[wlb50]

In the years I’ve been on this board the subject seems to come up periodically.

People in a tizzy because it’s reading almost 0 on a hot summer day.

I’ve used synthetic oil in this car since it was new. Well I know the previous one owner to this 1996 SL500 also used synthetic oil.

This is mobil 1 5W-40

Sold in the US under the Mercedes-Benz label at dealers.

This is what I’ve used since I got it in 2013.

Note the outside air temperature which was over 100° about half an hour ago

And I’ve had this reading in my 300 E in the summer and had driven it almost 400,000 miles

Nothing to worry about folks, just move along 😁

 

[carltwo]

What about exact same condition as your pic, engine running, however the red light is on in back of 0 pressure mark ?

 

[wlb50]

What about exact same condition as your pic, engine running, however the red light is on in back of 0 pressure mark ?

I have never had a red light on.

If you have a red light I would definitely get it checked

maybe towed

 

[wlb50]

Here’s the same car after it sat cooling for a few hours.

Note the pressure is now at 2 bar.

I think with the advent of lower viscosity oils, and particularly synthetics, this is one of the main reasons Mercedes has taking out the oil pressure gauge. Too many worried customers going to their service advisors

 

[rayhennig]

I've never seen my M104 engine oil pressure that low - close to zero, aside from zero intermittently when the gauge was faulty. A thump on the dashboard would restore it t around 2 bar, as normal.

After a hill climb with aircon in recent 40C temperatures, I've noticed an occasional drop at idle to about 1.7 bar. No cause for concern.

Also, of course, is the sender accurate? Is the gauge accurate. I spend a few hours with my local garage man verifying that the oil pressure was good, as was the sender. It was tha gauge playing up.

RayH

 

[Josh]

I read once in the owner's manual of my 500SE that it is not uncommon to see low oil pressure readings, especially at operating temps on exceptionally warm days. As long as the pressure gauge shoots up to 3 bar when you get on the accelerator, everything is fine. If oil pressure doesn't rise immediately, then there's cause for concern.

 

[MAVA]

Hey Bill,

Not to start a pissing war over oil, but you should strive to have that gauge higher in its worst condition. Three-hours later the gauge is higher. That not a test. Even the days when I was in bumper to bumper on those 105-110 days I was at 1 with my 235k mile m119.

I would test your gauge and cluster. The gauge goes from 0-43 PSI. Go to the next thicker grade of oil...

i would not be driving around with 0 at idle on hot days..

Here is oil card for the M119

Martin

 

[FATHERTIME]

I live in SOCAL and travel the southwest so when I got my 98 SL500 M119 and saw that near zero pressure with the dealer oil it scared the crap outta me cause my 94 SL320 M104 stays at 3 bar, lowest maybe 2 .I went to Castrol GTX 20/50 in all three of my SL's and put a new pressure sensor. I don't like synthetic anyway cause it likes to leak through gaskets. So when I got my 99 SL600 I saw they eliminated the pressure gauge in lieu of oil temp?. Guess too many complaints I have used GTX 20/50 for many years and in all the race engines I have built and never an issue. I frequently drive well over 100 mph across the deserts with temps over 100 degrees and want to see pressure on that gauge when I stop.

 

[Josh]

After I switched to Mobil I Delvac 15W40 in the 500, I noticed that my lowest pressure readings weren't nearly as low as they used to get when the car was serviced with 10W30.

 

[MAVA]

I live in SOCAL and travel the southwest so when I got my 98 SL500 M119 and saw that near zero pressure with the dealer oil it scared the crap outta me cause my 94 SL320 M104 stays at 3 bar, lowest maybe 2 .I went to Castrol GTX 20/50 in all three of my SL's and put a new pressure sensor. I don't like synthetic anyway cause it likes to leak through gaskets. So when I got my 99 SL600 I saw they eliminated the pressure gauge in lieu of oil temp?. Guess too many complaints I have used GTX 20/50 for many years and in all the race engines I have built and never an issue. I frequently drive well over 100 mph across the deserts with temps over 100 degrees and want to see pressure on that gauge when I stop.

