New member -Is it a lemon?

[dennisr]

Hi all, back in early August I parted with $3.5k and drove a 1988 300CE 3.0L W124.050 home from Perth to Manjimup(300+km) Then we noticed it blowing white smoke....hmmm? Then we noted small black oil deposits in coolant tank...but oil looked good. WE noted that there is always heat coming out the demister vent under windscreen and the two side vents on each side of car. The buttons in the middle of the climaTE console do not respond or do anything. But then we found that if you wiggle the ignition key towards the off position a smidgen, the fans all come on in the car and the top auxillary fan button will light up and fan at front of radiator will come on...even if car is still cold.?!
So we thought that the coolant may need flushing and did that. But afterwards the car began to overheat seriously!
We drove it 30km to the next town and temp guage fine, goes well up hills, then when we slowed down to 60km at the town, the temp goes into red. speed up and it goes down. But we stopped car to get drinks from shop. Came out after 5 minutes and there was a river of new coolant leaking from car. It was bubbling in overflow tank and the tank was full now car stopped. The coolant was being forced out through the overflow hose to the roadway.
Had to wait ages to put more coolant in and started car and drove home --temp good on highway, but when we got to 60km zone up it went again, front fan was on.
Parked car in carport and lost all coolant again through tank. This was back in August.
September 2018 --took the plunge and removed cylinder head. The gasket was an absolute mess. There were build ups of some kind of gasket stuff --guys at work said it is chemiweld when they saw it. Took head to justheadworx in Bunbury and paid $900 to have heaps of welding done, pressure test, honing and new valve guides from Pelican parts put in. MB in Bunbury wanted $99 +GST for 1 valve guide!! I got 12 inc postage for $224AUD and that because I paid $81 USD for express Fedex freight.
While head was off, I took heater valve apart. It is a Sitronic duo valve even though I think this model w124.050, m103.983 is meant to be a single valve? Anyway the rubber seals inside are torn and perished. The cylinders scored, just a mess. I put it back together and didnt do anything about it.
When we got the head back to put on block the mechanic had put cam in wrong TDC position not based upon the right timing mark on the flange on the cam.--the 21&22 marks.
So that meant we had to loosen off the rocker bearing assay bolts to move cam shaft about 90degrees to be at TDC....gotta realise that I had no experience prior to this....just following threads and manual etc. scarey, anxious, effected my sleep and mental health!!Dinkum! My take home pay is only 630 a week...and this car is a nightmare so far of which I was not aware.
Anyway---when we went to tighten the rocker bearing cap bolts down to 15nM 6 of them stripped the aluminium out of their holes in the head. So I had to helicoil them which I had never done either....and in the end we helicoiled 10 bolt holes.
So head back on, then new Idle control valve fitted and new breather pipe to the cold start injector....new voltage regulator...new EHA fuel regulator as it was leaking fuel onto intake manifold! New coolant again....new rotor and plugs and leads....fired it up and it purs fine....
Then the exact same ting happened yesterday Oct 3....drive around town in 50/60km zones and get home and it pshes all coolant out coolant tank overflow hose. aaaaaagggghhhhhhh!!!!!!
It cant be the head causing exhaust gases to get into cooling systemmmand besides it happens when car slows AND STOPS.
Do you think it is the coolant pump, heater control valve, heater core or what???
Going mad here! No doubt the previous owner was on this same forum with this bucket of bolts until he gave up and sold this lemon to us.
Dennis

[Bartman4800]

Overheating is most likely a blocked radiator.

Bring it to a rad specialist to have it checked. Likely the chemiweld has not done any favours to the radiator.
They might be able to clean it, otherwise you are looking at a replacement radiator.

Also, it is possible that you have trapped air in the system. See if it is fully bled...

Are you aware there is a drain bolt at the bottom of the engine near the engine mount?

I feel for you...


Bart

[dennisr]

Thanks Bart for the reply! The radiator looks new, but yes, that is my next step. my son was the one who topped it up with coolant, when we get back from a few days in Denmark WA shall see if it has an air lock. Yes I found the 19mm drain valve on drivers side of block.
What about the heater core, would that be blocked too from the chemiweld?
And the heater valve solenoid thing, it is cactus.... I read on another thread that a failed heater control valve killed the climate control unit on another Perth member's car ...viewtopic.php?t=22114

[Bartman4800]

Yes, the heater core could have blocked. But even if it is it should not really affect the cooling capacity. It could however retain a big air bubble if it is.

