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Does GM use plastic intakes on there new cars? :huh:
 

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i think so, at least with the LS-series engines. :confused:
 

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Originally posted by karhopper@Mar 21 2004, 05:51 AM
Does GM use plastic intakes on there new cars? :huh:
all Gen III motors have a plastic resin intake, yes.
The Gen IV also have plastic intakes.
 

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Originally posted by Rabbit@Mar 21 2004, 04:51 AM
I've seen a fouled one of these. I hope they got the bugs worked out on the newer ones.
I don't see how one could have fouled. There is not coolant running through them, so it's not like anything inside of them is under pressure. The only thing I could see is someone making smacking a wrech or something off of one of the runners or something and then cracking it.

Ford's modular motors also use the composite intake, but they do have coolant running through them. Some of their earlier designs had problems cracking (such as my buddy with a 96 GT). I'm not sure when they switched, but the newer style has a cast section that's under pressure so it's not going to leak.

If you are worrying about the life of the "plastic" intake, don't.
 

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Originally posted by Rabbit@Mar 21 2004, 09:51 AM
I've seen a fouled one of these. I hope they got the bugs worked out on the newer ones.
fouled? I have heard of some problems with the gen III motors, but nothing to do with the Intake.

Only down part is that it cant be ported like an aluminum or other metal intakes. Dont get too worked up about it, nothing all that important.
 

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I don't know what happened, but my mechanic showed it to me and one of the paths was melted to the point of clogging.
 

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Originally posted by Rabbit@Mar 22 2004, 10:07 AM
I don't know what happened, but my mechanic showed it to me and one of the paths was melted to the point of clogging.
Melted eh? Man, they have more problems then a plastic intake to worry about.
 

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3.8L Series II have had some problems with catching fire when starting, The engine will back fire and the intake melts causing a under hood fire. I have seen this at the dealership that I worked at, a 1997 Olds 88
 

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GM has used plastic intakes for 10 years. Ford and Chysler use in on almost all their models. A lot of Foreign cars use them too. A few have had limited problems, but most if not all were production problems not design.

Engines that use plastic intakes:

GM
96+Vortec V8s
94+ GM 3800 (not series III or supercharged engines)
Northstar
3500 DOHC

Chryslers:
00?+ 3.3, 3.8
2.4
2.7,3.2,3.5
Hemi

Ford:
3.0
3.0 DOHC
4.0 SOHC

And lots more.

-T
 

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Plastic intakes have the advantages of giving a smooth surface to the ports and airways which decreases any turbulence. But the main advantage is that they cost less and are lighter.
I have heard that GM has had problems with these intakes particularly sealing. In fact, some motors will exhibit hydrostatic lock due to coolant loss into the cylinders.
Motor Magazine may have been the source.
The other possible problem related to sealing is torquing the screws to obtain a seal without cracking the unit. Hopefully, the part has been designed with this in mind.
My apprehension is that parts are now being designed with the warranty in mind. What happens to those customers that keep a vehicle for 5+ years-into the 100,000 mile range? Everybody applauds some gadget that performs well on a new car but will it hold up to fatigue induced by vibration and temperature variations?
 

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Originally posted by 69nova@Mar 22 2004, 01:33 PM
I have heard that GM has had problems with these intakes particularly sealing. In fact, some motors will exhibit hydrostatic lock due to coolant loss into the cylinders.
Motor Magazine may have been the source.
As I mentioned above, the Gen III do not have coolant flowing through them - just air.
 

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Not everyone is referring to the LS1.
Basically, I have learnt to refer to the plastic upper intakes as
"expensive, cheap intake gaskets"
because that is basically what they are.
The major problem is with warpage, just think of the warpage difference
between steel and aluminum, and double it to see the difference between plastic and aluminum. Which is sad, because there are composites out there that could do a much better job, but aren't being used.
 

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Ford's had problems with them as well:

: This article was taken from www.canadiandriver.com

May 2, 2003

Secret warranties "unfair": Lemonaid author


Toronto - Consumer advocate and author of the Lemon-Aid Used Car and Minivan Guide 2004, Phil Edmonston, says that many General Motors and Ford models built from 1995 to 2001 have serious engine intake manifold defects which the automakers sometimes cover with secret warranties rather than admitting their mistake and recalling the millions of cars and vans involved.

Edmonston points out that the Internet is full of protest websites set up by angry car owners who've had to pay $1,000-$3,000 for repairs that other motorists get for free. Sites like GM V6 Lemons and Big Class Action show all owners should be compensated for what is essentially a factory defect.

"Secret warranties provide for free repairs long after the original warranty has expired. Engine intake manifolds usually fail around the 100,000 km mark and automakers have quietly issued service bulletins to dealers that describe the problem and suggest ways to correct the problem. Auto manufacturers aren't required to notify owners of the defect."

Edmonston says the Ford engine problem is caused by inherently defective 4.6L engine intake manifolds. These manifolds are manufactured out of plastic and have an abnormal tendency to crack, leading to overheating and in many cases complete engine failure and/or damage to other parts of the car's engine.

Ford has offered to replace these defective intake manifolds free or charge for cars purchased by police forces and taxi cab companies. However, says Edmonston, Ford has yet to offer such a "recall" to individual consumers who purchased the same cars.

The following models equipped with Ford's 4L, V8 engine may have defective engine manifolds:

: Mercury Grand Marquis (1996-2001);
: Ford Mustang (1996-2001);
: Ford Explorer (1996-2001);
: Ford Crown Victoria (1996-2001);
: Lincoln Town Car (1996-2001);
: Mercury Cougar (1996-1997);
: Ford Thunderbird (1996-1997),
: and all Mercury Grand Marquis (1996-2001).
Edmonston also says that intake gasket failures are a chronic problem with General Motors 3.1L, 3.4L, and 3.8L V6 engines produced from roughly 1995 through 2001, as well as the V8 used in SUVs and trucks. GM's Venture and Montana minivans are particularly prone to having these failures.

Edmonston says a poorly designed plastic intake manifold gasket that is leak-prone allows Dex-Cool (orange) antifreeze to leak into the engine, causing the failure.

Edmonston recommends that owners with defective engine intake manifolds, not covered by the original warranty, should ask their service manager to make a "goodwill" or emissions warranty application to GM or Ford. If no refund is offered, consumers should have the repair done at an independent garage and use that garage's report as proof in small claims court.
 

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What is the fix for these cases?
Except for a re-designed part, you are looking at recurring problems.

How I hate the methods of weight saving. In contrast, on my all cast iron Pontiac motor (400 cubes for my 73 Grand Prix), I had a hose blow while on the highway and before you knew it, the motor just ground to a halt. I let it cool, walked to a service station for a new hose and coolant and replaced the hose. Started it up and ran the car for another 5 years with no problems until I sold it. If you want to save weight, make the seats lighter.
And the transmission on that 73 was a real rock crusher.
An aluminum intake manifold would suit quite nicely.
 

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Like I said it's not the parts design that usually at fault. It's simply a bad run. It's really a quality control thing. If the part is made correctly they do work. The fix is to get a new part from a different batch.

-T
 
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