Absolutely none of those parts being made out of "metal" will contribute to longevity.
Utter nonsense. I've seen failures of all the listed (and other) plastic parts that would not happen with metal (aluminum, steel). Example1: I owned a BMW. Plastic thermostat cracked. Example2: Brother's Honda plastic valve cover warped. On my 3 cars (20+ year old), all the listed parts are made from various metals and all are original.
Thank you for sticking to the topic! I suspected so but wanted to ask just in case there was still a unicorn out there.
I know a lot of metal oil pans and gas tanks have been replaced due too rust. I’ve never heard of a plastic fuel tank having issues.
Rust/corrosion is a non-issue here in TX but heat certainly is. Plastic tanks are OK, I didn't list that as an item.
Intake - no way they could build the complexity of modern intakes into a cast piece. If there done right they don't cause issues
Valve covers - the injection molded ones incorporate the spark plug tube seals directly. Again, would be very expensive to do with stamped steel, and likely wouldn't be as good.
Thermostat - this one I agree with you, but given most OEM's now incorporate a sensor directly into the housing, I think this is here to stay.
Oil filter - the new Toyota Dynamic force 4 cylinders have a traditional can type oil filter screw on mount on the bottom of the engine - so this is still available.
Oil pan - I 100% agree with this. Many cars still have this - again my Toyota does. For some vehicles an aftermarket replacement option is available if they come with plastic. Some are easy to change. Some not so much.
The Toyota 2ZZ-GE engine in my two Vibe GTs is plenty complicated and the intake is all aluminum. It can be done. Valve cover also aluminum. Will last forever. Agree with the rest!
I don't understand the whole issue with plastic cover or parts that only see air. plastic intakes, valve covers and even oil/transmission pans. they have been used for a while now, and with some exceptions its relatively successful.
The main issue is heat cycling and tendency of plastics to degrade with time, not chemical breakdown due to contact with fluids. That said, none of the parts listed "only see air." All see oil and/or fuel due to their location, EGR and EVAP systems.
You happen to pick five components out of what, 10,000, and think that you’ve got a measurable difference in longevity?
Of said components, absolutely!
Those aren’t very high failure rate components. What about the rust proofing on the vehicle? what about the driveline longevity? What about those engines that have machining debris in them?
Yes they are. There are many other things to consider, of course, but that's not what this post is about. This post is specifically about use of plastic/metal in those components.
Further, even if the .001% of the car’s components on which you are focused are made of plastic, why do you think they don’t last?
Personal experience. Plastic warps and/or crack with age and use due to heat cycling. I've seen all these components fail when made of plastic on various cars (obviously not all at once) but rarely/never when they're metal.
My wife’s Volvo has over 300,000 miles on it. It has a composite (plastic) oil filter housing. That housing has been off and back on over 50 times, roughly speaking.
Cool, so you're the 1, congrats on winning the lottery. Anecdotal and lucky. All the listed components in all 3 of my current cars are made from metal and all are original with zero failures.
