28
votes
Why do cars have plastic shrouds over the engine?
Mostly the point is, to make it "look good".
There is arguably some protection for wires and pipes underneath against animals chewing on them, depending on how its implemented.
Also, on some models ...
- 1,082
18
votes
Accepted
Why do cars have plastic shrouds over the engine?
The cover is not purely cosmetic and serves several purposes, one is to reduce engine noise. You often notice there's foam on the inside and they fit over components such as cams and injectors.
A ...
- 644
18
votes
Car imitates dead battery but comes back to life ~30 minutes later and lets me start it
Since you lost power to your 12v accessory socket at the same time as the other systems, I can’t see this as being an computer malfunction. This sounds to me like you have a fault in your main fuse ...
- 25.5k
18
votes
Car stalls when coming to a stop except when in neutral
Jupiter's answer is well-founded and I've upvoted it, but you might consider one more possibility: that your lockup torque converter is failing to unlock.
If this is happening, you might feel a lurch ...
- 8,518
18
votes
Why do many CVT cars appear to index gears during normal automatic operation?
It's due to the hatred of CVTs by car reviewers. If you create a technically excellent car, something that achieves great engine lifetime, low fuel consumption, etc. by having a CVT that always runs ...
- 15.3k
17
votes
Is it absolutely necessary to replace all four tyres on a manual 2008 Subaru Impreza?
Driving around with tires of different rolling radii will cause the viscous coupling to get hot / overheat and eventually fail...
As it will probably happen long enough after the tire fitter did the ...
- 34.7k
17
votes
Accepted
Why do many CVT cars appear to index gears during normal automatic operation?
In addition to the "perception" issues mentioned in the other answers, there is a real engineering reason for the stepped-ratio behavior of a CVT, especially under hard acceleration.
The ECU ...
- 332
14
votes
Accepted
Why is a 12V outlet that provides 120W protected by a 20A fuse in my 2015 Forester?
The purpose of the fuse is to limit the current in the wire to prevent it from overheating. That could cause the insulation to melt or even start a fire. The other components in the circuit will (...
- 14.5k
12
votes
Why do cars have plastic shrouds over the engine?
The other function can be to control cooling airflow, so yes, get them to put it back - even if they have to buy one...
- 34.7k
11
votes
Why is a 12V outlet that provides 120W protected by a 20A fuse in my 2015 Forester?
The fuse is for the entire circuit. There may be other things on that circuit, sharing that 20A fuse.
Also, the gauge of wires used in a circuit is part of the "safe" current limits (maybe why your ...
- 12.2k
11
votes
Accepted
Is it worth replacing the entire clutch assembly when the clutch release bearing fails?
At ~110k on the clock it's quite likely that it's the original clutch, and if so you're going to be significantly closer to the end of the clutch's life than the start.
Given the big labor cost/...
- 10.5k
10
votes
Accepted
Car imitates dead battery but comes back to life ~30 minutes later and lets me start it
You may have a loose or corroded engine ground connection. The next time you have the electrical failure, leave the ignition switch ON and, using a voltmeter, measure voltage between the negative post ...
- 8,518
9
votes
Car stalls when coming to a stop except when in neutral
Two things come to my mind:
First would be a bad idle air control valve and\or dirty throttle body. The IAC valve may turn on the check engine light.
Second would be a significant missfire which ...
- 3,440
8
votes
Accepted
2007 Subaru Outback 'Leak' ... what is it?
The oil seen is from the block to cylinder head gasket seam. This is a nearly universal problem on Subaru 4 cylinder engines from the late 1990s well into the 2000's. The average mileage that this is ...
- 11.7k
8
votes
Accepted
Torquing Strut Nut with Tire on Ground
You should leave them just about snug, if not just a little loose. If you tighten them before you put it on the ground, when you do get the car on the ground, there will be tension on the parts, which ...
- 162k
7
votes
air pressure in low profile tires
You don't have to regularly put air in low profile tires. Have the tires checked to see if there's a problem - an ill-fitting bead or a nail.
- 8,722
7
votes
air pressure in low profile tires
Low profile tires tend to be installed on nicer alloy type wheels. Fancy alloy wheels are highly susceptible to sealing issues as it's easy for them to become damaged and have corrosion form causing ...
- 12.5k
7
votes
Accepted
High-mileage transmission with no known oil changes. Safe to change fluid now?
If this were my vehicle, I would change the transmission fluid and filter. There is a baseless school of thought, more like an "old wives tale" that you will just cause damage by changing ...
- 12.1k
7
votes
Why do many CVT cars appear to index gears during normal automatic operation?
If the Toyotas you've driven were relatively recent (2018 and later for the Rav4, 2019 and later for the Corolla), they use the Toyota K120 CVT transmission, which is marketed as "Direct Shift&...
- 171
6
votes
Accepted
Small black box located under intake manifold
It's a vacuum canister, it holds vacuum so the EGR can operate smoothly.
Video of a guy talking us through the Subie's intake on his workbench
Video of the same guy talking us through the Subie's ...
- 12.2k
6
votes
Accepted
Are exploding axles common?
No, exploding axles are not a normal thing. Return to the shop that replaced them, there should be a warranty on them. Either:
the axles were defective
the axles weren't installed properly
the axles ...
- 12.2k
6
votes
Accepted
What is this white component on the upper air intake plenum? Thanks
It the PCV Diagnosis Connector (E51). It routes to D12 on the ECU, and the other side is grounded.
It's a sensor of sorts, not a solenoid or valve. It's really nothing but a mechanical "switch" ...
- 12.4k
6
votes
Is it absolutely necessary to replace all four tyres on a manual 2008 Subaru Impreza?
It is possible to get new tires shaved down to the same tread depth as the existing worn ones. It may be worth getting that done, then you wont have to replace them all.
For example this article says ...
- 25.5k
6
votes
Is it absolutely necessary to replace all four tyres on a manual 2008 Subaru Impreza?
Subaru's have lots of quirks, and tire size is one of them. Talk to a Subaru mechanic rather than a tire-changer, and you'll get a completely different answer.
Subaru's are well known for having ...
- 8,722
6
votes
Why do cars have plastic shrouds over the engine?
On petrol engines the cover can help protect against water accumulating on top of the engine and interfering with the coil packs/ignition.
Rain/condensation can get into the engine bay and over time ...
- 171
6
votes
Occasional hard start possible causes?
The fuel pump has a check valve inside to retain fuel rail pressure. If that valve fails, you have to crank the engine for around 5-10 seconds to refill the fuel line and rebuild pressure. You can ...
- 1,392
5
votes
Overheating Subaru
Subaru Thermostats are different from those you buy at OReilly and other auto stores. You NEED to buy the OEM thermostat from Subaru; the design is different.
Before bothering with the thermostat, ...
- 8,722
5
votes
Accepted
Subaru Forester power window stuck
Do you have a test probe? If so, check that the buttons are sending a current to the motor's relays. If you've left it in one position, it might be a good idea to use a silicon spray into all the ...
- 644
5
votes
Audio System Noise-supercharger whine
This has less to do with the audio signal, than it does with grounding. What you have described is a ground loop.
You likely have a grounding issue somewhere. Obviously we are not able to tell you ...
- 9,005
Only top scored, non community-wiki answers of a minimum length are eligible