How do I exorcise the demon of overheating from my Toyota Wish?

My Toyota Wish is overheating and cannot be trusted anymore. PHOTO | COURTESY

What you need to know:

  • The overheating issue need not be repeated, that is a clear and present problem.

  • This is usually down to either leaking cylinder heads or from cooling system flaws.

  • Two things exonerate the cooling system immediately, but only somewhat, the first being you performed some sort of overhaul on the system, albeit an incomplete one.

Hi Baraza,

I am an ardent fan of your column and I can say that it has greatly impacted us feverish motor zealots, with machines yes, but greatly dwarfed in mechanical know-how. Keep up the good work, man! On a sad note, my Toyota Wish is overheating and cannot be trusted anymore. I initially trusted her despite her sickly tendencies as the overheating signs were manifesting say after a 50km drive, or a long duration in a traffic jam. Now, in a duration of less than 15km, signs of overheating begin.

The vehicle simply loses power and is unable to move. Pump the throttle and it only purrs without moving forward, but the reverse gear is okay. Initially, it used to show the Check Engine light which would come and go off depending on the overheating status, but when I had the radiator flushed and unclogged by a self-proclaimed radiator expert, the Check Engine light no longer shows even when the vehicle has stalled after overheating. I have had the radiator cap changed, the radiator unclogged and flushed and employed too the services of a highly rated “radiator expert”, but the problem remains. Various theories of the genesis of the problem have been suggested and include:

1. Using tap water instead of the commercial coolant.

2. A stuck thermostat which should be removed and the vehicle left without any.

3. Warped engine block.

4. Damaged head gaskets.

5. Failing water pump.

6.Signs of a failing engine.

7. Toyota Wish vehicles are queer vehicles and display such weird behaviour when they age (so I should just accept and move on!).

And many other theories which can almost fill a 32-page exercise book! Now, Baraza, how do I deal with all these prophets of doom and exorcise the demons of overheating from my vehicle once and for all? Can the problem be diagnosed and processed through an engine scanner when the check engine light is not manifesting?

What is your ultimate advice to a Distressed Brother who has come to the end of his tether? I look forward to your usual very helpful, but sometimes mildly abrasive, responses to mechanically lethargic individuals like myself.

Kind Regards,

Lawrence Kamau

Hi Lawrence,

Another lengthy treatise concerning a convalescent Toyota, and what do you know, just like the first one, it involves heating problems and tearing open the engine block, probably. We solved the previous case, let us see where this one takes us...

The overheating issue need not be repeated, that is a clear and present problem. This is usually down to either leaking cylinder heads or from cooling system flaws. Two things exonerate the cooling system immediately, but only somewhat, the first being you performed some sort of overhaul on the system, albeit an incomplete one. You only focused on the radiator and forewent other components such as the water pump, the fans and the thermostat, which we will get to shortly. Anyway, the second pointer towards the cooling system probably not being the culprit, is that the heating problem has worsened over time, stalling the car, and that the car seems to have lost power. This is highly symptomatic of a cylinder head issue.

Now let us look at the guesses put forth as to the root of all your problems:

1. Using tap water instead of coolant: this one is summarily dismissed for several reasons. Tap water may cause your cooling system to degrade via gunk buildup and/or rusting, though this happens over a very long time. We are talking years and/or hundreds of thousands of kilometres. Plus, you say you redid the radiator, the cap et al, but the problem persists. Clearly this is not it.

2. Stuck thermostat: perhaps you should have started with this? Removal and rewiring of the fans to fire up immediately would have confirmed pronto whether or not the problem was with either of the two, but my proposed cure would not have been a complete thermostat-ectomy, it would have been more like a thermostat-plasty (replacement, rather than removal).

3. Warped engine block: this is highly likely. It would explain the worsening of the problem over time and the loss of power. It would be part of a vicious cycle: the warping is the result of overheating in the first place, but since it also causes overheating, it is a problem that makes itself worse, like self-teaching artificial intelligence. The origin of this would be a leaking head gasket.

4. Damaged head gaskets: this would be the underlying cause of No. 3 above. Checking for head gasket issues includes a compression test, physical inspection of the coolant for presence of oil slicks or an appearance of milk tea/Amarula in case oil/air-fuel mixture is leaking into the coolant and checking the oil for a white suspension in case coolant is leaking into the oil.

5. Failing water pump: I did mention this earlier, didn't I? This is mostly an electrical test but the initial stages involve cranking the car until it warms up then feeling the radiator hoses by hand for the kind of vibration that signifies flow of water. It is not a good test for two reasons: you risk burning your hand on the hot hose, plus the method is not exactly foolproof since the problem could be a malfunctioning thermostat failing to activate the water pump or a blockage impeding the flow of water and not the water pump itself.

6. Signs of a failing engine: well, you don't say. Overheating and power loss being attributed to a failing engine is kind of stating the obvious here, innit? Plus this is too vague: what part of the engine is failing and can this failure be averted?

