Coolant leak




Out to the dealer it goes.....
Under the thermostat.




Inflation just tripled the price in labor, for $100 dollars worth of parts SMH.
If I don't part out the car first, I may see you guys only in the W213 forums for a while.




Inflation just tripled the price in labor, for $100 dollars worth of parts SMH.
If I don't part out the car first, I may see you guys only in the W213 forums for a while.




In your M278 these coolants lines are like below ?
https://www.ebay.com/itm/25549359962...8AAOSwIMJiXHze


If so, that means the plastic portion is the broken/leaky one...yes ?
Probably the same engine as yours ?
Last edited by S-Prihadi; Jul 21, 2022 at 12:53 AM. Reason: add info




I believe they have improved radiator stop-leak as time has passed, I don't think it clogs things up as bad as it used to, much as I hate to suggest that, one must sadly do a realistic cost benefit analysis. I have a suggestion, my daughter was looking at a huge repair bill for a similar issue, she ended up taking it to a local technical high school, it worked out well and she paid 25% of the dealer estimate.
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mixed plastic + metal conduits
Can you patch a section of rubber coolant hose to replace the brital plastic section? It looks like there is a 1" overlap at each end for a tight grab.
metal + rubber coolant line 👍
Last edited by CaliBenzDriver; Jul 21, 2022 at 05:39 PM.
The Best of Mercedes & AMG
On the other hand, "it's just a small pipe". I see this as DIY-able, acknowledging alot of time is involved.
Regarding a repair to the pipe, this would be temporary at best, I would DIY replace it if this was my vehicle.









=== Update ===
For references to plastic and rubber under high temperatures
https://www.martins-rubber.co.uk/blo...ber-materials/
https://www.craftechind.com/heat-resistant-plastics/
Last edited by JCM_MB; Jul 21, 2022 at 09:25 PM.




Perhaps plastic is able to take more heat for a while than heater core/radiator flexible hose






In homes, they use a plastic serpentine hose to heat cold floors on East coast. It has a layer of aluminum pipe embedded within the plastic tubing.
It makes sense to have a flexible insert of rubber to allow for expension and alignment of the metal pipes. Once plastic gets hard, stress relief cracks develop
Last edited by CaliBenzDriver; Jul 21, 2022 at 09:31 PM.
It is definitely not rocket science, nor need for special tolerances/measuring. But the ability to rebuild the puzzle afterward.
What do you think will be the weak point of patching with a hose? Pressure range? Thermal wear on the hose? Certainly, it already is a maintenance item, i.e. to be replaced after a certain mileage. I see it possible as a quick recurrent cheap fix. Say replace the hose segment every other oil change (along with the O-ring anyways).
I wouldn't waste time with a repair. Replace the leaking tube and do it right.




=====================
I just read this unique information on M278. Some have separate aftercooler coolant recovery bottle some doesn't.
https://www.benzworld.org/threads/m2...rvoir.3081144/
So when troubleshooting coolant leak, observe this information accordingly if cross sharing of cooling lines exist.
If only a single coolant recovery bottle....it can only mean sharing of cooling facility between aftercooler and engine.
For M276 3.0 Turbo it is easy.
Aftercooler is totally a stand alone coolant circuit with its own coolant reservoir bottle , so leak here has nothing to do with engine cooling.




:1 - Disconnect the engine from the surrounding
2 - Lower the sub-frame+engine assembly
3 - Replace cooling lines
4 - Push-up the sub-frame+engine assembly back
5 - Reconnect the engine
6 - Refill fluids
7 - Notify the customer in the waiting area.
I assume the engine out procedure is standard, and it is based on the customer can afford it.




:1 - Disconnect the engine from the surrounding
2 - Lower the sub-frame+engine assembly
3 - Replace cooling lines
4 - Push-up the sub-frame+engine assembly back
5 - Reconnect the engine
6 - Refill fluids
7 - Notify the customer in the waiting area.
I assume the engine out procedure is standard, and it is based on the customer can afford it.
5 minute job instant=$3000k labor.
Nah, this is becoming normal, and someone is bound to make a better part. All aluminum would be best. Just going to wait until enough S550's and CLS550's go thru this, and MB or the aftermarket will take action. Not going to replace crap with the same crap.
@S-prihadi yes those are the lines.




The very same reason I compiled my 10 year rejunevation plan. Sell car at 10 years old or do the "expensive" list and keep the car to at least 15 years of age. June 2024 is E400 10th year.
What I seen on M278.
Soon there will be issues on these :
01. Heater plastic pipe from rear of engine to firewall to heater core of HVAC.
Y16/2 Heating system shutoff valve.
02. Thermostat and its plastic housing. Same as M157
https://www.ebay.com/itm/353377977026
I think being turbocharged and if we drive agressive, we aged these plastic/rubber faster than gentle drivers on non turbocharged engines.
Fun and heavy throttle foot has its cost

If engine out is what needed to be done and if the car is intended to be kept to say 15 years old, start looking at every plastic/rubber ( should be plenty ) which handle coolant or oil and replace them all.
Engine mounts on M278 seems a pain to remove, so while engine out, replace them.

Someone with some machining skills could make a few bucks for sure.




One day the coolant hose from engine to heater core had a tear.
I lost coolant and managed to avoid cylinder head warping overheat by some luck.
Why I did not call a tow truck was because the area I was at is not safe, so I keep filling the reservoir with water at intervals and managed to drive home.
The stupid Fiesta has no coolant temp gauge, only OVERHEAT warning when overheat occured.
The overheat was so bad, even my low engine oil pressure lights up due to thinning of the oil I think. At least Fiesta has Low Oil Pressure warning unlike my MB

Anyway. I replaced every damn plastic and hoses on the car, including a new radiator which is plastic on its sides.
Some hoses plastic ones when removed, the crumbled down like dust...insane.
All brake hoses also replaced.
I paid a lot, US$3.5K to replaced those plastic/rubber worries and do some repair on the tranny shift bearing
The car used value was only US$4.5K in 2021 when all these occured.
I wanted to keep it for 5 more years....so I thought.
When all good, the ABS light pops out 1,000KM later. This ABS module locally caused US$800 or so.
I got sick of the car and I sold it off.
Lucky new owner, he only needs to buy ABS module and the rest of the car and its plastic/rubber worries are gone.
I envy quality marine diesel engines, no plastic parts.
Yes, hoses we change at 10 years, but very few hoses compared to a car engine which has lots of "accesories".
Plastic and rubber failing is a matter of WHEN and not IF.
M278 being bigger in size is more complex than my M276.
Seeing my turbo coolant hose is not designed as stupid as M278, there is still a plastic end but not at engine block....LOL.
Item 40 is where plastic end is used.
I am 2 years away to the car 10th Bday and I am already have the rejuvenation plan/list.
I think US$10K will be exceeded in parts and labor, and the E400 by 10th year value would worth at best US$24,000 in 2024. Now it is still worth true market wise approx US$33K but the tax book
charged me road tax based on insane US$53K x 2.1% per year.
If I go thru with my keep for at least 15 years PLAN, the only reason is because cars are downsizing in engine capacity and I want minimum 3 liter. Indonesia ADDITIONAL luxury tax is based on engine displacement.
I can't afford the E63 W213 AMG big engine version, in fact even if I have the money, I wont buy engine with freaking turbos at the hot middle of the V bank ( M176 / M177/ M178 ), no way for my climate and traffic jam.
















Sure it had a rock chip, but it had been there for a while.