Do yourself a favour and replace the thermostat as well. And make sure it is mounted with the air valve upwards. The air valve is a little thingy that looks almost like a little knob that little girls wear when they receive their first punctures.
It lets a little bit of flow through and makes sure the air is vented out.
Are there any hoses plugged off to the heater or such?
Do you see any bubbles in the radiator or expansion vessel when the engine is running? That would still suggest a gasket leak...


Bart

[Christo C]

I think overheating caused the original head gasket problem, and it is still a problem; a common one in W124s.
Apart from the advice to check radiator, coolant pump & thermostat, you need to be sure the the temperature guage and, most importantly, the temperature “thermo “ switches in the head which control the fans are working correctly.
As a guide, your temp guage should NEVER read over around 100 degrees when crawling in heavy traffic, and should sit mostly around 80 degrees in most other circumstances.

[dennisr]

Yes, the heater core could have blocked. But even if it is it should not really affect the cooling capacity. It could however retain a big air bubble if it is.

Do yourself a favour and replace the thermostat as well. And make sure it is mounted with the air valve upwards. The air valve is a little thingy that looks almost like a little knob that little girls wear when they receive their first punctures.
It lets a little bit of flow through and makes sure the air is vented out.
Are there any hoses plugged off to the heater or such?
Do you see any bubbles in the radiator or expansion vessel when the engine is running? That would still suggest a gasket leak...


Bart

The T Stat is new., no hoses are plugged, but as I said in the original post, the duo heater solenoid valve is cactus. no bubbles in tank.
Radiator blocked up, ordered new Nissen one from Melbourne...$302 + $100postage to regional WA!!

[dennisr]

I think overheating caused the original head gasket problem, and it is still a problem; a common one in W124s.
Apart from the advice to check radiator, coolant pump & thermostat, you need to be sure the the temperature guage and, most importantly, the temperature “thermo “ switches in the head which control the fans are working correctly.
As a guide, your temp gauge should NEVER read over around 100 degrees when crawling in heavy traffic, and should sit mostly around 80 degrees in most other circumstances.

In fact the head was very badly corroded, the gasket was a mess and there was chemiweld put in to stop the leaks.

[dennisr]

the head gasket was badly blown and the water ports in the head were clogged up. The guy at justheadworx in Bunbury had to chisel out the solid crap in the ports! :whistle:

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[Christo C]

....the duo heater solenoid valve is cactus...

Yes, when those fail, they fail "ON", therefore coolant is always flowing through your cabin heaters, which is more of a problem in Summer; however this failure does NOT cause the engine to overheat!

No doubt failing ON was considered the best option by engineers used to living in very cold climates

[Whilst searching for a replacement Duo Valve you could disable the Circulation Pump (just unplug the connector on the small pump in the small hose between the Water Pump and the Duo Valve) and block (squash) the hose somehow - at least then your heating won't be on all the time.]

I just hope you have not blown the head gasket again, or warped the head.... I know the M102 engines are very touchy in regard to overheating, but don't know much about the M103 engine.

[Ivanerrol]

When you get the radiator checked, have the specialist do a pressure test.
Water pumps in those eighties sixes have a habit of failing.
You symptoms of slow speed overheat and high speed O.K. sort of indicate to me that the radiator is working.
You need another duo valve - there are no good second hand units around.
If you need a water pump only get a Graf or Laso - any Chinese knockoffs are worse than useless.

[dennisr]

update and clarification...
I am waiting for a new radiator as the rad place said that they can never get the aluminium and plastic ones to reseal properly. I told him that chemiweld had been run through cooling system by previous owner and he said you would need a new radiator based on that alone. So we wait for the new Nissen from Melbourne.

But just to clarify.
The overheating happened before I got the head done.
When we put the head back on and topped it up with coolant for its first start since having the head done it idled well, the thermostat opened and temperature stayed good at around 90 idling.
My son drove it for 5 minutes or so around town at 60ish km/hr...the temperature was fine, did not move up.
He got home and parked it in front of house.....went inside for a few minutes...came back out and moved car into carport at side of house.

Now previous to having the head done, we did have serious overheating and you could hear the coolant boiling in the heater core! That was before!
My son said the gauge was fine this time, and he could not hear any gurgling or bubbling noises as he parked it up for the night.
Next morning when he went out to it, there was coolant everywhere!! But mainly from below the right hand wheel arch where the overflow bottle is.
That is why I suspected that the expansion tank must have been filling up and overflowing to the overflow bottle hidden in the wheel arch and dumping onto the ground.
Trouble is he never actually sighted the expansion tank doing that. It was just my theory as I was away at the time on holidays.

