Hyundai advice.

[RS13]

The in-laws Hyundai Getz is using oil, like, a litre and a half in the last couple of months however it doesn't leak or have noticeable oil smoke off idle or under load. Had a look at it last night, found light brown sludge under the oil cap which would suggest either a BHG or the engine not warming up enough to burn it off.. however the coolant level was spot on, it doesn't overheat (if anything, the gauge took a long time to come up which would suggest the thermostat is shagged) and it gets long-distance driven daily. Looking through the oil filler hole I did notice a fair bit of coking.. would the oil usage and moisture perhaps be a result of a blocked crankcase/PCV vent line? Not the most well-serviced car, but not exactly neglected and with 165kms of hot running I'd be hesitant to point the finger at the rings?

[andyztouring]

Has the car been running on Castrol oil?, some grades of Castrol is very bad for slugding up and high oil consumption,more so with shorter cold running.With many of the Hyundai engines being based on Mitsubishi engines,oil useage could be a feature .I would be checking for worn valve seals then worn rings.

[sergei]

it is a Hyundai .
Regarding comment on Castrol oil causing sludge I disagree, using any oil in a neglected or tired engine could cause sludge.

What spark plugs look like?

Valve stem seals could be the culprit, if it an auto, put in '2' when going down hil and watch the rear view mirror (basically mid-high rpm engine braking). Does it puff for a second or so on cold start?

Otherwise it could worn oil control rings.

Open the oil cap (carefully) when it is running and see if any smoke comes out. If smoke == rings are most likely kaput.

If PCV system was blocked it would leak oil through every orifice and seal.

How thick is the sludge (can it be wiped off with the finger)?
If there is only light coat of sludge, you could switch to diesel oils (they have little bit more detergent) and frequent changes. Anyhow if the car is consuming oil the frequency of oil changes must be increased (eg. every 5000km instead of 10000km).

There is a possibility of sludge causing the oil control rings to "stick". Frequent oil changes and heavy foot/high rpm can remedy that in early stages.

If there is more than a surface build up of sludge, then forget about it. Don't bother using engine flush as it might cause the sludge to come loose in clumps and block the oil strainer/pickup line (which equals to bottom end kaput).

Besides, Getz is a piece of shit, get a Honda or something .

EDIT: I just noticed the comment about taking a while to warm up. If the thermostat was stuck open for a long period, causing engine run too cold all the time, it is possible that ECU was running in warm-up mode all the time, thus over-fuelling. The constant over-fuelling causes bore wash (excessive wear of the bores due to lack of lubrication cased by fuel removing/diluting oil) thus causing oil consumption. There is no cure for bore wash (except re-hone+new rings if tolerances allow).
The running cold all the time can explain milk chocolate type of deposit on the oil cap.

[RS13]

Thanks guys.

No idea what oil it ran previously, as I mentioned it belongs to my in-laws so I don't see it very often. The sludge under the oil cap has the consistency and colour of coffee foam.. it had done an hour-long run into town and then parked up so I'd have expected it to burn off. Although thinking about it now, on top of the thermostat being buggered they also have the aircon on all the time which means the radiator fan/fans are constantly running, even on frosty mornings.. which I guess would mean it would take even longer to warm up. I idled it with the occasional rev or two for a good 20 mins, it only ever reached 1/4 the way up the gauge so I'm pretty confident that lack of hot cycling is the issue, has also been run very low in oil a couple of times now (had a loud top end rattle when warm until I topped up the oil) so I think its' not worth doing anything with. Time for a new car methinks!

Cheers for the advice, interesting about them being copies of Mitsubishi engines.

[sergei]

Cheers for the advice, interesting about them being copies of Mitsubishi engines.

Licenced . See: https://en.wikipedia.org/wiki/Global_Engine_Alliance

And before GEMA Hyundai licenced engines from Mitsubishi (think of 4G6X series).

Regarding not doing anything about, I suggest at least replacing thermostat and changing oil again after (in case if it is contaminated by fuel). This will increase fuel economy (probably by about 10-20%).

[RS13]

Was reminded of this the other day. Changed the failed-open thermostat and 40,000km old oil (which came out in lumps!) a few months back, hasn't needed any oil since. Reaches temperature and switches on the fan now (for the first time in years most likely!) and with the Magnatec (gimmick or not, it was half price!) also runs very quietly compared to before. Still unsure where the oil was going before as it still doesn't burn or leak anything more than a slight cam cover seep.. either way I'm calling it good.

Cheers for the help fellas.

[85AW20v]

.... Changed the failed-open thermostat and 40,000km old oil (which came out in lumps!) a few months back....

Maybe this where the oil went....

[Bling]

40k between services, yikes! Granted my work van can do 30k intervals, but that's a different kettle of fish. (it's done yearly as I don't get close to 30k)

Good result for the inlaws though, I bet the inside of the engine looks similar to mine when it blew up, minus the metal flakes. (not in my ownership at the time FWIW).

[sergei]

40k between services, yikes! Granted my work van can do 30k intervals, but that's a different kettle of fish. (it's done yearly as I don't get close to 30k)

Good result for the inlaws though, I bet the inside of the engine looks similar to mine when it blew up, minus the metal flakes. (not in my ownership at the time FWIW).

Generally the cars that have long recommended services have simply more oil in the system (ie: 4L vs 6L or 8L), they also specify some Group 4 synthetic.

[RS13]

Still running quite well, haven't heard any complaints and when I've checked myself it hasn't needed anything other than a slight coolant top-up which I think was just an airlock from when I replaced it.