Who can do a pre purchase inspection in Perth?

[CraigB]

Just saying things as they spring to mind... I don't claim to have the answers. I hope i mentioned this before, but did you test the thermostat in a saucepan? They have been known to stick even when new and should show smooth movement at the appropriate temperature. I'm guessing the 87 is correct and perhaps the 80 was installed with the aim of 'band aiding' the real issue.

To my mind a poorly flowing radiator still would fit the symptoms - sitting idling, lesser air flow and water pump pushing water at a lesser rate and an increased resistance from say less tubes flowing or restricted, and water in the motor rises temp - then forcing more water around with revs and your new fan clutch blowing, and it brings it down more. That also fits if under higher ambient heat it has issues as indicated, meaning that the lesser contact with tubes and tubes to air, that even when flowing best it can, its not meeting that same threshold of transferring as much heat and the block temp going up.

Its an interesting journey anyway and thanks for updating on the continued experiment. Main thing is your not boiling and should all be operating fine without doing any damage in the range you have, like I said originally, I would be more worried about a car running constantly cool and not operating at full efficiency.

[Nabstud]

Keep the thoughts coming, I'm bloody almost out of them haha!!! I didn't test the thermostat in a pot, but both old and new seem to have the same operation. I wonder if the 91 fuel is having an effect on it?

My radiator guy is no longer in business, been a few years since I've used him. Went to another local place and it's $180 to remove the end tanks, rod it and test or appox $500 for a recore (w116 not in their system).

[T-Modell]

Hi,
I'm pretty sure, 91 fuel is not the problem ... imho highly overrated in Oz. As Craig said, first check the sensor / switches. Check resistance while putting it in water and let it heat up. In my harness I took the sensor out of the motor, put it in a water kettle and checked the gauge. As it was boiling it was around the 100° mark, that's fine for me. Imho those gauges are just an estimate anyway.

If the sensors are ok, check if there's air in the system?

Regards
Thomas

[CraigB]

Instinctively, I would go for the rodding first if the core looks externally in good condition. The inside of your motor looks good and I have that thought that 'they don't make them like they used to'. But I assume they are like my local mob who can hook it up and bench test for the percentage of blockage. Also they might not list W116, but once they have it I am sure they can measure and count tubes and have access to a replacement. Also I would hope they could quickly determine if the rodding is going to work or not, so if they change tact to recore, shouldn't cost much more.

[Nabstud]

Went for a good 40km drive on Thursday and a shorter drive today. Temps never went above 3/4 mark BUT on both occasions I put the hvac temperature levers to hot and the temps dropped within 30secs. Looking more and more like the previous radiator “service” wasn’t that effective.

[Nabstud]

Took it to the local radiator guy, explained the issues and what I’ve done. He said it sounds like a flow issue and as an experiment try running without the thermostat to see if it helps. He’s not confident it’s the radiator as it doesn’t fit the symptoms but he said can’t rule it out until it’s checked. A few long drives today and yesterday, including sitting in traffic never got the gauge passed 3/4 or 90 degrees.

[Nabstud]

Could an incorrect thermostat cause the bypass to stay open, therefore reducing the flow to the radiator?

Just a thought, I was looking through the previous owners invoices and it says that short hose under the thermostat had been replaced and made me think the lack of flow could be because the thermostat isn’t closing off the bypass when it opens - how much coolant goes through the thermostat? Both old and new thermostats seem to be the same lengths although I haven't measured. Regardless they both give the same symptoms.

If I remove the thermostat then the bypass will still be open so won't necessarily give a definitive answer. I replaced the thermostat myself when I did the water pump, taking care to position it the same as the old one. The supplier said they only list one type and he seemed pretty knowledgeable on old mercs. Can they be put in upside down - looking at the pics obviously not!

Anyone have a pic or link to the M110 cooling system diagram?

New on left, old on right.



New thermostat installed



Old thermostat



Inside the thermostat housing

[Bartman4800]

Yes, that is the right way up.

When the engine is cold, flow goes through the bypass instead of through the radiator.
When warm, the bypass should be closed but it is never a hermetic seal.
Fluid takes the easiest way around. The bypass diameter is smaller than the other ones.