7. Toyota Wish vehicles are queer and age oddly: well, I don't know. Actually I do, and you may have hit the nail on the head with this one. The Toyota 1AZ engine which is what powers the 2.0-liter Wish, is that the cylinder head bolt threads wear out in engines made before 2007. This wear causes the cylinder head to come loose, leaking compression and causing overheating and power loss. The best cure for this I'd propose would be an engine swap, preferably a downgrade to the 1ZZ found in the 1.8 liter Wish.

As for the Check Engine Light, pull a code using a diagnostic tool to see what the issue behind that is. It may or may not be related to the overheating.

What ails my beloved Toyota Belta?

Dear Baraza

On behalf of car enthusiasts, I applaud your contribution to the motoring industry. I would like to inquire about a certain whistling type of sound coming from my car when I accelerate. It's a 2009 Toyota Belta. I've had the car for over two years now. For one-and-a-half years, it operated as a Uber taxi until I realised that was making loses since it required repairs often. Since then, I’ve been personally using it and it has been running smoothly with no issues other than the whizzing sound when I press down on the gas. My mechanic says the gear box pump is to blame, therefore I should replace it, but he's been wrong before on another issue so I am hesitant to follow his advice. What do you think?


The Bull

Hekinah "The Bull"!

I have but one take: I cannot for the life of me tell what the whizzing - or wheezing, or whistling, or wincing or any such homonym - sound is because I need to hear it first and I need to triangulate its origin. Different components wheeze and whizz and whistle in different musical and non-musical notes. A leaking hose will whistle differently from a failed pulley, which in turn will wheeze differently from a shot bearing which will screech differently from a dying fan belt. I'm not about to start guessing based on the extent of your vocabulary and your ability to deploy it.

You also don't specify from what end of the car the noise emanates. The front? The back? The middle? The right? The left? You are asking me to take pot shots here.

Since I am not a mechanic, I will offer you two options, first ask your mechanic why he thinks it's the gearbox pump making that noise. He should be very detailed with his explanations, which you can cross-check on the web-net in real time as he speaks to verify how much of that information is solid and how much is being pulled out of his a--.

The second option is to get a second opinion.

What do you think about the Nissan X-Trail?

Hi Baraza,

I am addicted to your column, which I find very informative and entertaining.

I started driving way back in 1974 starting with the Safari famous Peugeot 404, then advancing to 504, 505, Audi, culminating with the Mercedes Benz. Upon retirement a few years ago, I decided to go low profile and acquired a seven-year-old Nissan AD import. I drove it extensively for almost a year and a half with no problem to complain of. Seeing so many X-trails especially on Mt Kenya roads, I decided to upgrade to a 2500cc X-Trail. So far, I have been immensely impressed with its performance overall, more so because I belong to the age who used to look down on Far East products. The reason I am writing is to ask why you rarely comment on Nissan vehicles. Give us your opinion on X-Trails vis a vis Toyotas, Mazdas, and Mitsubishis.

Keep up the good work.


Hi Geemar,

I do comment on Nissan vehicles. I like to say nice things about bucket list models such as the GTR and the Patrol, and I tend to mention the extremely long product cycles they seem to believe in, which in turn costs them as far as selling competitive products goes. The recent scandal involving their ousted fugitive CEO is the stuff political thrillers are made of, but is definitely not good for the bottom line.

Now, about the X-Trail. Which model specifically do you want to hear about? The first generation exploded into the scene to much praise and applause, what with its breeze-block silhouette, party-trick 4WD (for the time) and the availability of a 280hp GT model. I never really felt much for the center-placed instrument cluster and soon afterwards, people discovered it has a sensitive automatic gearbox that was especially susceptible to fluctuating ATF levels, and the GT ate ignition coils instead of eating Forester STIs. It is still the best of the lot.

The second model came with a yawn-inducing CVT and it grew fatter in appearance, but did not seem to lose much of the talent. The biggest upside was reverting the instrument cluster’s position to its supposed location where it illuminates the driver’s neck and chest, as it originally should have.

The third model is bland and anonymous, and you’ll be hard pressed to identify it in a line-up. It doesn’t seem to offer much beyond the growth of a third row of seats to make it a 7-seater, something that its bitter rival, the Honda CRV, managed a while back.

The aforementioned long product cycles are proving costly to the Nissan brand and subsequently its models. Taking forever to update your models means the competition has the time and space to innovate within their line-ups and make you look obsolete. Class leaders such as Honda are powering ahead in leaps and bounds, traditional rulers such as Toyota are not losing ground and young upstarts like Mazda are really shaking things up especially in the fields of driving dynamics and car design. Don’t forget the Koreans who entered the second decade of the 21st Century with an intention of causing an upheaval by being as good as, if not better than, the Japanese and Europeans at a fraction of the cost. It is not a promising time for Nissan.

Mitsubishi is just Mitsubishi.