Random questions about everyday cars

[vyselegend]

Hi people! Long time no see... I wish you the best possible 2010 year!

Actually I came up with the idea of this new thread because I regulary have a few trouble with cars in my everyday drives, and I thought F1T was a correct place to ask, as there is a good bunch of qualified people (and experienced drivers) here.

Anyone can feel free to hijack this thread to ask his own questions.

1) Excessive fuel & oil consumption.
These days in Paris I use a '97 60HP Smart Fortwo (petrol / sequential gearbox) to get to work in the suburbs. It's a great car for low consumption, and I usually manage to do approx 280 km with it's 23L fuel tank in this fuel eating city.
But since my last filling (in a regular Total gas station), the fuel guauge has been getting down very quickly! In the end I emptied the tank in less than 240 km, despite driving normally! Also, just before chrismas I had to fill the oil tank too, although I had it filled in september... Seems quite a big lubricant loss to me.

I know cold temperatures are bad for fuel mileage (we currently have from -8°C to 0°C), but the difference seems too big to me: a 40 km loss on such a tiny tank feels weird!

So, what do you guys think about the engine? Is it possibly leaking? (I couldn't find any trace of fuel on the ground under the car). Is the fuel consumption related to the oil's one? (some ppl told me it's normal for old petrol engines to become oil thirsty)...

2) My second question is about a 2.5l turbo diesel Nissan Navarra pick-up I borrowed to a friend the other day. It was an ok drive, but at one point I reached the 2500 rpm mark in 2nd gear, and the engine kicked in some sort of "safe-mode" (or so I suspect) and there was no torque anymore, nearly no power was coming out of the engine untill I restarted it...

When I told it to my friend, he said it had happened to him a couple of times, always while getting around 2500rpm on the three first gears. It once happened to him while trying to insert himself on the highway, and it was quite a dangerous moment!

At the Nissan dealer, they denied anything about a safe-mode or electronic bug, yet they insisted it was advised not to push past 25krpm especially in the first ratios...

Anyone had a similar experience?

[marcush.]

Hi people! Long time no see... I wish you the best possible 2010 year!

Actually I came up with the idea of this new thread because I regulary have a few trouble with cars in my everyday drives, and I thought F1T was a correct place to ask, as there is a good bunch of qualified people (and experienced drivers) here.

Anyone can feel free to hijack this thread to ask his own questions.

1) Excessive fuel & oil consumption.
These days in Paris I use a '97 60HP Smart Fortwo (petrol / sequential gearbox) to get to work in the suburbs. It's a great car for low consumption, and I usually manage to do approx 280 km with it's 23L fuel tank in this fuel eating city.
But since my last filling (in a regular Total gas station), the fuel guauge has been getting down very quickly! In the end I emptied the tank in less than 240 km, despite driving normally! Also, just before chrismas I had to fill the oil tank too, although I had it filled in september... Seems quite a big lubricant loss to me.

I know cold temperatures are bad for fuel mileage (we currently have from -8°C to 0°C), but the difference seems too big to me: a 40 km loss on such a tiny tank feels weird!

So, what do you guys think about the engine? Is it possibly leaking? (I couldn't find any trace of fuel on the ground under the car). Is the fuel consumption related to the oil's one? (some ppl told me it's normal for old petrol engines to become oil thirsty)...

2) My second question is about a 2.5l turbo diesel Nissan Navarra pick-up I borrowed to a friend the other day. It was an ok drive, but at one point I reached the 2500 rpm mark in 2nd gear, and the engine kicked in some sort of "safe-mode" (or so I suspect) and there was no torque anymore, nearly no power was coming out of the engine untill I restarted it...

When I told it to my friend, he said it had happened to him a couple of times, always while getting around 2500rpm on the three first gears. It once happened to him while trying to insert himself on the highway, and it was quite a dangerous moment!

At the Nissan dealer, they denied anything about a safe-mode or electronic bug, yet they insisted it was advised not to push past 25krpm especially in the first ratios...

Anyone had a similar experience?

leaking fuel and oil without a trace below the car is impossible... if you ever had an oilleak of 1 litre over 3 months you can be damn sure your usual parking slot is a complete mess and your landlord ,the police or someone else had already grabbed your throat..
With the excessive fuel consumption + oil burning it looks likely that your engine has developed as small being unwell ...maybe the piston rings or something like the valve seals .. the smart engine is not known for its robustness i believe.so maybe its time to get the engine checked before the small illness develops to a big disease.. taking the live of the Cat as well...with todays obd diagnosis I am a bit surprised that you did not already get an MIL error on the display ???

[mx_tifoso]

Even if the Smart hasn't gotten any error messages you should take it to your dealer or an independent shop to get it checked with the OBD scanner. Some codes might pop up. Maybe it's running to rich?