Bart

[Nabstud]

Cheers Bart, I guess i need to take the thermostat out and measure the depth from bypass hole to thermostat mount and make sure my thermostat is the same when open. Are the bypass valves meant to come in contact with the bypass hole or should it sit proud a few mm?

[tsharkey]

The thermostats do have an orientation arrow like this ^ stamped on it that it should be positioned in the hosing so it points up when installed on the engine.

[CraigB]

I might be misreading or misunderstanding, but the radiator guy says it is a flow problem but not the radiator that is restricting flow? Did he say why "as it doesn’t fit the symptoms" - which symptoms? You put the heater on, increasing the cooling area and temp goes down? I'm not saying it couldn't be something else, just wanting to learn and understand why your symptoms don't fit.

Wish you lived around the corner, I would offer you to pull my rather old and ratty looking radiator and try it in your car. For all the work you've done, this would be an easy way to tell. Took the car for a decent run today, holding back the gears and revving it and trying to put the system under pressure and I couldn't get it to budge past 80. It was a cold day though, but it used to run closer to 90 and i think that was about the rating on the thermostat. I can't remember what i put in there now, but I would prefer it to let it run a bit hotter. And this is with no fan. I have the big W126 560 electric fan mounted up front, but it never turned on.

And your pics all look good - that's how my thermostat is fitted.

[Nabstud]

You make a good point Craig, the only reason I can think that the heaters decrease the idle temp is just another pathway to dissipate some heat, maybe next time I'll leave it idling another 15 mins after turning on the heater to see it the temp goes up again.

He basically said (not his exact words) all the radiators that he finds that are partially blocked all have overheating issues when driving under certain conditions. The fact mine has no issues while driving regardless of ambient temp and load, only to get hot at idle tells him it's a flow issue. To his credit he did say Mercs are not his strong point and that there may be a 'quirk' that he doesn't know about.

I can't say I noticed an arrow on the thermostat, I just put the jiggle hole at the top.

I did take the radiator cap off today after a good run up the highway, when it was idling there wasn't too much coolant flowing by. Revving it up increased it but it wasn't gushing through like I would expect it to. That's why I want to check if the bypass valve is being closed.

[CraigB]

OK, so i think he is saying that if part of the radiator was blocked etc., that you would see an increase in temp still under normal use, but when at idle he thinks it should be still pumping around enough to pretty much replicate the same as when your out driving. Lets say the water pump was pushing half as much because of impeller corrosion etc, then with revs up it keeps up pushing enough around. So that's trying to understand exactly what he is saying. I was thinking then I don't see the difference between radiator reducing flow and water pump, but I guess the radiator is a constant blockage, whereas the flow increases with revs.

Did he know that you did have increased temp under normal driving when the ambient temp was higher - that is right isn't it that when the days cooled down you got more normal operation? And you fitted a new water pump, thermostat and fan coupling? I still feel there is a better fit to describe everything, if the radiator is blocked to a threshold where say half is flowing and the rest not or partial. When you have air flowing through it and nice new water pump pushing the water around quicker, it can keep up, but once you idle and stationary, it reduces volume of water passing through radiator and while the viscous coupling increases its work at idle, and should lock up when hot, its still not passing the same volume of air to cool this reduced flow. Open the heater and you increase the area of radiator, with that same lower flow, and it makes a significant difference. And this is with the bypass working exactly as it is now. No harm checking that though.

I was going to take off the cap and check my own flow, but it was so cool and i forgot to. Can try that again, but will only be a subjective measure. I don't think I would expect a big torrent, but a good visual flow - from memory of other cars.

[Bartman4800]

One thing you could do easily is disconnect both hoses from the radiator, and shove a pressure washer in the top neck.
Catch the water from the bottom flange in a basin.

If any dirt comes out, you know the last radiator service was substandard....

Do the same thing with the heater core, you will be amazed what comes out.

[CraigB]

would you be concerned pressure washer could damage something? Do the tops of the tubes protrude a bit? Because you can't directly blow through the tubes is just getting lots of volume from say a garden hose enough? You can see what comes out the bottom and then another idea, you can put your garden hose in the bottom outlet and seal off with hand or something and back flush to see what come out the top - maybe leave a top hose on so you can direct the outlet into a container. Just thinking out loud.

[Bartman4800]

A radiator should be able to withstand at least 1 Bar.