Nice tip, I will do the same.

What is the grade of oil you are running on? or is it 20w50?

Does your M120 have the oil pressure port screw plug? or did MB cover the hole in the casting?

I blew the engine on my W210 which has a M112, and it too has no oil pressure gauge, and I want to do something like this:

But... I want a sensor right-out of the block(too not have hoses) going to PIC chip/Arduino(Microprocessor Controller) to a small LCD and a buzzer to chirp or buzz away, and hidden in the ashtray, or tap into the Temp LCD and have it roll for so-many seconds on each. Very doable on one of today's micro-controllers.

Martin

 

[FATHERTIME]

Nice tip, I will do the same.

What is the grade of oil you are running on? or is it 20w50?

Does your M120 have the oil pressure port screw plug? or did MB cover the hole in the casting?

I blew the engine on my W210 which has a M112, and it too has no oil pressure gauge, and I want to do something like this:

Martin

I use Castrol GTX 20W-50 conventional change at 4k I think those that do the dealer 10k abide by the speed limits
I drive my cars hard every chance I get, thats what the R129 is made for. As for oil pressure output I need to look on the M120. My M119 does fine pressure wise so I assume the M120 does also even thought it uses temp that equals coolant temp Maybe a tad lower.
One more thing here, that oil card you posted comes in the owner packet It states 20W-50 for my area ambient, So tell me why the dealers push 5w-30 on these engines They were not built for the thin stuff.

 

[Lee Wireless]

I use Mobil 1 0w-40 in my Florida driven 95 M119. Initially, I also had low pressure at idle on a hot day. Changed the pressure sensor and now stays at 1 when I come to a stop. And I've been using 0W-40 since I bought the car in 2001. It had 20K miles when I bought it and is now sitting at 160K.

 

[MAVA]

One more thing here, that oil card you posted comes in the owner packet It states 20W-50 for my area ambient, So tell me why the dealers push 5w-30 on these engines They were not built for the thin stuff.

John,

Thank you for your reply. I think two-things:

A) EPA is hounding them for better MPGs, and maybe they can pitch that to customers about better MPGs
B) A very suttle way to wear-out the engine on those hot days... as every car has a projected end-of-life, and it is not what every person on this forum thinks it is, so why not try to make that number???

Along those ways of adding wear to a car is why manufactures now under rate radiators on ALL cars, and Big Full size trucks. The moment 80-90F hit those fans are roaring on every car. These 90's and early 2k cars come with big radiators, but all the new stuff have tiny radiators - designed for controlled for "economic obsolescence"??

Martin

 

[FATHERTIME]

IMO The guys that speak of year models need to understand that the M119 M120 and M104 are pretty much pre synthetic engines all three are DOHC. I think when Chrysler came on scene clearances changed in the SOHC motors also EPA crap M113 is not the same animal many of them along with the V6 are plagued with the secondary air plug ups in the heads that I blame a lot on those extended oil changes and synthetic oil. Thank You Mercedes for keeping Chrysler out of the M120

 

[rayhennig]

I've never seen my M104 engine oil pressure that low - close to zero, aside from zero intermittently when the gauge was faulty. A thump on the dashboard would restore it t around 2 bar, as normal.

After a hill climb with aircon in recent 40C temperatures, I've noticed an occasional drop at idle to about 1.7 bar. No cause for concern.

Also, of course, is the sender accurate? Is the gauge accurate. I spend a few hours with my local garage man verifying that the oil pressure was good, as was the sender. It was tha gauge playing up.

RayH

I have a simplistic view of this oil thing based on the assumption that modern synthetics remain thin when cold and maintain their viscosity when hot. So, that covers all bases.

We have a 1991 300-24 (don't mention EZLs) and a 1991 190D 2.5. Both run on MBs 5W30 Diesel spec synthetic. Why? Because it's dead cheap (£3 a litre from MB in the UK) and appears carry the right spec.

