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W03 2.1, 2005 - Engine Block Coolant Plug

H

HITECH

Active Member
Joined
Dec 25, 2014
Messages
647
Location
coldest place in scotland
Car
C220 CDI
Hi Ive had a catasrophic fault with coolant loss. Thankfully the car told me there was a problem with loss of coolant in expansion tank. So I took all the under covers off the car and traced the leak to some kind of gold coloured looking engine plug. Is this called a freeze plug or something ? The car has done a lot of miles ( almost 200,000 ) and has been meticulously serviced by myself regularly every year so the engine and running of it is well looked after.
I have a few questions. I looked in my haynes manual and there is nothing about this plug in the manual at all so im left to try find out what the part is and get it ordered. Its right on the right side of the block ( as ur sitting in drivers seat looking forward ) just above the DPF. Really really awkward to get at aswell. It looks like its a bolt in the middle of the recessed plug.

1. What is it ?
2. Where can i purchase it from ?
3. Is there any things to be careful of when replacing it ?
4. Any idea what size the nut is fo rmy car ?

Hope somebody can help. This is a pain. Car not moving and got ppppppppplaces to go, people to see....the usual :(
 
Ide really appreciate it if some kind Mercedes gentleman could possibly find the part number for me if I give you my VIN. Fingers crossed here. ......
 
HITECH said:
That part number was bang on m8. Thanks. I had already ordered it by vin but part number you gave also matched. Very much appreciated info. Thanks for taking the time to look and check.
Click to expand...

Posting up your reg number is enough for most of us to check with EPC (for correct part number) if you don't want to post your VIN. ;)
 
Assuming you have blown a core plug out? You really want to understand why that happened. It may just blow it straight back out. These are designed to release pressure in the block to stop it cracking. Usual cause (they very rarely fail). Is pressure build up caused by prolonged overheating? Or by freezing with no anti-freeze.


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The purpose of them has absolutely nothing to do with being a valve to release pressure. They were put in during the molding of the engines to withdraw any excess sand/washing down after the molding. I have looked into it and used my own qualifications in metallurgy & inspection to understand the point of them. They were given the name freeze plugs by usa / uk ? I have no idea. But yes you are right one technical term for them could be a core plug. In the 3/4 years Ive owned the car. It is meticuously serviced by myself and the water and oil are both checked at least weekly. The reason why the core plug has gone is the car has done almost 200,000 miles and the plug is corroded. Might have taken a battering in previous owners care ? No idea bud but a possibility eh. There is nothing complicated about it or any need to understand anything. The anti freeze is always bang on. The water pump is fine and the thermostat is working and opening as normal at the correct temps. The basics are covered. They very rarely fail ? Its more like they are very rarely spotted that they have failed unless you put die in ur water and actually trace it back to the pinhole corroded bit in the plug that has leaked. Most people Im guessing assume the head gasget has gone because the water drips down the side of the block and I understand why some people could come round to the assumption that the head gasket has blown WHEN IT HASNT. So no Bruce I dont want to waste any of my time thinking about the logisitics of it. Simple fact being. It corroded and leaked. I will get pictures of this job up on here when im replacing it. Hopefully it will help others with the same problem. Theres ALWAYS a slim chance that any new part you fit onto an engine will possibly happen again no matter what the part is. But thats just a negative way of thinking lol Any complications and I WILL update for defo. Gimme some happy banter now on this Bruce coz the sun is out this week m8 ;)

brucemillar said:
Assuming you have blown a core plug out? You really want to understand why that happened. It may just blow it straight back out. These are designed to release pressure in the block to stop it cracking. Usual cause (they very rarely fail). Is pressure build up caused by prolonged overheating? Or by freezing with no anti-freeze.


Sent from my iPhone using Tapatalk
Click to expand...
 
