Oil Sensor question ?? Gilly.. ?? Anyone ??
 

I have a question on a the FSS oil sensor. Here is the problem. I have 95,000+ on the ol' ML (1998). I recently ( within the last week ) I have had a weird oil light problem. The vehicle is full of 0W-40 Mobile 1. The oil was changed approx 5000 miles ago and the FSS was reset to the 10,000 miles. I drive approx 45 miles each way to work. On the trip to work ( still dark out and less than 70 degrees ) the Oil DOES NOT come on. However on the trip home at approx mile 38 from work ( mid afternoon, temp approx 78-82, sun shining) I get an indicator "BEEP" and the oil light comes on. It goes out after a few minutes and is off for a few minutes, then comes on again. and this cycle repeats the rest of the trip home. Car is parked, and then again the next day the Oil light is again off and doesn't activate on the way to work, but does on the way home again. Also the FSS indicator went "down" to 7200 miles and since the oil light has had these occurances the FSS indicator now says 9200 miles. At this rate based on the FSS, I may never have to do an oil change again, since I expect that by tomorrow it will say that I have 10,000+ miles to go ;). But seriously, where is the oil sensor, and is it relativly easy to replace, As it seems that I will be adding this to my list of parts replaced. What exactly does the oil sensor measure ??.
Thanks

The first thing i would do is to do an oil consumption test. The oil sensor going bad is a possibility, but you may be experiencing a true oil loss issue.

What you should do is to wait 20 mins after shutting down the engine and doing an oil level check with the dipstick.

You should wait a mininimum of 20 mins to do this test!

If your dipstick level is staying the same, then you have an oil sensor problem. If your dipstick level indicates a drop in less than 2,000 miles then you have an oil burning problem and you should see your dealer as you may qualify for a ring/valve job under warranty

Good luck

Oil sensor
 

It uses almost zero oil. It typically uses approx 1/2 quart between FSS oil changes. I have been changing by the FSS +or- 1000 miles since new with Mobil1 0-40. The vehicle never even "puffs" a bit of smoke during startup. The oil level is exactly at the line indicating full which is where I filled it to at the last oil change approx 5000 miles ago. I did have one time about 3 years ago that I had gotten an oil change at the dealer and they filled it to just above the "low" mark and I went on a 1700 mile trip. While going down a very steep mountin trail at about 10 miles an hour the oil light came on. I "freaked" thinking it was "oil pressure" and immediatly shut off the engine. ( and read the manual) When I read that it was oil level, I just continued my trip to town and threw in a quart of 15W50 mobil 1 and continued my trip without incident.

Since the oil light has been activating, I have been checking the oil level before starting each morning.

I was "hoping" that it was just down a quart of oil.

What is the warning you are getting specifically?

Gilly

Oil sensor
 

As described in the first post. I am driving home @ approx 85MPH ( hot weather - South Florida ) (the vehilce is normally driven @ 75-90 MPH since thats the flow of traffic speed on the turnpike / expressways here) and get to about mile 35 from work when i get a single "beep" and the "oil can" light comes on. It (the light)remains on for approx 1 mile (35 seconds) and then goes off. Again approx 1 mile later the same thing happens. However the next morning, all is well and I have driven over 90 miles some mornings without the light/beep happening.

I am going to order a sensor and replace it this week, where is the sensor located? , and do I need to drain the oil to replace it. I suppose I will just do a complete oil change as I have a few cases of 0w40 and filters.

Yes, the lower oil pan cover needs to be removed it's inside the crankcase bolted to the upper part of the pan. You will need to obtain some Loctite 5900 to reseal the pan, can't use anything else. It will need to set-up for a couple hours before you can refill the crankcase. It's a bear to get the lower pan on and off on an ML.

Gilly

oil sensor
 

Ouch,

I figured it would be and externally attached device. Well I have rebuilt some hot rod engines, but I don't see my self pulling the oil pan on my daily driver truck. Looks like I'll just change the oil every 10,000 miles based on milage from now on and "stand by" for trading the vehicle when the next item fails or needs repair. Is this item failing going to take another component with it. It seems that everything is so tied together in this vehicle it makes me wonder.

Thanks for the info.

No, it should be fine.
There is a part that the electrical harness connects to that passes through the upper oil pan section, over on the right side of the engine, that's how the sensor "connects" to the rest of the vehicle.
One thing i wonder about is that if you are getting the amber "oil can" light in the cluster, you typically get a message in the odometer section saying "lo oiL" or "HI oiL" with something else like +1.0L or -1.0L or like that. MB has this engine, and most of their engines, set up so the proper amount of oil in the crankcase will give a dipstick reading in the middle of the operating range. Possibly your oil level monitor is reading too much oil after the engine warms up. With an oil change, you should put in 8.5 quarts of oil in it, not 9, it's very picky.

Gilly

Oil sensor replacement ??
 

I am now getting the 2.0L errror when the "oil can" light comes on. The vehicle is not low on oil. Also the milage till FSS keeps going up. It started at 10,000 but now is 11,800. Not bad, I may never have to change oil again :). So I believe that I must brake down and swap out the Oil sensor.

My questions are
Does anyone know the torque of the oil pan bolts?

Torque of the oil sensor bolts ?

Type of sealer for the oil pan, or does it use a gasket.

Use Loctite 5900 as the sealer for the pan, that I know for sure, Accept NO Substitutes!!!

Torque on the bolts I believe are all 20 nm.

It's a tough job, it's hard to get the pan out from between the engine and subframe. It helps to be able to slightly lift the engine to do the job, but is doable without this effort.

Gilly

Oilo sensor replaced and dipstick view
 

Thanks

I broke down and replaced the oil sensor. List for 67.00 but threw down a business CC and got it for $53.00 @ the local dealership. Over my years of buying car parts (at dealerships and parts houses) I never "take" the first quoted price. I'm not sure why shops get parts so much cheaper than individuals, but its always negotable, even at the Pep Boys. Hey a few bucks is a few bucks.

The new design is much different than the original 1998 version. There is NO WAY with the new one to get the oil pan on with the unit in. I ended up jacking the engine up approx 1/4 inch and all was well.

For anyone who is curious what the engine looks like from the oil pan I attached few pictures. The Dipstick tube is visable and shows how it sits in relation to the bottom of the pan. The item by the dipstick tube is the oil sensor.


Whole job ( minus the overnight for the sealer to cure ) was 2 hrs, including replacing the oil filter.

Anyone thinking of doing this job, I recommend that you put the oil pan sealer on the engine block and not the oil pan.

Also remove the bracket for for the transmiision cooler lines from the crossmember and push the cooler lines out of the way. They have plenty of slack.

excellent
 

Technical posts are what keep me coming back.

Thanks Guys!!

Help!
 

My '98 ML320 had the same oil sensor issues described above. I had to loosen the right hand engine mount and lift the engine, but I did manage to get the pan off. The new sensor has a white cap on top. I assume I am to leave this on the sensor? Looks easy to remove, like perhaps it's only there to protect the sensor during shipping?

Also, the 5900 sealant (has M-B packaging, from the Parts Bin), has no nozzle. For 15 bucks am I expecting too much to think a nozzle should come with it? I guess I'll drill a 2mm hole in the end and have at it.

Can you post a photo?

Photos of new sensor...