Our ambient temperatures range from -10C to +40C. We use the same oil year in year out.

My 300 has had that diet for my 20+ years' ownership. It's at 450k Kms and all seems well. Oil is changed at least every 12k Kms.

My son's 190D 2.5 came to him 14 months ago with 220k Kms and 10W40 semi. It was clicking in the valve area - hydraulic tappets. He started a program of frequent oil changes (8k Kms - ish) and clicking is dramatically reduced. He tried a can of Wynns (I think) additive and it MAY have made a minor improvement in clicking - I'm not convinced. He's done a "post Wynns" oil change and clicking is now much reduced. He has one minor leak at the top of the rocker cover but that was there when he got the car.

So, my conclusion is that, for a simple life, 5W30 Diesel seems to meet the needs, winter and summer.

If there are leaks, they should be fixed. I don't blame the oil.

And I don't buy into the "cars were designed for xWn semi back in the 80s" argument. That's all that was available. Oil technology has moved on and improved so there must be some gains, even for our old engines.

Just my 2c worth.

RayH

 

[AG129]

Where I live the temperature climbs to 50+ degrees Celsius in the summer. I use Mobil 1 FS X2 5W50 and I never saw such a low oil pressure in my 1991 500SL.

Most of the time the oil pressure floats over the 1 mark at idle in Drive. At the worst conditions and the hottest days it might drop very slightly below 1, but nothing as severe as your image.

When I used to use Mobil 1 0W40, it would drop a bit more but still not as much as your picture suggests.

This is in reference to the very first post, for some reason I wasn't able to quote him.

 

[MAVA]

This one is for stupidity, I know where Bill (WLB50) lives and have traveled those same streets many times, and my cars have exhibited " zero pressure " too with that 0W40. Common Sense says zero-pressure is no good no mater how it is sliced-up. AKA.... it less oil flowing through "System". Same thing in the Human Body..

Really, maybe "Our Stops" are........... longer as I see scenes of other places in the world where people do not stop at ALL. Maybe that is it......... I know California has the worst traffic in the world at many fronts..

Orrrrr All you guys have built a CRUST along the cylinder walls/piston/rings. We out here in the Western USA have not achieved that yet, or our oil -0W40(yes negative to give us no oil pressure). By result IT DOES NOT WORK FOR US here...

Martin

 

[sushipaste]

This one is for stupidity, I know where Bill (WLB50) lives and have traveled those same streets many times, and my cars have exhibited " zero pressure " too with that 0W40. Common Sense says zero-pressure is no good no mater how it is sliced-up. AKA.... it less oil flowing through "System". Same thing in the Human Body..

Really, maybe "Our Stops" are........... longer as I see scenes of other places in the world where people do not stop at ALL. Maybe that is it......... I know California has the worst traffic in the world at many fronts..

Orrrrr All you guys have built a CRUST along the cylinder walls/piston/rings. We out here in the Western USA have not achieved that yet, or our oil -0W40(yes negative to give us no oil pressure). By result IT DOES NOT WORK FOR US here...

Martin

Is it true that we should be using 5w-40 for socal weather? I’m currently running 0w-40..

 

[Josh]

When I my grandfather gave me the Durango and I took over doing all the maintenance myself, I noticed from the meticulous records he kept that the dealer used 5W30 as opposed to 10W30. It never gets cold enough in NW FL to justify 5W30, but I've stuck with it as the environmental conditions in the winter are similar here. Given the extreme heat here, 15W40 may actually be a better choice to transition too, as temps do tend to exceed 40°C.

 

[FATHERTIME]

Is it true that we should be using 5w-40 for socal weather? I’m currently running 0w-40..

If all you do is go to the market and work maybe it's ok but if like me with WOT at every stop light and long desert trips I'd sure change and avoid the 10k dealer recommend oil change intervals too. 20w-50 is what I have in all my SL's no problems. I go to Tahoe in winter also.