Happy Friday MBWorld family! I need your help and opinions on my current situation. Just as a disclaimer I am not accusing anyone of anything, I am just relaying the facts and trying to figure out what happened and who/what is responsible for the issue.

I took my car - 2009 C63 @ 95K miles - to shop this week for the following work:

1- Replace a failed oil temperature sensor
2- Replace a failed power steering reservoir
3- Install carbon fiber diffuser

I pick up the car the following day. I pay, get my keys from the mechanic and drive the car 50 feet forward (still on the shops property) so I can take some pics of the back end of the car in the sunlight with the newly installed diffuser. This detail is important you will understand why. The mechanic is 25 miles from my house. On the drive home, the new oil temperature sensor is working perfectly and the steering is smooth, finally no more annoying loud whining noise. Feeling great about everything and don't feel anything odd during the drive or notice any issues with the car.

I arrive home, find a parking spot on the street, drive forwards and inwards towards the curb then reverse into the spot straightening out the car. When I get out and start walking forwards towards my building I notice a leak of some sort in the same path I followed when parking the car. I follow it and surely it's coming from underneath my car. I look underneath the car to see exactly where its coming from and it's leaking from the front right side of the car, like 6 inches or so inwards from where the front right wheel is located. Within a few second of noticing the leak, it turns into a huge puddle of liquid underneath the car that's trickling down the street. I touch the liquid to try and figure out what it is and all I know is it's a brown oily substance. I am too scared to turn the car on and cause any damage to the engine in case the liquid that just leaked is motor oil. Anyhow, I call my mechanic and tell him what happened and he asks me "Did you hit anything on your drive home?" to which I respond with "No, there was nothing out of the ordinary about my drive home, I did not hit anything." He tells me it might be a gasket or line that needs to be replaced and tells me to get the car towed back to his shop. I call and schedule a tow truck to pick up the car on the 28th to take it back to the shop. After letting the car sit for an hour, I check the coolant reservoir which is on the same side of the leak and my coolant level is normal, no signs of coolant loss. I'm now thinking this is either motor oil or power steering fluid. Shortly after, I'm telling my friend about the whole situation and then pull my phone out to show him pics of the diffuser that I took while still on the mechanics property. When looking closely at the pictures, I notice a leak in the pictures! Which confirms that it was leaking before I even left the shop but unfortunately, I didn't notice it then.

Now that you have all the details, my question is what/who could be responsible for this huge leak. Could it just be coincidence or could this be something the mechanic forgot to reconnect properly or damaged while replacing the oil temperature sensor and power steering reservoir? If there are any mechanics on here that could tell me if there are any lines or gaskets or parts that are required to be disconnected then reconnected as part of completing an oil temperature sensor and power steering reservoir replacement, that may have caused this, it would be very helpful. The timing of events here is just making me question the whole situation. I'm trying to figure out what happened and not jump to any conclusions. Any help would greatly be appreciated. What do you think the issue is? Thank you all for your time and patience while reading this!

Looking forward to hearing your thoughts and suggestions.

 

Yes the lines from the engine oil to the cooler go on the passenger side and the thermostat change requires you to remove one of these... likely the issue of the leak.. as you said something got damaged or incorrectly reinstalled if that is the fluid being leaked. Did you pull the dip stick to check how low the oil is ?

 

Hey deadlyvt thank you for taking the time to help me figure this out, I really appreciate it. This is very helpful and informative and thanks for the suggestion as well. I'll check the oil level in the morning to get a good read. Assuming this is in fact the cause of the leak, is there a risk of further damage depending on what engine components the oil leaked on as it poured out? Or is it likely to just burn off and eventually dry? Does it need to be thoroughly cleaned or just replace the hose and top off oil?

Thanks

 

I agree with deadlyvt's comment. Check the engine oil level. Regardless of what the level is (probably low), I would not turn on the engine and certainly not drive around. After getting the leak identified and repaired, a thorough clean of the area and most probably the underside of the chassis is in order.

 

Hey DRBC43AMG thank you for your reply and advice as well, I really appreciate it. I will post an update tomorrow on the oil level. Will a thorough cleaning of the area and the underside of the chassis require removal of the skid plates and any other components? Also, is there potential for any further damage as a result of this leak? Lastly, do you think this occurred due to an oversight on the mechanics part during the repair process? If so, is this something the mechanic shop should honor at no further cost to me?

Thanks for your help!

 

Why look for who´s to blame?
Just fix it and enjoy it! =)

If starting to leak just when parking it it should have taken no damage.