So if it did not overheat then it may have simply been a leak and I have wasted $412 on a new radiator!
But it did not start leaking until it was parked overnight and cooling down from being driven up to operating temperature. The entire expansion tank was emptied out after that "leak".
So not having been there to see everything, just a 17 year old totally inexperienced boy saying it did not overheat...and then next day he saw coolant everywhere and an empty expansion tank...???

Also if anyone knows what the radiator thermo fan temp switch looks like and where it is I would be thankful! It is an M103.983 motor.

[Bartman4800]

The fact that you heard bubbling in the heater core tells me there is a lot of air in the system.
You have to get rid of that first before you can assess the cooling system properly.

The heater valve is stuck open, so that will not prevent air from bleeding.
I am not versed on bleeding air out of a W124, others here need to advise on that.


Bart

[dennisr]

yeah thanks, but we heard the bubbling BEFORE we had the head removed and drained all coolant to replace it. We did not hear any bubbling this time since head refitted and new coolant....well my son didnt hear it anyway.
There is a bleed screw on the Thermostat housing....and a plug on the cylinder head. When I put the new radiator in, I will do my darndest to bleed all air out. Are you saying I wont be able to bleed it out if the heater valve is not working?

[dennisr]

oh, sorry you said it will not prevent bleeding.

[dennisr]

and I found a thread on here about radiator temperature sensors

viewtopic.php?t=20789



AMG posted a picture of 4 coolant temp sensors for the M103 motor--same as mine. Each one of them is a 3 pin type. I don't have one like that on the cylinder head...would it be mounted somewhere else?

[Christo C]

Part # • 006 545 45 24 (used in some M103s) 105ºC/115ºC with green top; ONLY USED WITH AIR CONDITIONER 105/115 GRAD

That sensor, if fitted, is towards the back of the Cylinder Head.

....Have a look at https://partsouq.com/en/catalog/genuine ... 502A674200
if you hover mouse pointer over Part 90 in the diagram you will see the location and the part numbers for that part will highlight in the parts list.

To diagnose cooling problems properly, like most other systems, you need to observe them in operation, and not make assumptions based on hearsay and guesswork by others who can't observe for themselves ....

In general you can see a listings for most parts for your VIN at https://partsouq.com/en/search/all?q=WDB1240502A674200

[dennisr]

Thanks for all that christo!

[CraigB]

To diagnose cooling problems properly, like most other systems, you need to observe them in operation, and not make assumptions based on hearsay and guesswork by others who can't observe for themselves ....

I totally agree and on forums we are all trying to help and chucking our experience and thoughts your way but you need to be careful to see if that is relevant to your specific situation.

The only comment i wanted to add is that I think that tank in the guard doesn't empty itself and if earlier overheating filled it up, unless you specifically emptied it I think it may still have been holding fluid. So seeing fluid may be just what has bled out on top of what was already in there. I'm not sure about that but I think you just need to concentrate on if it is keeping between the marks on the header tank and not losing it from there.

Has radiator cap been mentioned? If its not maintaining the correct pressure that will cause overheating and loss of fluid and one of those things often forgotten.

I don't know your engine but generally filling it while something is undone at the highest point of the motor is open. Then start it up and run it with radiator cap off and system under pressure until thermostat is open, will normally do it, but some cars are known to be pains for airlocks - but no idea if yours is one of them.

[dennisr]

thanks Craig....yeah the overflow bottle thing under wheel guard was empty, but I think the hose had perished so that the coolant simply bypassed the bottle to the ground. It had a tiny bit in it when I had taken it off and tipped it upside down. At this stage I don't think it did overheat. Everyone keeps saying overheating, but I never said it is doing that now. That is what it did before I had the head done.

Anyway as you all say forums can just cause you to chase ghosts even more than I do on my own. hahaha never mind. Thanks for all your time and help guys.

[dennisr]

Part # • 006 545 45 24 (used in some M103s) 105ºC/115ºC with green top; ONLY USED WITH AIR CONDITIONER 105/115 GRAD

That sensor, if fitted, is towards the back of the Cylinder Head.

....Have a look at https://partsouq.com/en/catalog/genuine ... 502A674200
if you hover mouse pointer over Part 90 in the diagram you will see the location and the part numbers for that part will highlight in the parts list.

To diagnose cooling problems properly, like most other systems, you need to observe them in operation, and not make assumptions based on hearsay and guesswork by others who can't observe for themselves ....

