Plastic outer engine parts

[rationull]

So it seems like there's a trend going with newer cars where external engine parts that used to be metal are now plastic (of course that seems to be the trend with lots of things). I'm not passing judgment on this since I'm sure the various manufacturers have their reasons (cost, weight?) and hopefully they're not sacrificing too much durability of longevity.

I just wanted to chime in about what's plastic/composite on my 07 civic and see what other cars share the same "design decisions." I've got:

- Intake manifold (seems like this is getting pretty common)
- Engine oil dipstick
- Valve cover

In particular I hope the plastic dipstick doesn't break off at some point from too many heat cycles.

 

[GMFan]

My parent's 1999 Volkswagen Jetta has a plastic dipstick tube. It gets brittle and has broken 3x since we've had the car. It has 103k miles on it.

They like it though, because they make $11 on every new one we have to buy.

 

[drewjp]

The actual dipstick that goes into the hot oil is plastic? Geez that is penny pinching.

My intake manifold and valve cover are both plastic also. It also seems that the automakers like to cover up the engine bay in sheets and sheets of 'decorative' plastic, more common in luxury cars, but still.

I for one still appreciate being able to see my engine when I open the hood.

 

[rationull]

The civic fortunately doesn't have any plastic engine covers beyond a small piece that covers all the wires going to the ignition coils (on top of the plugs). Although I guess the valve cover is technically a "plastic engine cover" on its own

And yes, the dipstick is plastic. Bring orange plastic. It's nearly impossible to read the level on it when the oil is new and clean. I've got it in the back of my mind to keep looking in case a metal aftermarket dipstick becomes available at some point.

 

[dwendt44]

If a particular engine has been around for some years, perhaps one of the earliest model years has a metal dip stick tube that can be fitted to the newer engine.
Just a thought.

 

[rationull]

Good thought. This engine was new for the 06 civic though. Don't think there were ever metal dipsticks for it.

 

[Colt45ws]

My 4.6L has plastic valve covers I believe. Ive never heard of them breaking. I dont see any reason for them to either. It also has a plastic intake manifold. I know the 96-01ish 4.6L had a plastic I/M with a plastic coolant crossover. I have heard of that crossover breaking. They have since been updated with a aluminium coolant passage. The only reason I have seen for the plastic intake manifolds breaking otherwise are wet nitrous backfires...

 

[blackcherry06]

None of the plastic bits worried me until I bought a car that uses a plastic oil filter housing...such as the one on the Mazda 2.3 I4. It uses a cartridge-type filter and is contained in a plastic cup, screwed into the bottom of the engine. One wrong move while removing / installing it can result in a crack, and eventual oil loss. The parts guy at my local Mazda dealer said all the failures they've seen were a result of people using pump pliers and the like to remove / install them. Lord help us all. It won't surprise me at all to see an eventual recall for a metal replacement. Since heat and age seems to have detrimental effects on plastics, it seems like they'd all eventually fail through no fault of the owner.

 

[Max_Wander]

Originally Posted By: blackcherry06
None of the plastic bits worried me until I bought a car that uses a plastic oil filter housing...such as the one on the Mazda 2.3 I4. It uses a cartridge-type filter and is contained in a plastic cup, screwed into the bottom of the engine. One wrong move while removing / installing it can result in a crack, and eventual oil loss. The parts guy at my local Mazda dealer said all the failures they've seen were a result of people using pump pliers and the like to remove / install them. Lord help us all. It won't surprise me at all to see an eventual recall for a metal replacement. Since heat and age seems to have detrimental effects on plastics, it seems like they'd all eventually fail through no fault of the owner.

If you're that worried, or will eventually have to take the car to a quickie lube screwup emporium, then you might wanna convert to a spin-on canister type (from the 2.0L). The marginal cost is a good investment imo.

 

[The_Jeff]

Originally Posted By: blackcherry06
Since heat and age seems to have detrimental effects on plastics, it seems like they'd all eventually fail through no fault of the owner.


Absolutely. Try unplugging any wiring harness on any 15 year old car... there is no flexibility left in the plastic so it just snaps...

 

[Duffman77]

Platic Intake manifold and valve covers would be a good thing. Platic intakes keep the intake charge cool and save weight. The valve covers save weight as well and probably transmit less noise.

 

[CivicFan]

Originally Posted By: drewjp
... It also seems that the automakers like to cover up the engine bay in sheets and sheets of 'decorative' plastic, more common in luxury cars, but still.
...


It's for noise insulation.

 

[blackcherry06]

Originally Posted By: Max_Wander

If you're that worried, or will eventually have to take the car to a quickie lube screwup emporium, then you might wanna convert to a spin-on canister type (from the 2.0L). The marginal cost is a good investment imo.


I do all my own oil changes and keep an extra housing on hand. I don't feel I can trust a Jiffy Luber with a car with a conventional filter, I'm sure not about to trust them with the Mazda.

 

[Eddie]

I hear you as my Mazda CX7 has the canister cartridge. I bought ($4.5) a cap type oil filter wrench that fit on the thermo plastic cover. I don't expect any problems as long as I do it myself. Jiffy Lub--I THINK NOT.