I love my Subaru Impreza, but it is giving me frequent headaches

Dear Baraza,

Thanks for the advice you gave me when I was contemplating choosing between the Subaru Impreza and the Toyota Auris. I am now a happy 2008 Impreza owner for slightly over a year. Lately however, the car has been showing some queer behaviour. When I get to an incline after a long distance (say 180km) the car threatens to overheat. I say threatens because it will blink ‘hot’, but on stopping, the warning will disappear even before I step out of the car. The car can then proceed with the hill and the rest of the journey as long as I don't push it very hard. And if I do, the warning returns and only disappears when I go back to around 2500 rpm. It’s a digital gauge, I should add, and runs okay for months until I request it to take me upcountry.

The coolant will be high in the reservoir when this happens. There was a time it would pop open the reservoir lid, but the issue was solved by changing the radiator cap. All the mechanics I’ve consulted have given various suggestions, including removing of thermostat at the first mention of the word overheating. What do you think I’m dealing with here? The radiator, heat sensor, thermostat and gaskets have all been mentioned.

Regards,

Ken

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Hi Ken,

I’m glad you are a happy owner of something I recommended. Now, allow me to point out one or two things you may be doing wrong:

If the cooling system pops open the reservoir lid, then you have made one very obvious error: you overfilled the vehicle with coolant. I don’t know about the exact engine design you have despite it being a 2008 Subaru, but in my own car of the same brand, but seven years older, the expansion tank has an overflow nozzle for just such a scenario. Once the coolant follows basic physics to a critical level, the surplus exits stage left — literally to the left via the left-facing nozzle — up and out of the cooling system.

I’d have thought your car would have this feature as well. It seems it doesn’t, or if it did, this nozzle has been blocked off, which is another very wrong thing to do. Coolant system pressures can rise to uncomfortable levels especially when the dissolved gases are heated enough to not only divest their dissolution status, but to gain pressure as a bonus.

That’s why it’s unwise to open any inlets/outlets of the cooling system in an overheating engine: the hot pressurised gases carry along with them a good amount of even hotter coolant and will enter the atmosphere as a searing geyser that can cause grievous bodily harm to bystanders.

As you can see, you didn’t need to change the radiator cap, but on the upside, you can count this as preventative maintenance, especially if the original was plastic and the replacement is metallic (like I said, I may know engines but certain details belong to the arcane).

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The good thing is you did not fall into the thermostat-ectomy trap that a lot of people lay for others and even more people fall into. Now we get to the bad news:

You may be looking at some form of failure or malfunction, all possible suspects of which portend a looming mechanical catastrophe.

The high coolant pressures suggest either a blockage in the cooling system or a leaking head gasket. It’s fairly easy to tell if the cooling system is blocked.

The first method is to literally risk life and limb by touching one of the hoses when the engine gets more than warm.

You should be able to feel the coolant flowing through the pipe. If you cannot, then either there is a blockage or the water pump is not working.

Touch those pipes to your own detriment, though. Once hot enough they can cause a nasty burn.

Another way of detecting a blockage is to open the radiator cover — usually offshore of the radiator itself in some engines like mine, but always at the top of the engine — then open the drainage plug at the bottom of the radiator. Plug in a hose pipe at either of the two openings and start running water through it.

If the water is pushed out of the other hole, then there is no blockage. If the water is pushed back out the same opening you fed the hose pipe into, there lies your problem.

For the head gasket, there are a few ways of telling whether they’re leaking or not. One is a compression test, which you will need garage equipment for, so I won’t bother going into the details thereof.

The other is to run the engine with the radiator cover open and the coolant filled to the brim. Rev the engine. If the coolant bubbles shortly after every time you rev, then that is suspicious. Check the coolant. An oily film at the top also suggests imminent gasket failure and of course the worst case scenario is what people call mixing oil and water: the coolant either looks like milk tea or has light brown chunks in it that are oily to the touch.

There are two more possible causes that will require an electrician to confirm: either the thermostat is stuck, which would cause the water pump and the fans not to activate, or the water pump and/or fans are not activating anyway.

Please note these are two different things: the first means the thermostat is malfunctioning while the second means the water pump and/or the fans are malfunctioning. The first can cause symptoms similar to the second, so get this right.

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How does Subaru really fair after a few years of use?

