When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Engine oil HEAT EXCHANGER.... gasket only or unit itself is compromised.
Well played my friend. Now I'm assuming you don't mean the internal heat exchanger? Not familiar with the term (think you might be talking about what we call the radiator or intercooler in europe).
Well played my friend. Now I'm assuming you don't mean the internal heat exchanger? Not familiar with the term (think you might be talking about what we call the radiator or intercooler in europe).
Intercooler name is used for turbo, here it is just engine oil cooling... intercooling, yes.
This engine oil in coolant is not likely why you lost already so far 5 liters of coolant.
This is separate issue, just so happen it is happening now.
Good thing it is found out fast, it is surely "better" than coolant in oil.
Engine oil at minimum 1.5 BAR at idle is higher pressure than coolant, so oil in coolant happened if there is leak.
If found out too late, it can be coolant in oil instead.
Thanks to Cali's video link.....
I just realized MB diesel has the EGR cooler and fuel cooler. These 2 can leak too and 500K KM is a superb service life.
This engine oil in coolant is not likely why you lost already so far 5 liters of coolant.
This is separate issue, just so happen it is happening now.
Good thing it is found out fast, it is surely "better" than coolant in oil.
Engine oil at minimum 1.5 BAR at idle is higher pressure than coolant, so oil in coolant happened if there is leak.
If found out too late, it can be coolant in oil instead.
Thanks to Cali's video link.....
I just realized MB diesel has the EGR cooler and fuel cooler. These 2 can leak too and 500K KM is a superb service life.
Still, a proper 1.3BAR pressure test I am sure would find these leaks.
You are right. A pressure test should've picked this up if the mechanic knew what he was doing. I have learned that, when working on a Mercedes, if you want something done right, you should do it yourself. Only then can you be 100% sure something has been tested.
After filling up the coolant, there is now a leak at the bottom of the car. In fact, there are stains which initially looked like oil stains on the bottom engine trays, but now I know that the oil is in the coolant, it makes sense.
I suspect the fuel filter housing - I am going to check tomorrow.
You are right... I have learned that, when working on a Mercedes, if you want something done right, you should do it yourself.
Only then can you be 100% sure something has been tested.
I'll have to agree, you've got that right on: when you want something bad, roll up your sleaves !👍
You use not have any oil in the coolant tank when you started searching for coolant, true?
When the Benz coolant circuit is over pressurizedduring test, there's a good chance to blow the tiny heat exchanger gasket. That's still better than blowing the exchanger or head gasket, right?
🤪
I'll have to agree, you've got that right on: when you want something bad, roll up your sleaves !👍
You use not have any oil in the coolant tank when you started searching for coolant, true?
When the Benz coolant circuit is over pressurizedduring test, there's a good chance to blow the tiny heat exchanger gasket. That's still better than blowing the exchanger or head gasket, right?
🤪
I believe the tank was actually empty for quite some time, and I was driving on it. But I am not sure about this so I must assume its been empty for a months.
I'm not fussed if I need to replace the exchanger to be honest - just as long as that's the problem. If the gaskets fine, is the exchanger the only other part that can leak oil into the coolant?
I'm not fussed if I need to replace the exchanger to be honest - just as long as that's the problem. If the gaskets fine, is the exchanger the only other part that can leak oil into the coolant?
I am at a loss with OM651✌️
hopefully you can find what you're after
Last edited by CaliBenzDriver; Jul 14, 2022 at 12:16 AM.
Any oil cooler or heat exchanger or any cooling system can leak at gasket or its metal cores/tubes or supporting plastic components.
Making test flange can help if the shape is easy to make and you do not want coolant to enter oil system.
With test flange you can test suspect component on the bench, not while installed in a car.
More work for sure.....
UPDATE:
I mistakenly assumed it was oil in the coolant as it is a brown colour. However, after a simple google search of 'brown engine coolant', many seem to be suggesting that its dirty coolant from rust/corrosion/grime. i.e. a poorly maintained system. My coolant is very similar to the image below. If there is corrosion, a head gasket leak is still not ruled out, however since there are no other symptoms (milky oil, white smoke etc) I'm first going to be flushing, cleaning and refilling the coolant system. If the problem prevails, I will then look to the head gasket.
Thank you to everyone for your help over the last week. I may have burnt a lot of time trying to find the issue, but I learnt so about the W212's HVAC, cooling system etc in the process. Knowledge that will help me out a ton in the future.
You probably only owned the car recently.... that is why in my first post I asked, how much of the 500K KM is yours.
I want to know how much you know the car or the maintenance which has gone into the car.
==================================
I wrote : How long by mileage have you owned this car when you started "loosing" coolant ? Just in case you bought the car pre-owned.
===================================
The color of your coolant as seen on your photo is a scary one. Those are rust.
Why I said scary ? You lost 5 liters and now upon top up ( with distilled water or pre-mixed coolant ? ) the color is so rust infested.
W212 cooling system is approx 9 liters and if you already lost 50% and still have such rusty color assuming distilled water (colorless ) is the top up, I worry for you on the actual condition of the metals inside your cooling system.
From this long thread, it seems you do not know anything or enough of the previous owner/s maintenance program.
My logic is this :
01. Anyone who can keep a car running to 500K KM, I am sure have done good enough maintenance to make such mileage possible.
02. However, the rust color of the coolant is something not in line with proper maintenance.
It could be that you are a 3rd owner by now and the 2nd owner was not as loving towards the car as the 1st owner.
Or... the 1st owner have done his math on the expected cost to rejuvenate this car and gave up and sold the car, with a coolant loss condition , a hidden issue he never mentioned to you the 2nd owner.
