Quote:
Originally posted by bad30th
if the melting point of the plastic used is far enough above the actual temperatures reached, then it is actually a good idea. Weight savings, heat transfer, ability to injection mold, etc.
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Well I can assure you that THIS plastic is JUNK. It can not handle what it is supposed to do and will crack over time. In my case, the intake maniold cracked and i had to replace the entire engine after 65,000 miles.
Replacing engines due to cracked intake manifolds does not come under the heading of normal maintenance.
Here's a link that shows the problem.....
http://www.babcox.com/editorial/ar/eb110112.htm
Here's a link to consumer affairs....
http://www.consumeraffairs.com/automan/plastic.html
Here's a link to the news that the National Highway Traffic Safety Administration is investigating the plastic intake manifolds for exploding under backfire and causing engine fires....
http://www.pulse24.com/News_Features...5-001/page.asp
As far as "weight savings" goes, a typical plastic intake manifold weighs 4.5 kilograms, verses 12.7 kilograms for aluminum. Over the lifetime of the car, this weight savings will save the automobile owner $7.91 in gasoline. Roughly a Big Mac Combo and a Sundae at McDonalds. Of course, the new engine you will need to buy will run you in the area of $5,000.00, but hey, you did get that Big Mac Combo and Sundae for free!
I am sure you want back up, so please click on this link the EPA in the USA who did an extensive study comparing aluminum and plastic intake manifolds. Pan down to page 24 at the bottom of the page so you see i am not pulling these numbers.
Another interesting tib bit in this EPA report is on page 18 where they grade the manifolds. Read the structural marks.
http://www.epa.gov/ORD/NRMRL/Pubs/60...A600R99023.pdf
Here's a guy who almost got scortched...
http://www.cartrackers.com/Forums/li...Lemon/395.html
GM has a very big problem on their hands.
There are millions of these pieces of junk engines on the market (all 3800 type K built between 96 and 2003) In 2004 supposedly they have altered the design.
THE ONLY REASON THAT GM IS USING PLASTIC INTAKE MANIFOLDS IS THAT THEY ARE CHEAP CHEAP CHEAP TO BUILD. Again refering to the EPA study, page 18, you will note that plastic intake manifolds cost half of what an aluminum manifold costs.
If when i bought my buick they said to me, "Hey, you can have the car for X and get a cheap plastic intake manifold that will crack and destroy your engine at 65,000 miles costing you $5,000 hard earned dollars, or pay $100.00 more and get an aluminum intake manifold that will last forever"
Wonder what I would have done?