HITECH said:
The purpose of them has absolutely nothing to do with being a valve to release pressure. They were put in during the molding of the engines to withdraw any excess sand/washing down after the molding. I have looked into it and used my own qualifications in metallurgy & inspection to understand the point of them. They were given the name freeze plugs by usa / uk ? I have no idea. But yes you are right one technical term for them could be a core plug. In the 3/4 years Ive owned the car. It is meticuously serviced by myself and the water and oil are both checked at least weekly. The reason why the core plug has gone is the car has done almost 200,000 miles and the plug is corroded. Might have taken a battering in previous owners care ? No idea bud but a possibility eh. There is nothing complicated about it or any need to understand anything. The anti freeze is always bang on. The water pump is fine and the thermostat is working and opening as normal at the correct temps. The basics are covered. They very rarely fail ? Its more like they are very rarely spotted that they have failed unless you put die in ur water and actually trace it back to the pinhole corroded bit in the plug that has leaked. Most people Im guessing assume the head gasget has gone because the water drips down the side of the block and I understand why some people could come round to the assumption that the head gasket has blown WHEN IT HASNT. So no Bruce I dont want to waste any of my time thinking about the logisitics of it. Simple fact being. It corroded and leaked. I will get pictures of this job up on here when im replacing it. Hopefully it will help others with the same problem. Theres ALWAYS a slim chance that any new part you fit onto an engine will possibly happen again no matter what the part is. But thats just a negative way of thinking lol Any complications and I WILL update for defo. Gimme some happy banter now on this Bruce coz the sun is out this week m8 ;)
Click to expand...


You I read the same Wikipedia page as I, before I posted. But then I fell back on my scant knowledge gained in 40 + years of performance engines and their dislike of temperature +/- ;^)

First rule of trouble shooting: Everything happens for a reason. Find the reason you find the answer. If your plug is rusted, your coolant passages may also be corroded/blocked/sludged up. You will now that this very common on "higher mileage" engines where correct maintenance may not have been applied. A common issue being the use of different chemical compounds in anti-freeze, this can lead to the antifreeze crystalising in the passages or forming a jelly. Easily checked by gaining access to the passages, some say you can use a bore scope or fiber camera?

Last week we looked at a rather beautiful Lancia Delta Integrale - fully factory built & Rallye prepared. It only ever runs in competition. It blew a plug. This was evident when the co-driver spotted, rapid;y rising engine temps. As they slowed it blew - luckily not seizing the engine. The coolant passages were furry from use of the wrong anti-freeze or possibly none at all.

To replace the plug (10 pence) the engine had to come out to gain access. The opportunity was taken to strip the engine and do some overdue deep maintenance.
Good luck.
 
Im not expecting any sludge because I have changed out the antifreeze regularly. But there might be. I will be flushing it thru anyway. I wont be just replacing the plug without doing a little preventative maintenance. Thank you for your input. The engine will most certainly not be getting removed as its not a race car and has never overheated. Is just my trusty every day user saloon. As far as trouble shooting goes Im an electronics surface mount de-bug technician (to trade) with a degree in metallurgy&inspection. I know the principles of fault finding a fault. I appreciate your 40 years of experience and input. Thank you. Now you can give some positive input ? As far as wikipedia goes I dunno what you mean. I found my info from a mechanic and then applied my own qualifications to the understanding of castings and engines which was a large part of a 3 hour graded exam I had to sit to pass. The basics of them plugs and their reason for failure are nothing complicated. Im just joe bloggs on the street . I do not have cameras and stethoscopes. Where would be the sense in puting car into a garage to get the engine removed and a camera and stethoscope testing things on it? It would way over exceed the worth of the car. Labour for removing and puting an engine back ??? Close to £1000 nowadays then their is addional costs for any actual work done. We are not long out of a double dunt recession and money is tight in this country lol The chances of the same anti freeze being used in a cars lifespan are slim to none as we are all different human beings. In an ideal world that would happen but we are very different in our own unique ways. The compounds in anti freeze u mention all have exactly the same 2 principles. every single one of them. to stop the coolant freezing and protect from rust. I will keep this thread updated and thank you for your input. Positive and negative input is always good. Now gimme your positive inputs Bruce. Cmon :)

brucemillar said:
You I read the same Wikipedia page as I, before I posted. But then I fell back on my scant knowledge gained in 40 + years of performance engines and their dislike of temperature +/- ;^)

First rule of trouble shooting: Everything happens for a reason. Find the reason you find the answer. If your plug is rusted, your coolant passages may also be corroded/blocked/sludged up. You will now that this very common on "higher mileage" engines where correct maintenance may not have been applied. A common issue being the use of different chemical compounds in anti-freeze, this can lead to the antifreeze crystalising in the passages or forming a jelly. Easily checked by gaining access to the passages, some say you can use a bore scope or fiber camera?

