| Last week the oil temperature of my E220 Bluetec went up to 134 ° C(273°F) during a trip to the mountains. Is that normal? Car mileage : 195k miles The oil was Mobil Super 3000 xe 5w30 changed just before the trip. Outside temperature: 34 ° C (93°F) . Coolant temperature: 92 -97 °C (197-206°F). The max oil temp was reached after about 30 minutes of uphill driving. After 5 minutes of downhill driving with the foot of the throttle the temp quickly went down to 118-120°C(243-248°F) Are those oil temp readings normal? Am I causing permanent damage to the engine? Usually my oil temps are around 99-105°C (210-220°F) with fully warmed up engine driving on the freeway at 70-75MPH. If the car is loaded or I push it harder oil temps may spike for a short time up to 120 ( 248) but only for short periods of time. So I was a bit scared seeing an oil temp of 273°F. Should switch to a 40w oil? My oci is max 5k miles and I use the car mostly on the freeway cruising at 70MPH Thank you for your responses |
High oil temps
- Thread starter Costas00
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I would not be concerned about the temp in those conditions. 30 minutes at that temp should not harm your oil or engine.
If you are going to make the same trip again in the near future, you can try a 40 weight and see if temps are better. I have a feeling you are fine with your current oil though. Just make sure you use the same type of oil if you change weight for protection of your emissions system.
Does your EU CDI have a DPF that has to regenerate? Wonder if the uphill drive and a regeneration combined could do that. If you have a DPF that has engine controlled regeneration you probably just deep cleaned your DPF if the above happened.
The VW TDI runs exhaust temps close to 1,000 degrees F (~530 C) during regeneration to burn off the DPF and imagine any other auto with a regenerating DPF would have to hit the same temps. It was hot enough if you stopped the car in the middle of a regeneration the cooling fans would stay on for ~15 minutes after parking to cool everything off.
The VW TDI runs exhaust temps close to 1,000 degrees F (~530 C) during regeneration to burn off the DPF and imagine any other auto with a regenerating DPF would have to hit the same temps. It was hot enough if you stopped the car in the middle of a regeneration the cooling fans would stay on for ~15 minutes after parking to cool everything off.
Yes the car is equipped with a DPF and SCR. The engine is the OM651. Until now I haven't been able to notice a regeneration going on. When I stopped the car I let it run for about 5 minutes at idle but I didn't notice any heat or smell coming from the car. Engine noise was as usual. Next week I have a service appointment and I can find if a regeneration was going on with the Xentry diagnosis. I think every regeneretion is recorded in the car's ecu along with the date, mileage, coolant and oil temps.
I am thinking about switching to Ravenol RUP 5W40. Do you have any experience with ravenol oils?
One thing you did not mention was the average rpm during the run. It’s high rpm that causes high oil temperature. Various charts and calculations can predict the resulting viscosity at that temperature. It drops a lot. That’s why folks who put their car on the track prefer to use a Xw40. They also tend to install an oil cooler if doesn’t have one. I’m not sure if Mercedes specs a xw30 for that car, or if they do not spec a grade at all. If you do runs in the mountains a lot you might consider going up a grade. Perhaps you do the runs more in the summer than the winter, in which case you could run xw40 in the summer.
Mercedes doesn't call for a specific viscosity. The oil specs allowed for this engine in the manual are 228.51 and 229.31 229.51 229.52. These specs cover the following viscosities: 15w40 10w40 5w40 0w40 5w30 0w30. During the mountain drive the engine was running most of the time from 2k-3k rpm as the torque in this band was more than enough. The engine does not have an oil cooler. Only an oil to water heat exchanger. As far as I know the oil temp sensor mesaures the temp in the sump. So I suppose that the oil entering the engine will have a lower temp than the sump temprature or am I wrong?
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Yes, you probably would be correct on that, it will be cooler, but not cooler than the water temp in the rad. Since Mercedes has given the OK essentially of using a xw40 oil I would recommend choosing one of them. If you use the search function in this forum, with your name and words “oil temperature” you will be able to see posts about other folks experience with oil temperature issues. Good luck. PS, I’ve been to Greece twice. Wonderful country and people.
The other thing that increases oil temperature during mountain driving is the continuous operation of the turbocharger while climbing hills. The oil is used to cool the turbocharger bearings and heats up. This is another good reason to select one of the xw40 motor oils. 
Here is the temperature profile for Athens.
Seems pretty normal for the ambient temps and long uphill pull. Good news that it cooled quickly on the downhill.
I would not worry about the engine but if you do this trip several times within one OCI you might do a short service... 270F is borderline for conventional oil, but I suspect the Mobil Super has some synthetic content (blend).
I would not worry about the engine but if you do this trip several times within one OCI you might do a short service... 270F is borderline for conventional oil, but I suspect the Mobil Super has some synthetic content (blend).
I assume car manufacturers consider there are people driving outside of Florida
Is Florida really as flat as they say?
Flatter than that!
I think the 5w30 grade is ok but if you anticipate more of the same type of outing perhaps a better quality oil would better withstand those high oil temps.
Highest point: 345 feet 
https://www.bing.com/images/search?...D1A78AA&selectedIndex=1&FORM=IRPRST&PC=EMMX04
https://www.bing.com/images/search?...D1A78AA&selectedIndex=1&FORM=IRPRST&PC=EMMX04
Oh my. Well that appears to be real then! They also say things like "you do not need AWD" especially in a hot flat place like Florida so does that also apply, lol
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