 

I think the OP mentioned spotting oil drips/spots on the ground when he took a photo of the rear diffuser, but seen when viewing the photo later.
To the OP I would insist being present when the mechanic starts looking around the engine bay and underneath. That could give you the idea or proof of what's wrong.
Could be an oil line not tightened correctly, or reusing a old crush washer, or damaged cooler (hope not).

 

Hey swedepat, thank you for your response. Correct, there was no damage that occurred after I picked up the car. I noticed from my pictures that it was already leaking before I left the shop, so it was likely something that happened before I left with the car.

I'm not looking to blame anyone really, more so just trying to figure out what happened because if it was in fact the mechanics fault, that would be helpful to know as I would likely use a different mechanic going forward for any future repairs.

 

Hey DRBC43AMG, thanks for the advice. I agree, I would be more comfortable being present while they lift it up to inspect it. I'll certainly request that when I take it back in and I really hope its not the oil cooler.

UPDATE: I checked the oil this morning, took 5 measurements. The first few looked normal to me, but the last couple look a little low. It seems like my oil level is definitely low but not as low as I thought it would be based no the amount of liquid that leaked out, if the liquid is in fact motor oil. What are your thoughts on the pics below - oil leak or power steering fluid?


Oil read 1

Oil read 2

Oil read 3

Oil read 4

Oil read 5

I took this picture inside the engine bay where the leak is and I can spot some liquid at the bottom.

Here's a zoomed in pic of the same spot.

This is the power steering reservoir. For a newly replaced reservoir, I was surprised and concerned to see some type oil on it already - thoughts?

 

Are you wiping the dipstick off each time? If so that is an ok oil level and he’s the reservoir of new shouldn’t have fluid on it already did you check the level on that? In the picture that is showing the leak location I can’t spot where it’s coming from where abouts is the leak?

 

That underpan shape is right under the pulleys. My guess is the power steering reservoir was overfilled and is puking fluid, and/or it’s puking air out of the system through the top.

But if you were seeing oil pouring out (“huge puddle”) from in front of the passenger side front wheel, that’s likely oil thermostat related. Oil level looks fine though so it’s extremely unlikely (like zero) that you did any damage.

You may have two issues here.

 

Hey deadlyvt, yes I wiped the dipstick off before each measurement. I agree, the oil level seems ok to me, if anything maybe just a quart is needed to top it off but otherwise the level seems acceptable.

The picture that is showing the leak is taken on the right hand side, between the engine block and the coolant reservoir. Any thoughts? Does it seems like it's residue from the same leak or something unrelated altogether?

Agreed on the power steering reservoir, it shouldn't have any oil it considering it was newly replaced. I have not checked the oil level on that. I'm not sure how to - may you please guide me on how to check that? Probably an easy process, but would rather not guess under the current circumstances lol.

Thanks for your help

 

Hey BLKROKT thank you for your help and advice, I really appreciate it. I agree, an overfill might be the case with the power steering reservoir since it's already got some oil leaking out of the top. If this is the case, will it just purge the extra fluid and everything will return to normal? Deadlyvt also recommended to check the oil level on that and I asked him in my last response on how to go about checking that? If you can provide any guidance on that as well, that would be very helpful and appreciated.

That's a relief that it's extremely unlikely that I caused any damage as I'm also almost 100% certain I did not hit or run over anything that could cause damage. If it's oil thermostat related, any thoughts on what the possible issue(s) could be? Or is it impossible to tell based on the current symptoms until the car is lifted and inspected? I ran a search but wasn't able to find anything that offered any clarity.

Thanks for your help

 

yeah it’s super simple. Remove the front engine cover (it just pops out of clips by gently lifting on the sides of the cover. Then underneath you will see a cap on the power steering reservoir, upon removing the cap you will see a dipstick on the underside of said cap.

 

Thank you! I will check it out and post an update with the oil level reading.

 

UPDATE: I checked the power steering fluid level and I think its very low, the very bottom of the dipstick barely has some liquid on it. See pics below. Considering I just replaced the power steering reservoir, and the level is reading low, it seems like the fluid that leaked was power steering fluid. Would you all agree that this is likely the case since my motor oil and coolant fluid levels appear to be normal? Or is there still a possibility of the leak being any of the three fluids?

Considering all the information provided thus far, would you recommend I try turning on the car and/or driving it to the shop? Or is this risky? With a substantial amount of power steering fluid lost, is the car at risk of further damage if driven or is worst case scenario simply driving without power steering until the reservoir is refilled?

My apologies for the excessive questions, but I would like to thank you all for your patience and help, and I certainly learned a few things from you guys along the way which I really appreciate



Power steering fluid reading.

Zoomed in.

 

Don’t drive it. Get it towed.

 

Thanks BLKROKT - I agree, I think thats the safest thing to do. I'll provide an update when it's sorted out.