"HI" Oil warning message on R129

[Mad_Minty]

This has just started happening with regularity on my SL500 R129.

Until recently this warning message - oil can with the blinking letters HI - had only occurred once and that was after working the engine very hard (if you catch my drift) for several minutes. I am assuming that this warning is self-explanatory, as in the oil temperature is getting too high? I can find no reference to it in the manual.

But now it happens every time the oil temperature passes the 70c mark. The needle settles around the 90c mark, although there are no further ticks from 70 to 150 so it's hard to be precise. Seems to me that median temperature is OK?

So perhaps I just have a faulty sensor, or is there something more sinister at work?

Thanks in advance.

Martin

 

[stats007]

It's oil level and not temperature. Have you had it changed recently? The sensor has been known to go wrong of course.

 

[stats007]

Hello Martin .

 

[television]

Hell Martin and welcome, there are some listed things for the high oil level erroneous reading and I will look them up this evening

 

[stats007]

The sensor measures temperature, quality and level. If you've been giving it the beans I believe the sensor can trap air - I'm sure Malcolm will be able to tell you as the engine is common across the range. There have been three revisions - though probably down to supplier rather than design changes in all of them. The current sensor is about £70 - part A0061532728 if you need it.

 

[Mad_Minty]

Hi guys,

Thanks for the clarification.

Andrew - good result last night. Perhaps I'll bump into you at the Carling Cup final

Malcolm - thanks for the welcome. In case you were wondering why Stats is being so familiar with a newbie, I am the new proud owner of his Silver Arrow. It's good to know that "maserati boy" hasn't lost his touch with MB knowledge :bannana:

I've put about 5k miles on the car in the last 9 months so I haven't thought to change the oil. I did immediately check the oil level and it registered max. It struck me as odd that she hasn't burned any oil over that mileage but a reading is a reading, no? I am surprised that the manual makes no reference to this warning. I guess this is how main dealers made all their money before the Internet democratised knowledge!

I'm keeping an eye open for further sage words from Malcolm.

Cheers,

Martin

 

[stats007]

The SLs I've owned have never used any oil - did you take the reading using the instrument cluster or the dipstick?

I would imagine the sensor is playing up given that it had a full B service at MB World the day before I sold it to you. Whether it can be removed and fixed I don't know without looking it up - hopefully Malcolm can do this before he goes away . It looks like this anyway:

 

[television]

One strange note by MB

Tank contains foreign substances like diesel or additives = replace engine oil.

Another
If the level is correct on the dip stick, have the cluster re set on STAR.

This fault could be stored and read out out.
Could be sensor
This could be the one.

Oil sensors with number production dates up to 00W51 can cause implausible overfill warnings when the temp reaches 60-70c

​

Fault code P1177 or P1178 alone or P1178 and P 10097 together = replace oil sensor

Hope this helps
​

 

[Mad_Minty]

Oil sensors with number production dates up to 00W51 can cause implausible overfill warnings when the temp reaches 60-70c

That sounds like a strong candidate because it's always exactly that temperature range when the warning first occurs.

I originally checked the oil level with the dipstick and then, after prompting from Stats, reminded myself how to check it from the console. That digital check reproduces the same "HI" error. Given that I have not added any oil in my nine months of ownership, and she had just had a B service before that, would all lead me to believe that the sensor is at fault. I'll wheel her into the MB shop and see what their hi-tech gadgetry says.

Thanks for the quick assist.

Martin

 

[Mad_Minty]

Just to close this thread off cleanly, my local MB Shop agrees that the problem sounds like a faulty oil sensor and has ordered one. I am dropping her in next week and will post the final conclusion for future reference.

Martin

 

[Mad_Minty]

Well, the final chapter in this saga is a satisfactory but mysterious ending!

After a quick visit to MB Stevenage (who had ordered in an oil sensor just in case) they diagnosed the fault as: too much oil in the engine !!!

How is this possible after driving for 6 months since the last B service and not having added an oil? Why did the fault occur once when 'giving it the beans' and then disappear for months and then came back permanently? All very difficult to figure out. One can only assume that the level was marginal.

I was impressed that, at the dealership, they can suck oil up through the dipstick hole so the fix took about 30 seconds rather than the however long it would take for a numptie like me to drain from the bottom (I am not handy). And they didn't even charge me a dime! All credit to MB Stevenage as this is the second time I have visited them with a minor ailment and they have waive any charges. Good job as the estimate for changing the oil sensor was £400 and requires an overnight stay to allow the sealant to take.

Martin

 

[stats007]

Sounds odd - though the sensors aren't that accurate. Did I give you the spare oil? I supplied it to MB Brooklands for the service.

 

[maddog]

I had similar happen with my E class , the dipstick read bang on full but every now and then the oil level warning would come on , it didnt start do it for about 6 weeks after the service i guess when it got hotter (car was serviced in Feb)

Took about 5000 miles of ever decreasing warnings for it to stop all together

 

[television]

Oil expands when its hot, it can absorb other things, these were common complaints 18 months back, not very many now

 

[kth286]

A lot of short journeys can make the oil level rise because of condensation etc .

Of course it is NOT oil but nasty fluids that need to be got rid of asap.

You will notice after a long drive with engine up to full temp that the oil level will have dropped significantly because the nasties will have been got rid of.

OF course if there are lots of short drives then it comes under the Mercedes arduous conditions catagory and the oil change interval should be much more frequently.