Oil in coolant and coming from back of engine?

[WillElZiBub]

Hello all, I'm new here.

Got a W203 C class 220CDI Estate, automatic.

Gear changes got clunky about a month ago and oil appeared in coolant.

Immediately drove home and changed the oil cooler, on the engine.

However, first drive after this, and it's not the oil cooler.

There's now a real struggle to change gear, obvious gearbox whine, masses of oil in the new coolant, and there is now loads of coolant pouring from the back of the engine area.

Any idea what this might be?

Here are two videos;

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As you can see in the second one, there's an obvious coolant leak of grey oil/coolant mix from the back of the engine/bell housing area

Thanks for any advice in advance

 

[DSM10000]

The transmission cooler is incorporated into the engine coolant radiator.

It was quite common in early W203 vehicles with Valeo radiators that failure due to corrosion could cause engine coolant and transmission fluid to mix leading to gearbox problems and gearbox failure.
A replacement radiator /transmission cooler and a comprehensive flush of the transmission may save it but in all liklihood the transmission may be damaged beyond repair.

 

[BigJase88]

Yeah that transmission sounds terminal

 

[WillElZiBub]

If I replace the radiator, flush out the gearbox and put in new ATF, will the whining go and the box be saved?

 

[DSM10000]

If I replace the radiator, flush out the gearbox and put in new ATF, will the whining go and the box be saved?

How do you expect me or anyone else to answer that?

I would strongly suggest that you take the car to someone who specialises in MB vehicles.

Changing the transmission fluid can be difficult. The bolts holding on the drain pan will probably be seized and may break off requiring accurate drilling out.

You must ensure that you use the correct ATF and also replace the filter

Search on the Forum. There is a "How to" post with detailed information on the 5 speed gearbox fluid change procedure.

 

[WillElZiBub]

The transmission cooler is incorporated into the engine coolant radiator.

It was quite common in early W203 vehicles with Valeo radiators that failure due to corrosion could cause engine coolant and transmission fluid to mix leading to gearbox problems and gearbox failure.
A replacement radiator /transmission cooler and a comprehensive flush of the transmission may save it but in all liklihood the transmission may be damaged beyond repair.

It's gutting because if I'd have known this I'd have changed the radiator when I bought the car.

I've done over 70k miles in this car in the past 3 years, I feel I've had a lot out of it really, but I'd rather fix than replace.

 

[johnsco]

These transmissions are complex and incorporate an electrical plate, as well as critical friction surfaces in the clutch-packs.
You can give it a try, but I fear that the transmission will be ruined.
Replace the rad and make sure that the pipework is flushed out.
Regarding the box - I fear that the answer will be to replace.

 

[WillElZiBub]

How do you expect me or anyone else to answer that?

I would strongly suggest that you take the car to someone who specialises in MB vehicles.

Changing the transmission fluid can be difficult. The bolts holding on the drain pan will probably be seized and may break off requiring accurate drilling out.

You must ensure that you use the correct ATF and also replace the filter

Search on the Forum. There is a "How to" post with detailed information on the 5 speed gearbox fluid change procedure.

Thanks, I'll see what I can find.

 

[johnsco]

You were not to know about the Valeo radiator story that has plagued a number of MBs for some years.
I've owned a number of MBs over the years ...... I must admit that I've never once checked on the make of the rad.

 

[Petrol Pete]

The 722.6 transmission in your car is one of the most robust out there . My 5.4 V8 AMG C55 has the same (give or take a few minor differences) transmission. simple to service and replacement parts widely and cheaply available , it's used in all sorts of things including buses , trucks and V12 Mercedes Benz.

But . once it has had a good drink of coolant due to a faulty Valeo cooler it's usually toast.

Repairable ? yes , but rarely worth it , used ones are easily obtainable .

 

[Petrol Pete]

Have a quick skim through this , it will show why you do not want coolant in this transmission.

NAG 72.6 rebuild video | Engine

722.6 for anyone who is curious .

forums.mbclub.co.uk

 

[WillElZiBub]

Have a quick skim through this , it will show why you do not want coolant in this transmission.

NAG 72.6 rebuild video | Engine

722.6 for anyone who is curious .

forums.mbclub.co.uk

That video is over 90 mins long - although any auto box is very complicated he doesn't say why coolant can't be drained out and replaced with fresh ATF?

Tbh there was probably no coolant in my car, it seems there was only ever water in there.

I replaced the water pump 6 months ago and as it was the hottest summer ever I only put water in.

I can imagine that's possibly what's rotted the inside of the radiator, but hopefully as there was no/very little glycol in there the box should be ok...?

 

[WillElZiBub]

The 722.6 transmission in your car is one of the most robust out there . My 5.4 V8 AMG C55 has the same (give or take a few minor differences) transmission. simple to service and replacement parts widely and cheaply available , it's used in all sorts of things including buses , trucks and V12 Mercedes Benz.

