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Hi all. I'm from the UK and have a Weistec supercharged C63, and have an issue that my specialist does not seem to be able to solve and I would really appreciate some help since it seems like you guys are much more familiar with charged M156s and M156s in general. Basically, the coolant hose that goes into the water pump, that is secured with a circlip, keeps bursting off and spraying my engine bay with coolant and is obviously preventing me from driving the car.

When this first happened, I got a low coolant warning, shut the engine off and got the car recovered to the specialist who fitted the charger and who had done some other engine work for me at the same time including new head gaskets and head bolts. I noted that in the coolant tank, I could see some evidence of mixture of oil and water, some milky residue when trying to refill with water. Initially, they thought it was a head issue causing the coolant system to pressurise, so they took the heads off and sent them off for skimming, but they were fine so they were a bit stumped. When they went to refit the head, they said that 3 of the threads in the block were stripped and this was the cause of the issue? This did not make much sense to me, but I am not a mechanic and I trusted them. On this basis, the specialist offered to either have the block helicoiled or use a good block they had on the shelf so they could put the engine back together, and fix the issue. Since the car is non standard, they recommended going down the route of using the spare block (despite my understanding that helicoils would actually be stronger than the original threads). They put the car back together and I was assured everything was good, they had road tested for 100+ miles and the car drove fine. I went to pick up the car (having been at the specialist for 6 weeks at this point), drove the 100 or so miles home successfully, thought that was that and went on holiday.

Earlier today, having driven the car for the first time since driving home from the specialist, the same thing has happened again. I called the specialist and they said that it could be the hose was just not secured properly (some faith in their workmanship they have), and for me to try reconnect it. I managed to do this on the floor in the road, but having then road tested the car, the same exact thing is happening - pipe fully disconnected, water sprayed all over the engine bay and steam pouring from under the hood. I shut the car off before I got a low coolant warning this time, but worry I am damaging my engine each time this scenario occurs, and the specialist seem to be out of ideas as to why this is happening.

Has anyone else experienced these symptoms, and if so, what can I do to address it? Having repeated problems with the car is killing all the joy of owning a C63, and making me wish I never spent the £15k+ on charging and preventative engine work that I have done. I only had the work completed in March this year, and for various reasons, it has spent more than half of the time since off the road.

I've attached a picture of the area of the engine where the pipe connects to, you can see the circlip in place - to me, it looked like there is also a potentially threaded hole either side of where the pipe would be when it is fitted - is this supposed to have a bracket of some sort to secure the pipe that I am missing?


Thanks in advance for any help

A depressed C63 fan

NZ-Merc

I would have thought the circlip would have protruded inwards so as to catch the lip on the coolant hose when it is plugged in, how it is in the photo no protrusion to catch on to the coolant pipe and hold it in position?

swedepat

Make sure the spring/clip is seated fully into the hose´s little seat/slot
And make sure the slots aren´t messed up.

offset

Thanks both for the replies, the pipe is new so I don't believe the slots in the the metal collar of the pipe are damaged, and in my pic you can see the circlip is in the recesses of the water pump housing which the hose would locate to - I did just notice though that around the 3 o clock position there looks to be a small notch in the housing, is the end of the circlip supposed to sit in that gap? Does the circlip only fit one way, or is it possible to fit it upside down?

offset

I refit the pipe again today and started the car with expansion tank cap off, I can see no sign of the coolant system being under pressure (bubbles/suction when I cover the expansion tank with my hand), is that a fair indication the head gasket is not compromised? As mentioned its been done within the last 6 months so there should be no issue but there are no guarantees in life....

NZ-Merc

The spring clip has to move in to the slot fully so it protrudes in to the area where the hose plugs in to as so to catch the collar on the pipe.
This may mean removing the clip and giving is a bend/straighten and checking with a mirror once installed.
All the best.

offset

I hope its something as simple as this, the clip looked fine visually but i guess it could not be located properly once fitted. Theres not a lot of room to work in without a ramp and taking more of the front end apart so hard to see if the clip is fully in position. Thanks for the advice

swedepat

When i changed the balanceshaft in my ML350, my lower coolant hose popped off.
I had damaged the small flange at the very end of the hose, this didn´t allow the hose to fully seat in the slots.

30second fix and was fine again.

Phil_T

Which UK specialist fitted the charger and have tried to fix the issues? If you say who this is there is a few people I can recommend to sort the issues.

offset

All the work was done by MSL. I am familiar with other uk independant merc specialists, PCS and the like, but was looking to lean on the collective experience of this forum rather than throw some more money at it

I bought one of head gasket test kits to see if exhaust gases are passing thru the coolant in the expansion tank - the fluid didnt have chance to change colour, as once the coolant was up to temp, the water in the coolant bottle started to flow upwards through the tube and eject the fluid and water! The coolant was not bubbling or getting hot before the point it overflowed - could this be something to do with the thermostat or radiator cap?

Phil_T

MSL are normally pretty good, they have worked on my car for years but I went local this year for its service. Join the C63 AMG UK Facebook page as I pretty sure this is a common age related hose that quite often fails if its the one in front of the engine behind the fan which a special insert fails that keeps it in place. Put a post up on there and you will get help. As you say PCS are great too if your local to them as they are at the bottom of the UK.

offset

Thanks, I think I've started to unpick things a bit more now, having spoken directly with the mechanic rather than Acid, it seems that the hose has NOT been changed, despite them having ordered one for me when I initially described the fault, they jumped straight to head work which hopefully will prove to have been overkill. My hope is that a new hose with a new circlip will see things right. You can the see the current circlip around the water pump housing in my original picture, it looks ok superficially but maybe its just not providing enough tension when the coolant system is pressurised. After trying to do the HG leak test, I put everything back together again and ran the engine up to temp with the expansion tank closed, and rather annoyingly there was no sign of the hose popping off again and coolant temps were fine, however I don't really trust it now, so have got it recovered up to Birmingham today for them to hopefully sort it all out for good.

BLKROKT

So let me get this straight. Coolant hose keeps popping off. Rather than changing the hose, they decked your heads and replaced the block. I would be FURIOUS. Sounds like you need a lawyer. Good luck.

deadlyvt

Yeah that's crazy to read. To replace a block and deck heads for what appears to be a worn clip or hose is pretty ****ty