In general you can see a listings for most parts for your VIN at https://partsouq.com/en/search/all?q=WDB1240502A674200

Thanks for the links to the exploded view of the head for my m103.983.
The list of sensors on the head is interesting. The one marked 90 has 3 variants. The one I have in the head at present from when I bought the car is the first part number mentioned for "90" ...it is the blue two pin variety. It is just called Temperature Sensor.
https://www.autodoc.co.uk/spares-search ... +542+45+17
But then the second and third options are called "Switch, automatic" The second one marked as "90" on the diagram is a green top 3 pin type.
https://www.autodoc.co.uk/spares-search ... +545+45+24

I am wondering if the 2 pin is the wrong one for an automatic 300CE with an M103.983 in it?? Who would know that kind of stuff?

[dennisr]

Screenshot from 2018-10-09 07-47-07.png

[Christo C]

I only saw 2 options for Part 90 - one with 2 pins is Sensor (variable resistance according to Temp) and the other with 3 ins is a Temp Switch; unlikely to be interchangeable - the clue is how many wires run there and the mating connector.

Thing is, there are quite a few variations in how your cooling system is set up and it would pay to have someone familiar with it look at the whole system.

In a nutshell, the cooling system is Pressurized and the Expansion Tank on the wheel arch is very much part of that - when the engine warms up, a pressurized system prevents the coolant from boiling (liquids under pressure have a higher boiling point) - the air in the Expansion Tank is also under pressure, and it is normally the only air in the system.
When you stop the engine the cooling system should remain at pressure until it cools down, so if there is a coolant leak anywhere, except in the Radiator Cap, that air in the Expansion Tank will expand and push the coolant out of the bottle. Thus the bottle will appear to empty first.
As the engine warms up the Thermostat should allow coolant to flow through the Radiator. The Water Pump just keeps the coolant circulating, and has nothing to do with 'pressurizing' the system; that is achieved purely by heat.
If the coolant gets too hot normally two things can happen - the fan at the front of the Engine will come on and drag a bit more air through the radiator; if that is insufficient, then the electric fan in front of the radiator should kick in. (I am not entirely sure how those fans are controlled in your vehicle; in my M102 the 3-pin Temp Switch looks after that...)
If the coolant gets way too hot the pressure in the system will become too high, and will release pressure via the Radiator Cap (on the Expansion Tank) - that is there just to protect the system and prevent hoses bursting etc, and doesn't prevent the temperature rising.... some variants blow the excess out into the world, some blow it into an Overflow Tank. .... see https://partsouq.com/en/catalog/genuine ... 502A674200

Thus all the components in the Cooling system have to be in good working order.

Having said all that, it should be easy enough to run the engine until it warms up and observe for any leaks. Craig mentioned the Radiator Cap - that is a quite common cause of lack of pressure.

Be careful with a hot cooling system - the coolant is hot and under pressure!

[dennisr]

Well, the mercedes 300ce is running again. New radiator fitted today and new coolant and new thermostat and 2 new sensors. Temperature rock solid. My son drove it 120km to Bunbury this evening without a problem.
I was nervously waiting the dreaded text message, but it never came. :whistle:
Still idles a bit high though....anyway for now we are stoked that it is actually back on the road after over 2 months in the shed! :dance:

[CraigB]

Good news! thanks for letting us know.

[Christo C]

Yes well done. Remember to always drive with one eye on the Temperature Gauge!

[dennisr]

I should tell you guys what happened with bleeding the air from the system yesterday. We topped up the radiator slowly and heard it filling up and then you could hear it further into the engine blup blup blup as it filled the water pump area I think...I had the thermostat breather screw out and the coolant came right up to it(this is with a stone cold engine) so I put it back in. Then I undid a spare sensor plug on the right side of the head where the other sensors are. I imagined that the coolant level inside the water jackets would be down ...but as soon as I pulled that plug coolant came out everywhere.....had to plug it with my finger and reposition the copper washer and put that plug back in quick!
Then after checking and doubling checking for any leaks my son jumped in started it it up. The expansion tank cap was off and I was watching the level and adding coolant accordingly --it didnt need much more...BUT THEN!!
When the temperature got to 87 and the thermostat opened a great big surge of coolant came pushing up out of the expansion tank!! It was bubbling and steaming angrily...I was like...OH NO!! THE HEAD GASKET IS GONE!!??? But it only lasted a few seconds and settled down....I added more coolant and the level sat quietly in the expansion tank. The temperature sat at about 85. So it was an almighty bubble of air that expelled coolant. After that we drove it in short 400m trips down our street and back and stopped to check for leaks until I was satisfied...paranoia!