Since original MB coolant is not cheap, he has been filling the cooling system with regular tap water and some tap water can be very unfriendly for a car cooling system.
This is what happen when MB Indonesia failed to pre-mix properly coolant % and poor quality water used for sure too.... to my car.
Older yellow/amber coolant used, damn by 2014 I think MB Germany or USA went blue coolant already. https://mbworld.org/forums/e-class-w...i-am-sure.html
If your cooling system metal has gone bad to the level of metal pitting, it is as bad as it can be. New gasket won't help.
Are there anymore hidden unpleasant surprises on your car ?
Probably more wear and tear issues are coming. 500K KM worth of wear and tear is something we can't avoid.
I hope I am wrong...........
You probably only owned the car recently.... that is why in my first post I asked, how much of the 500K KM is yours.
I want to know how much you know the car or the maintenance which has gone into the car.
==================================
I wrote : How long by mileage have you owned this car when you started "loosing" coolant ? Just in case you bought the car pre-owned.
===================================
The color of your coolant as seen on your photo is a scary one. Those are rust.
Why I said scary ? You lost 5 liters and now upon top up ( with distilled water or pre-mixed coolant ? ) the color is so rust infested.
W212 cooling system is approx 9 liters and if you already lost 50% and still have such rusty color assuming distilled water (colorless ) is the top up, I worry for you on the actual condition of the metals inside your cooling system.
From this long thread, it seems you do not know anything or enough of the previous owner/s maintenance program.
My logic is this :
01. Anyone who can keep a car running to 500K KM, I am sure have done good enough maintenance to make such mileage possible.
02. However, the rust color of the coolant is something not in line with proper maintenance.
It could be that you are a 3rd owner by now and the 2nd owner was not as loving towards the car as the 1st owner.
Or... the 1st owner have done his math on the expected cost to rejuvenate this car and gave up and sold the car, with a coolant loss condition , a hidden issue he never mentioned to you the 2nd owner.
Since original MB coolant is not cheap, he has been filling the cooling system with regular tap water and some tap water can be very unfriendly for a car cooling system.
This is what happen when MB Indonesia failed to pre-mix properly coolant % and poor quality water used for sure too.... to my car.
Older yellow/amber coolant used, damn by 2014 I think MB Germany or USA went blue coolant already. https://mbworld.org/forums/e-class-w...i-am-sure.html
If your cooling system metal has gone bad to the level of metal pitting, it is as bad as it can be. New gasket won't help.
Are there anymore hidden unpleasant surprises on your car ?
Probably more wear and tear issues are coming. 500K KM worth of wear and tear is something we can't avoid.
I hope I am wrong...........
You are right. But there is no point panicking until we flush the entire system. After a flush, we will see if the rust comes back.
True enough, A thorough flush and check again next weekend, may need two, but one may do it! Maintain that positive attitude!
what were you suggesting in the above post? Corrosion so bad the engine is beyond repair?
you may still be right. I've just inspected a coolant hose and the corrosion build up is bad.
what were you suggesting in the above post? Corrosion so bad the engine is beyond repair?
you may still be right. I've just inspected a coolant hose and the corrosion build up is bad.
what were you suggesting in the above post? Corrosion so bad the engine is beyond repair?
you may still be right. I've just inspected a coolant hose and the corrosion build up is bad.
I was suggesting that if that was the color of the coolant, it was likely tap water was used or coolant was way past it's usable life and rust had taken over, OR the incorrect type of coolant was used which caused the rust to proliferate at a increased rate.
My '12 had the original coolant for 8 years, with 24k miles of usage, so very little and it came out looking just like what I replaced it with. My '13 was changed at 6 years 65k miles, it was a little dirty but mostly was just a little "cloudier" I might use some radiator flush product to help clean the system out, then run some distilled water with some coolant, about half the normal 50-50 mix then see how it looks before filling it with the correct coolant mix, I have had luck with the flush products on other cars.
Last edited by pierrejoliat; Jul 16, 2022 at 09:55 AM.
I was suggesting that if that was the color of the coolant, it was likely tap water was used or coolant was way past it's usable life and rust had taken over, OR the incorrect type of coolant was used which caused the rust to proliferate at a increased rate.
My '12 had the original coolant for 8 years, with 24k miles of usage, so very little and it came out looking just like what I replaced it with. My '13 was changed at 6 years 65k miles, it was a little dirty but mostly was just a little "cloudier" I might use some radiator flush product to help clean the system out, then run some distilled water with some coolant, about half the normal 50-50 mix then see how it looks before filling it with the correct coolant mix, I have had luck with the flush products on other cars.
Good news. Coolant flush done and it was fine; blue without any trace of rust. However, only about 3-4 litres came out, and I understand the system takes up to 10 litres. My guess is there was more coolant being used as the weather got hot and there was no leak in the first place.
Good news. Coolant flush done and it was fine; blue without any trace of rust. However, only about 3-4 litres came out, and I understand the system takes up to 10 litres. My guess is there was more coolant being used as the weather got hot and there was no leak in the first place.
Hi did you ever get to the bottom of this.
My w212 I have to top mine up the engine coolant every 4 weeks.
The colour is exactly the same. Car bought from new, serviced each year on time.
220km on it now.
Mercedes SLR McLaren 722 S Is Extremely Rare Example Modified by McLaren
Slideshow: A one-of-one U.S.-spec Mercedes-Benz SLR McLaren Roadster became even rarer after a factory-backed transformation at McLaren's headquarters.
Engine coolant
