, got relief from the ping for about a month than it was back.

Sounds like you still have a vacuum leak somewhere, and/or the EGR ports are clogged again. You should be getting at better MPG than that.

[Goldlexus]

Originally Posted by joeuser742

Sounds like you still have a vacuum leak somewhere, and/or the EGR ports are clogged again. You should be getting at better MPG than that.

Well the intake manifold is fairly new so I doubt EGR ports are clogged. Even in the old lower intake manifold the egr ports looked pretty good. I saw the manifold after it was pulled. Wouldn't I be getting a CEL light if there is a vac. leak somewhere?

[wiswind]

Trail-running, I would see if the TSB for the isolator bolts has been done.
If not, I would have that done.
Yes, I have read posts about problems with the lower intake manifold regarding the IMRC shafts....and others have indicated the same here.
Point being, if the TSB has NOT been done on the upper (isolator bolts), then that is most likely your problem.

Lower intake manifold gaskets MUST be replaced whenever the lower intake manifold is removed.... They are NOT re-usable in any way.
Not to be confused with the upper intake manifold gaskets, which go in between the upper and lower intake manifold.
The bolts for the lower intake manifold ARE re-usable.
I would recommend replacement gaskets for the lower intake manifold be bought from FORD only, as they have made improvements to them, that are not available in the aftermarket. The cost is very cheap, even at dealer list prices (about 50-60 dollars) which is very cheap as compared to the labor cost involved in the replacement.
The lower intake manifold gaskets go in between the lower intake manifold and the heads. Coolant flows through there. When removing the lower intake manifold, a lot of coolant will run into the crank case (into the oil), so a oil change is a MUST before running the engine.