But . once it has had a good drink of coolant due to a faulty Valeo cooler it's usually toast.

Repairable ? yes , but rarely worth it , used ones are easily obtainable .

Do you mean a used tranny or just buy another car?

Where would I get a used tranny from, and how difficult is it to fit?

I'm guessing fitting a new gearbox is serious work?

 

[Petrol Pete]

That video is over 90 mins long - although any auto box is very complicated he doesn't say why coolant can't be drained out and replaced with fresh ATF?

Tbh there was probably no coolant in my car, it seems there was only ever water in there.

I replaced the water pump 6 months ago and as it was the hottest summer ever I only put water in.

I can imagine that's possibly what's rotted the inside of the radiator, but hopefully as there was no/very little glycol in there the box should be ok...?

I thought it might be self explanatory . just imagine a complex unit designed to function only on one very very specific type of fluid then having glycol and water introduced to it.

Everything you see in this video swims in ATF , including all of the electrical items , there are scores of clutch plates and bearings that need only one type of fluid to function. Engine coolant is not that fluid . The friction surfaces of the clutch plates 'age' over time to the point where on some (not this) transmission replacing all of the ATF at once is not reccommended .

Have a go at 'flushing it out' , and I really hope that works for you , but remember just changing the ATF and filter will still leave a litre or so of fluid in the box unless your transmission has a drain plug on the TC (many 722.6 TC's do not have a drain plug) so you would need to have this done by someone who knows how to flush the whole system including the cooling lines and TC , multiple times .

As an aside , running any modern engine (long term) on just tap water as a cooling medium is a recipe for disaster.

As for your question on fitting a new transmission , it's actually not that difficult with the correct tools and a lift. Whether it is cost effective for you is another matter.

You are new here (welcome) and have come to the right place for answers. Let us know if you have more questions.

 

[WillElZiBub]

I thought it might be self explanatory . just imagine a complex unit designed to function only on one very very specific type of fluid then having glycol and water introduced to it.

Everything you see in this video swims in ATF , including all of the electrical items , there are scores of clutch plates and bearings that need only one type of fluid to function. Engine coolant is not that fluid . The friction surfaces of the clutch plates 'age' over time to the point where on some (not this) transmission replacing all of the ATF at once is not reccommended .

Have a go at 'flushing it out' , and I really hope that works for you , but remember just changing the ATF and filter will still leave a litre or so of fluid in the box unless your transmission has a drain plug on the TC (many 722.6 TC's do not have a drain plug) so you would need to have this done by someone who knows how to flush the whole system including the cooling lines and TC , multiple times .

As an aside , running any modern engine (long term) on just tap water as a cooling medium is a recipe for disaster.

As for your question on fitting a new transmission , it's actually not that difficult with the correct tools and a lift. Whether it is cost effective for you is another matter.

You are new here (welcome) and have come to the right place for answers. Let us know if you have more questions.

I've deffo learned about not using engine coolant properly

I'll try and tow the car to a nearby garage where they can hopefully clear all of the gunk out of the tranny and replace the radiator and ATF.

I love the car and hope it's fine.

We'll see.

 

[BigJase88]

Hold on a minute you put 100% water in as Coolant

You need to stop with the car DIY

I would guess something has frozen with the recent cold snap and cracked

 

[WillElZiBub]

Hold on a minute you put 100% water in as Coolant

You need to stop with the car DIY

If there was already coolant in when the water pump was changed, then a top up with water means there's still coolant in there.

Is this a forum where helpful advice is given (everyone else has been great) or one of those places where people point and laugh at people?

 

[markjay]

...Is this a forum where helpful advice is given (everyone else has been great) or one of those places where people point and laugh at people?

Like most Internet forums, it's a bit of both... though this particular forum has more of the former and less of the latter.

 

[Petrol Pete]

OP you are approaching a point where the repair will cost more than the car is worth , it's your call of course. W203 C class suffer rust issues most hidden from view and rusty hidden (very difficult to access) brake pipes (MOT failure point) so the costs can escalate.

As an aside my mate has just sent his van to recycle heaven by repeatedly ignoring a coolant leak and topping it up with tap water . The engine block split in two separate places, not sure why the 'freeze/welch plugs' did not pop first , maybe they don't exist anymore, same as his van.

It was an old Fiat doblo so no great loss.

Stay on here an we will give you help and advice and the occasional dig in the ribs but we generally mean well.

 

[DSM10000]

Do you mean a used tranny or just buy another car?

Where would I get a used tranny from, and how difficult is it to fit?

I'm guessing fitting a new gearbox is serious work?

I would strongly suggest not typing in the words "used tranny" into a search engine unless no one else uses that device