Or perhaps someone else drove the crap out of it without you knowing?

About the Nissan, get it checked as well. Here in the US we have places that'll do it without charge, is it the same in France?

It's nice to see you've returned Vyselegend. Welcome back.

[Carlos]

Valve Stem Seals

I don't know much about computer engine codes, I preferred working on pre-computer engines - So I'll give an 'Old School' answer. First thing, buy a shop manual, second buy an inexpensive compression gauge. You may also need a piston ring compressor and a 'cutter to clean carbon 'above' the rings if you need to do a ring job.

I'd agree - It sounds like the valve stem seals need to be replaced, with age they sometimes crack and leak oil into the cylinders, pull a sparkplug and 'read' it. Hears a good 'picture guide' to reading a plug, if it's black and 'sooty' the valve stem seals need to be replaced.
http://www.ngksparkplugs.com/tech_suppo ... aqread.asp
I suspect the engine might have been overheated a time or two and 'cooked' the valve seals and/or burnt a valve, cracking off a sliver/chip of material so the valve no longer seals, that would account for the gas milage suddenly decreasing.
While you've got a sparkplug out, check the compression for all 3 cylinders with the gauge, referring to the manual for pressure values. There's a choice, does the engine need valve seals, a head job or piston rings. If the pressure is low, squirt a bit of 30W oil into the cylinder. If it's the rings, when you check the compression of a cylinder, it will be higher, as the oil 'seals' the rings. If the pressure doesn't decrease, but is low - it is a valve problem. Here's some general links to help out.

http://www.ngksparkplugs.com/tech_suppo ... aqread.asp
http://www.enginebuildermag.com/Article ... esigns.asp
http://www.aa1car.com/library/compression.htm
http://www.allpar.com/eek/ValveSeals.html

With care you could replace the valve stem seals with the engine in the car. If it needs a valve job or just one valve, you could pull the cylinder head with the engine in the car.

If you have to pull the engine out to replace the piston rings, the good news is it's so small, one man can lift it out and you can work on it on the kitchen table.

[vyselegend]

Ok, thanks for the answears guys!

I think I'm going to ask for a OBD check by a Smart center as suggested, hoping it's going to be cheap...
Thanks Carlos for the detailed information, valve stem seals damage is the most credible explanation for a fuel loss without visible leak, as far as I understand it. But I'm not feeling very confortable with the idea of fixing them by myself, especially considering that the three cylinder block is barely accessible with child hands, hidden under the small trunk...
I'll probably be paying in the end, as usual...
Anyway I understand I should fix that quickly, since it dries the engine out of it's oil, and that can't be good if I don't want to take the train again!

Or perhaps someone else drove the crap out of it without you knowing?

How did you know my father drove it?!!

I suspect the engine might have been overheated a time or two

Very probable considering the amount of time spent in traffic jams in this damned city.

About the Nissan, get it checked as well. Here in the US we have places that'll do it without charge, is it the same in France?

It's up to my friend to do the work, but I'd say nope. Nissan haven't been very friendly on that matter (they did a quick check but denied there is a problem), nor they were on other matters, like asking 700€ for the GPS updates!
Still, this is a great pick-up when you put that electronic problem aside...

[marcush.]

not the smart specialist ,but i seem to remember the smart has a turbocharger ,which hints to som e possible problem.

Tubochargers put a lot of strain to the exhaust valves so maybe we see the problem a bit clearer now.
Also you did not mention if you have found the litlle thing performing worse than in earlier days ...maybe also some rough running or sawing in idle... if the valves are
not closing properly this will inevitably lead to a loss in performance at low revs
and intermittent/rough idle idle although this may be masked by the charger a bit .
But then i heard about smart engines only lasting 50.000kms..

[vyselegend]

But then i heard about smart engines only lasting 50.000kms..

That sentence give me the shivers. Mine is 53.540 km already... And indeed every magazine agrees that those early models suffer numerous reliability issues.

I'm puzzled by the situation anyway, because while I really had the huge mileage deficit I described, the next filling (from the same Total gaz station) make me break a record with that car, with over 310 km covered with 23 litres!

So I've got only two suspictions. Either the quality of the fuel can somehow vary even within the same (reputed) fuel provider, or (most credibly), the fuel guauge on the smart (actualy an lcd display) is tricky.

I'll bet for the second option, because I think the lenght of piping between the fuel tank and the trap is worth a few litres (maybe up to 5)and that could explain there is a big difference between a "normally filled tank" and one over filled like I did last time.
Or there is still the third option that the very cold temperatures (near -10°C) we had for some times made the engine burn a lot more fuel...

