Hi all. I’ve got this 99 e320 that runs great, doesn’t leak a drop, never overheats. Grandmas beauty save for grandma hit a pole at the bank or something. Regular MB service up until 2018, then essentially parked. 72000 now. Got it from an estate sale.

A couple of weeks ago the coolant level light comes on. I check it out but the level looks only a tad low. I top it off and keep driving. The light goes off. Days go by, I’m looking around on the ground and under the hood for signs of a leak but nothing visible. I know I need to dive into but my plate is overflowing so I top it off again when it comes on a few days later, and again a few days later.

Yesterday a new light comes on - “oil sensor faulty”. This morning before going to work I think “I better check the oil” and I may have found where my coolant has gone :/ The oil cap has light brownish crap stuck to it. The dipstick pulls out with a thinned dark liquid that freely drips from it. It stinks a bit like gasoline as well.

I know head gasket is a possible cause. What are the others? Oil cooler? Injectors? Im trying to get my bearings so I know how bad I want to pursue getting it remedied.

Thanks in advance for any suggestions/advice.

Just don't jump to conclusions. I would bet small money that the coolant leak has nothing to do with your oil situation.The gunk under the oil cap is fairly normal, and if the coolant had gone into the oil you would have mayonase on the dip stick. It sounds like you may have gasoline in your oil. The plastic cover under the radiator can hold quite a lot of coolant.

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'97 E 300 D

The oil cap residue is normal and due to the car not being driven regularly or far enough to burn the moisture out of it. It is quite common on these with city drive cars.

Thanks for the responses!

What would cause the oil level to rise to the top of the plastic bobber on the dipstick? I did the last oil change myself (it’s due to be done again) and had it between min-max until this developed.

Also what are some potential causes of gas in the oil? Also a byproduct of short drives? I typically drive 10-15 minutes each way to work with about 5 minutes at 60-70mph and the rest around 40 mph.

Just realized I forgot one piece of the story - after the “oil sensor faulty” light, on the next short trip it read something like “oil above max level”

Bad injector leaking extra fuel into a cylinder?
Any spark plugs show signs of running rich?

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Rmasteller - I’ll look into it this weekend.

I’m not very familiar with this car - is there even an oil cooler on it?

No.

Well, it’s definitely coolant in the oil. I had a mechanic check it out and verify. I drove it back home and had the “Oil Quality!” Light come on. Also took a sample from the dipstick today - whatever foreign smell was gone. Just oil odor. A bit milky looking like lightly creamed coffee. I put it on a plate and couldn’t get it to ignite (no gasoline).

when was the engine oil changed on it? The oil sensor on the old W210s are a nifty piece of kit and measure oil quality for longevity too - thats why the car is specced to run 229.3 spec engine oils (they last upto 15,000 miles)

However the oil quality sensor will go to dumbtown if it was filled with Jiffy lube special oil which will gel out after 6000 miles of short trips.

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2012 BMW X5 (Beef + Granite suspension model)

1995 E300D - The original humming machine (consumed by Flood 2017)
2000 E320 - The evolution (consumed by flood 2017)

About 6000. With Mobil 1 0w-40

The usual "crosstalk" is from oil into coolant. Oil pressure is higher than coolant pressure. I'm having trouble understanding how coolant can show up in the oil - even if the car had an oil cooler - which the V-6 does not. Anybody actually seen this before?

coolant can show up in the oil by 3 paths.

1 is the coolant/oil heat exchanger which this car wont have as its US specced. The Euro spec ones had it with tow package.

2 - the headgasket sealing properties have breached due to some past event.

3 - someone accidently poured coolant into the oil fill hole.

First order would be to test cooling system integrity with a pressure tester.

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2012 BMW X5 (Beef + Granite suspension model)

1995 E300D - The original humming machine (consumed by Flood 2017)
2000 E320 - The evolution (consumed by flood 2017)

Well, #1 and #3 apparently aren't the case here. One thing the OP hasn't mentioned is if the coolant level is dropping. From what I can glean from his posts the oil level seems high by at least 1/2 quart - maybe more. That should should show up as a lower coolant level. Anyway, yes, the system needs to be pressure tested.

Thanks Vince. Paragraph 2 of the original post

“ A couple of weeks ago the coolant level light comes on. I check it out but the level looks only a tad low. I top it off and keep driving. The light goes off. Days go by, I’m looking around on the ground and under the hood for signs of a leak but nothing visible. I know I need to dive into but my plate is overflowing so I top it off again when it comes on a few days later, and again a few days later. ”

It’s leaking out and reappearing in the oil system.

I don’t have the time or money to have new gaskets/engine.

In addition to the above, I discovered that the front drivers side control arm is about to snap and send the wheel into the wheel well.

The car will be sold for parts or worst case donated to the local public radio station through the Car Talk program.

If someone is in the Midwest (US) and wants to make an offer, send me a pm please.