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Are the valve covers on Honda Pilots made of plastic. I discovered an oil leak on my Pilot and had my mechanic check it out. He called me and told me that the leak was coming from the valve cover and gasket. The valve cover had a crack in it and it is made of plastic. I have never paid attention to this before. I think that my last honda had aluminum covers. If they are plastic, I figure that it was a weithg saving measure.
 

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My 2005 has Aluminum covers. I can’t imagine them being plastic
 

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Are the valve covers on Honda Pilots made of plastic. I discovered an oil leak on my Pilot and had my mechanic check it out. He called me and told me that the leak was coming from the valve cover and gasket. The valve cover had a crack in it and it is made of plastic. I have never paid attention to this before. I think that my last honda had aluminum covers. If they are plastic, I figure that it was a weithg saving measure.
The 1st and 2nd generation Pilots are metal. The 3rd gen maybe plastic. Most new cars are plastic these days.
 
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It's mostly a nonissue so I don't get the anxiety. Plastic has better thermal and corrosion properties for such applications. Intake manifolds, valve covers, timing covers - there are plenty of areas where the appropriate grade of plastic can perform the duties just fine. The issue is every once in a while when a manufacturer selects the wrong type or they have a bad batch from a supplier and it causes issues.
 

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It's mostly a nonissue so I don't get the anxiety. Plastic has better thermal and corrosion properties for such applications. Intake manifolds, valve covers, timing covers - there are plenty of areas where the appropriate grade of plastic can perform the duties just fine. The issue is every once in a while when a manufacturer selects the wrong type or they have a bad batch from a supplier and it causes issues.
Plastic is fantastic: light-weight, strong, rust-free and can be molded into the optimum shape but since I tend to keep my vehicles for a long time (not like your Chevy) there is a concern for cracking from age or from overzealous tightening. But at least some JB weld might seal a crack ….:p
 

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Plastic is fantastic: light-weight, strong, rust-free and can be molded into the optimum shape but since I tend to keep my vehicles for a long time (not like your Chevy) there is a concern for cracking from age or from overzealous tightening. But at least some JB weld might seal a crack ….:p
Which Chevy - I expect I'll have the '61 Impala longer than you own any car... ever. And I keep it away from DE to stay away from that salty oceanfront air!

Cracking and/or warping are some concerns of time, but most plastic parts can be easily replaced so I'm still OK with it when strategically used. Not that I want to go replacing parts just because they cracked or warped but if it helps keep the costs down (vehicles are expensive enough) and helps lighten the vehicle since more computers and weight seem to be added with each generation.
 
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Yeah the plastic intakes seem pretty solid... valve covers for sure seem more prone to cracking and leaks. I'm not opposed to it especially given that soon we'll probably just be 3d printing the replacements when we need them at home. :)
 

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Discussion Starter · #11 ·
Are the valve covers on Honda Pilots made of plastic. I discovered an oil leak on my Pilot and had my mechanic check it out. He called me and told me that the leak was coming from the valve cover and gasket. The valve cover had a crack in it and it is made of plastic. I have never paid attention to this before. I think that my last honda had aluminum covers. If they are plastic, I figure that it was a weithg saving measure.
Plastic is fantastic: light-weight, strong, rust-free and can be molded into the optimum shape but since I tend to keep my vehicles for a long time (not like your Chevy) there is a concern for cracking from age or from overzealous tightening. But at least some JB weld might seal a crack ….:p
It's mostly a nonissue so I don't get the anxiety. Plastic has better thermal and corrosion properties for such applications. Intake manifolds, valve covers, timing covers - there are plenty of areas where the appropriate grade of plastic can perform the duties just fine. The issue is every once in a while when a manufacturer selects the wrong type or they have a bad batch from a supplier and it causes issues.
The fact that they are plastic does not bother me. Its just that I did not know they were plastic. I am however going to scout around to see if I can come across aluminum ones and replace them . My Pilot has 206000 miles on it and it runs great so I want to keep it as good a possible. Im going to run her till the doors fall off. The body is in excellent shape and the engine runs great. If I have any transmission problems, Im going to have her fixed and just keep on keeping on. I have all the engine and tranny service done regularly and anything else that needs done Im am on it right away.
 

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The fact that they are plastic does not bother me. Its just that I did not know they were plastic. I am however going to scout around to see if I can come across aluminum ones and replace them
I'd leave the plastic valve covers alone. Maybe it could be considered when the next valve adjustment comes due.
 

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I think his mechanic said one was cracked- do you just JB Weld or do you replace?
 

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I'd leave the plastic valve covers alone. Maybe it could be considered when the next valve adjustment comes due.
Agreed with Aggrex on this one.


There are a lot of things specific these days about valve covers, things that connect to them, and converting them would be more hassle than it’s worth. Remember too that the 3rd gen is a direct injection engine…. Aka I’m 99.99999 sure the earlier metal ones have no hope of fitting the newer DI head. If they’re cracked call Honda and get some new ones. That’s the best answer here.
 

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I think his mechanic said one was cracked- do you just JB Weld or do you replace?
Forgot that part of the story as the focus went to plastic vs metal engine parts. Replacing the cracked plastic cover with the correct part makes sense especially with an oil leak. JB could be a decent McGuyver move for an emergency repair.
 

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Plastic is fantastic: light-weight, strong, rust-free and can be molded into the optimum shape but since I tend to keep my vehicles for a long time (not like your Chevy) there is a concern for cracking from age or from overzealous tightening. But at least some JB weld might seal a crack ….:p
Plastic is cheaper, but inferior. Fundamentally a valve cover's job is to seal the engine. To do this, you need bolt clamping force that does not change with time and distributes the pressure evenly. While plastic an be strong (resistant to breaking) it is not stiff. Plastic, even reinforced plastic valve covers are almost 10X more flexible than are aluminum. Thats why the gaskets leak.

Astrobuf PE
 
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