Dear Baraza,

I have been seeing complaints on social media about the Subaru and the mechanical problems it ostensibly develops after some years of use. One of the problems mentioned has to do with the CVT transmission. Is this the case? Also do a comparison between CVT, automatic and manual transmissions. I need to particularly understand how the CVT works. Another mentioned problem is head gasket damage. Are these Subaru-only problems or are they universal problem?

Thiga Muraya.

Hi Thiga,

Yes, you are right about Subaru and its god-awful CVTs. I don't rag on those whirring little annoyances for nothing, it turns out they're actually junk. I'm referring to the transmissions, not the cars themselves. T

he cars are awesome. Subaru has a CVT they call Lineartronic, which is boring despite their attempts to sex it up by introducing virtual shift points to make them mimic the behaviour of a regular automatic a bit more convincingly. Few fell for that ruse, and that is where the rain started beating them.

They made a big deal about their CVT design boasting two hydraulically controlled pulleys connected by a metal chain, metal because 1. it eliminates the whirring annoyance I mentioned earlier (called CVT whine) and 2. metal is hard so it will last forever, so long that they could label their Lineartronic whatchamacallit "maintenance-free". Hubris rarely bears sweet fruit. Subaru's hubris bore fruit as bitter to the taste as maintenance-free CVT fluid that needs changing.

 [Public Service Announcement: Don't taste CVT fluid, expired or not, it will make your tongue coil back on itself and shred your intestines into little chunks the size of indicator stalks.]

It turns out maintenance-free in Subaru's case literally translated to "free from maintenance" which never bodes well for anything mechanical. Borrowing a leaf straight from "The Land Rover Warranty Handbook & Guide For Car Manufacturers Who Want To Stiff Their Buyers", Subaru's CVTs started acting the fool the day the warranty expired, exactly like Land Rovers do with everything else.

Shaking, shuddering, hesitating, stalling, knocking, jerking and other histrionics violent enough to make drivers think they had been rear-ended became the order of the day and swarmed Subaru's suggestion box to the point they screamed "ENOUGH!" and came one step away from issuing a total recall. You know what one step from a recall involves? It involves a TSB.

A TSB is a technical service bulletin, and it can be carried out in several ways. One is the Land Rover method of keeping quiet about the whole thing and asking dealers to surreptitiously use a knife to cut holes into the dashboard and upholstery of the Freelander 1 where they forgot to put AC vents at the factory*. If the client sees the knife and asks what it is for, quickly toss the offending cutlery under the car, stare at them blankly and ask "What knife?". All TSB repairs are done in secret during regular service programs.

[*This is not an exaggeration, it actually happened]

The other method is to be honest and open enough to tell your customers to head to the nearest dealer for rectification at their earliest convenience and at a heavily subsidised fee (sometimes at no charge at all). This is the path Subaru chose and the extent of their service bulletins ranged from severe jerking (TSB 16-90-13R) to leaking fluids from failed gaskets in the CVT's oil pump chain covers (TSB 16-103-16R) to failing oil pressure sensors (TSB 16-102-16) to more jerking at idle, the kind where folks thought they had been rear-ended (TSB 16-104-17).

The affected vehicles were the Impreza, the Legacy, the Forester, the Outback and something called the Crosstrek. You may notice that this list of Subarus can be summarised into only three words: ALL OF THEM. Get a grip, Fuji!

Fuji did get a grip and even did one better: they extended the warranties on some of these vehicles, about 1.5 million of them, made between 2012 and 2017, or "ripe for importation into Kenya" in other words.

Some activist voices called the warranty extension an admission of guilt (as though the TSBs weren't proof enough) and loudly proclaimed that a full recall was more in keeping with this kind of problem. This was not entirely necessary, and three years later, well, Subaru seems to have a grip... not least because of the symmetrical all-wheel drive.

Now, if only they could go back to making 6-speed manuals, everything would be fine and dandy. I have shifted (pun intended), my gaze from the BR9 Legacy 2.0 Di-T to the Levorg STi

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I have done extensive articles on how different types of transmissions work, and that material features in my first book, Where There Is A Wheel. It took as many as four chapters to explain and compare these transmissions, pictures included, so you can understand my reticence about getting into it here.

It will take two months' worth of weekly articles to nail it down, by which point a large part of my readership would have suspended their subscription until I start writing about things they are interested in again.

However, we will be running excerpts from that book in MPA Magazine – check out motoringpressagency.com for more information.

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What about head gasket damage?

Well, I had to replace an engine because of this and the guy with the excessively warm Impreza in the preceding correspondence seems to be a likely victim as well. What is it they say about statistics?