Last week we looked at a rather beautiful Lancia Delta Integrale - fully factory built & Rallye prepared. It only ever runs in competition. It blew a plug. This was evident when the co-driver spotted, rapid;y rising engine temps. As they slowed it blew - luckily not seizing the engine. The coolant passages were furry from use of the wrong anti-freeze or possibly none at all.

To replace the plug (10 pence) the engine had to come out to gain access. The opportunity was taken to strip the engine and do some overdue deep maintenance.
Good luck.
Click to expand...
 
The common issues with anti-freeze are it's unknown history in relation to certain cars (possibly yours included) and the changes/improvements in chemical makeup over the lifetime of an engine. OAT is the most commonly used and available, but does not work well with systems that have brass or copper fittings, it also does not mix well with IAT. What tends to happen is people buy "anti-freeze" and top up the system with anti-freeze, with no knowledge of the potential for failure that they may have just added to their car. That becomes apparent later when engines blow water pumps, thermostats, radiator caps etc. These tend to blow due to the build up of crystals or sludge caused by mixing the OAT and IAT or indeed, by just using tap water, which corrodes the internals of the waterways. It can be quiet a shock to some when they are confronted with this "blocking" . Cleaning it can be done with flushing agents and removing the engine block drain plug. Often when the engine block drain is removed nothing comes out? Well maybe a drip :^) this is sure sign that the waterways are blocked and trouble is waiting to happen.

One thing to watch out for is the colour of the anti-freeze - Blue, Pink, Green etc. This usually has no bearing on anything apart from the colour and is not an indicator of the chemical makeup. Many have argued that it should be an indicator. So replacing Pink with Pink is not always the same as replacing OAT with OAT.

My last point. I write this to help both you and others who come here looking for help. It is not a 'willy' waving exercise. Having experienced some of the most spectacular and complex engine failures (some on here) I just want to help. It's free help and given willingly. My "troubleshooting experience" relates directly to my job and Kepner Tregoe, who in sometimes stating the obvious, remind us all of the need to state the obvious. "Things change because something or somebody changed them" is a classic, that benefits us all. How many times do we hear the chant "It was working fine this morning?"
 
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Mine leaked on my W210. It was awkward to do without removing other stuff so after a lot of (my) labour I did it. Tapped back in with a large socket and it has been fine since. I put it down to age and corrosion, possibly caused by topping up with water and not coolant over a period of time
 
It would appear from this diagram there's a seal ring associated with it?
CYLINDER CRANKCASE MERCEDES OM646 (646963)

getImage.php
 
Thank you guys for the input. Yeh Bruce 1 priority when flushing it will be to make sure it is completely clear. The plug will not be going on until thats done. Grober thank you very much for that diagram. Thats excellent for reference. Going by that diagram does that mean there are actually 2 plugs on that engine ????? 1 on each side of the block ? What is no53 and 95 beside it ? Ive included some pictures here for reference. This is the replacement plug. The part number (as kindly given by pmcgsmurf) is A1179970230 and the equivient part number is 38554.
Pic1.jpg pic2.jpg pic3.jpg
 
So this Mercedes block has two holes either side of the block,and given the plug has a thread and a rubber seal,the block has been faced and tapped to accept the plug,it would seem that this mercedes block has two good old fashioned drain plugs for the coolant in the block,great news that it was not a core plug like I and Bruce thought,they are a pitta to get out and replace with the engine in the car and the op has the plug and it seems he can get to it so jobs a goodun.
 
As said, I would say 47 is the freeze plug and this is a drain plug
 
The drain plugs are "normally" threaded and fairly fragile. If removing it to drain the block use a good quality key and a soft rubber mallet to tap the key home before attempting to turn it. They can tear and then you have a horrible job to get it out. Best keys are the ones with a socket drive/head. Halfords Advanced just a a great offer on their tray sets for these socket keys. Not sure if that is still running?
 
PICTURE OF THE COOLANT DRAIN PLUG
10438305_1024x768.jpg
 
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