Anyway thanks for the advices, and sorry I haven't replied earlier, as my internet conection was down for a week...

[Belatti]

Or there is still the third option that the very cold temperatures (near -10°C) we had for some times made the engine burn a lot more fuel...

And also oil. Remember the pistons take longer to achieve its designed shape and so the rings do not do their job as usual with a cold and "tiny" piston. I have seen many time white exhaust fumes in recently started cars with temperature far away from the working one.

[vyselegend]

I'm sad to bring back that thread, because it means I've got new troubles with my car(s).

It's about the Smart fortwo again.
Today I've spent some very good time with my wife in Vincennes, enjoying a very warm and sunny weather, but as we came back in the center of Paris, I heard a sound alert (bip bip...), and quickly realised it was related to the cooling temps, as the digital display reached the fourth "case" (there are five), meaning cooling fluid temps are up to ~90°C / 100°C.

I tried to drive slowly a bit more, because we were so close from home, but in the next 100m, the display reached the fifth "case" (temps around 120 °C) and the bip bip never stopping, so I took it as a serious one and stopped immediatly.

I've opened the engine bay wide, and checked fluid levels. lubricant was ok (although it's strange it was still at max after so much time since I've refilled it, so I suspect high engine temps made it's pressure raising too much). Cooling fluid was quite low, but not empty (approx. 1/4 of the tank capacity).

As I was near a gaz station, I've bought some cooling fluid and immediately refiled the tank, while letting the engine bay open for 1/2 hour.

After that time I started engine again (temp display was back to second "case"), and safely completed the last hundred of meters separating us from home. But in that short time it quickly jumped back to third "case" (although without the bip bip alert).

I've waited for some time after parking the car, and checked the ground to be sure there's no fluid leakage. I've spotted nothing.

But there's a strange symptom which makes me think it could be related with some of the electric devices in the engine (a pump maybe?):
When I turn the key first step (as to activate electric systems), I can hear a disturbing grating sound from engine bay. It occurs again while the key is turned back to initial position (electric systems off). The sound reminds the one of a grating rusted metalic portal, and lasts around 1 second each time.

Obviously it won't solve by itself, so I'll have to bring the car for a serious check soon, but I'd like to have your opinion about which parts could be suspected for that overheating problem.

Anyone?

Notes: Today was around 30°C ambient temperature. The car is a 97 (or 99 I don't remember) Smart Fortwo (gazoline). It has passed the 55500 km mark.

[mx_tifoso]

Time for an engine swap.

Not sure what that car has for a cooling fan on my car its electric. The cooling fan motor or controller might be shot. Check the fuses first.

[youtube]http://www.youtube.com/watch?v=cV4HdsDZX6c[/youtube]

[vyselegend]

Thank you flyn', I think you're on something with the fan!

Sounds obvious now, but I haven't even thought about it, despite watching it motionless saturday (but I had only remarked it was standing still after 10mn/20mn with engine cover off, so I just thought it had stoped naturally).

If that's really the problem, I don't think it will be very expensive. So I hope it's nothing more than a dead fan (toasted coil or wathever...)

Thankfully, I can borrow my father's 207 CC (nice timing to get a cabriolet with that warm weather!) this week as he's away, so I'm not pedestrian... I'll bring the Smart to repair wednesday or thursday, and I'll let you know how it went.

Thanks.

And that Hayabusa Smart sounds crazy

[ISLAMATRON]

Turn on the car and let it idle, check and see if the fan spins... if not turn it off and tap(hit) the fan motor with something solid... but not too hard. With the key out of the ignition, see if you can spin the fan blades with your hand.

[flynfrog]

Turn on the car and let it idle, check and see if the fan spins... if not turn it off and tap(hit) the fan motor with something solid... but not too hard. With the key out of the ignition, see if you can spin the fan blades with your hand.

I would unplug the battery first some can still turn with the key off

[ISLAMATRON]

yep, that

[marcush.]

hm ...would the temp rise this quickly with the car moving? an easy test would be to try and drive fast ,when it is still overheating for sure its not the fan.

I would tip more on a stuck thermostat or a non operational water pump.

If the thermostat does not allow for coolant flow to the rad your car will tend to overheat as there is not much in terms of cooling cpacity.
also if the thing is soooo hot 120°C I´m sure this would look like a gaisir after opening the watersystem...

so maybe its the Temperature sender giving wrong info to the engine/display...?

so first check the tempsensor and real water temps
then check if thermostat is operative (can remove the thing for a test)

I had something like this with a blocked waterpump (new part) it looked normal but when you tried to put load on the engine it quickly overheated ...like the jammed thermostat..

worn away (rusted ,or eroded away by abrasives...can eat away at waterpump power..
this will of course not move water anymore -leads to overheating...