If a free flowing pressure washer (yes I know they go to 3000 psi/200 bar but you are not pushing into a closed vessel) would damage the radiator then I would be concerned driving it.

A water hose will flush it, but it is the extra speed of the p-washer you need to dislodge the dirt.

Bart

[Nabstud]

Yes, same issues happen in hot or cold weather, just in cold weather it takes much longer to get hot when idling. Told him that too, maybe it was information overload for him!

This morning I dropped the coolant, removed the thermostat and did some measurements. I also put the new and old thermostat in a pan on the stove to check operation (don't tell the missus haha!)

Thermostat housing depth to bypass hole - 38mm
Thermostat bypass hole diameter ~ 39mm

Old thermostat - 82°C
opening temp - 80°C, fully open about 86-89°C
opening depth at 95°C - 38mm
width of bypass blocking plate - 36mm

New thermostat - 87°C
opening temp - 85°C, fully open about 89-91°C
opening depth at 95°C - 35mm
width of bypass blocking plate - 43mm

The old thermostat opens so the blocking plate is flush with the bypass hole but there is ~2mm gap around the edge.
The new thermostat blocking plate sits 3mm above the bypass hole but has 7mm bigger diameter than the old one.
I imagine that these gaps are negligible when compared to the open portion of the thermostat?

I ran the car without thermostat for a minute and the flow didn't change much from when the car is hot and thermostat open BUT I couldn't block the bypass hole to force the water through the radiator.

I had another good look into the radiator and I could see a bit of crud in a few of the tubes so I bit the bullet. I wasn't confident to stick my pressure washer in the radiator so I took the radiator out and dropped it off at the radiator shop to get tested and rodded properly.

Back to the subject of coolant, anyone recommend a supplier and appropriate coolant brand in Perth?

Difference in width of bypass blocking plates

[Bartman4800]

https://www.penriteoil.com.au/products/ ... oncentrate

I would go with Penrite, this is what the selector recommends. Has the MB 325.0 type approval.
Available at Repco, Supercheap etc..

Otherwise buy the MB stuff from the Forum Sponsor

[Nabstud]

Cheers. Just curious, any reason to go that over the Zerex G-05? Both say MB Approved but neither are on the MB list, then again I can't find anything other than genuine MB fluid in Australia from that list that AMG updated.

Looks like the forum sponsor no longer does spare parts? Unless I'm looking in the wrong spot.

[Christo C]

Those Thermostats are quite different IMHO; how do you know which one is correct?
It is really important to have the exact Thermostat.
I would be going here:
https://partsouq.com/en/catalog/genuine ... cedes-Benz
and entering my VIN, then looking at the "Engine Cooling System" drawings and find the correct Part Number for the Thermostat.

[Nabstud]

The smaller one is a BEHR one and the bigger one is just a JD one, got it from an online euro parts shop.

My vin is only 14diguts and doesn’t work on that site

[CraigB]

Based on the tests, I think both thermostats are working well enough that it isn't your problem, the BEHR would be OE and looks like the one i fitted to my M110 and is working perfectly. I think if you put 'WDB' in front of the numbers, that should give you the 17.

I'm confident the Penrite is fine, but make sure its their green and not the blue. In other threads you will see I am frustrated they chose a different colour to what was the traditional colour of the OE fluid, but then i guess they wanted to differentiate it from the later blue formula. There was an example where this person had their head reconditioned and ran the later formula and had to remove it again after a relatively short period (year or two?) and had some pretty serious corrosion. Its not a scientific experiment proving that is the reason, but sure as hell made me think I am only going to use coolant of the spec that the manufacturer specifies. Why wouldn't you?

I don't see any difference to using the Zerex either - i've never used it but if it meets the spec, I would be confident to use it. I see big W has the Zerex all mixed for $25/ 5l - need 10l, so similar to Penrite. Its green i see.

[Nabstud]

I think the issue is resolved. Got the radiator back on Wednesday, the guy said it was maybe 30-40% blocked, a bit of muddy crud came out of it. Looks like the previous "service" may have just been a chemical flush or similar, it has definitely been out of the car and at least painted haha!

I flushed the cooling system with a flushing additive, I didn't want the crap going through the newly cleaned radiator so I bodged up a temporary radiator out of a bucket to try and catch any crud floating around. I first tried it with my modified thermostat - guts ripped out of it- but there was bugger all coolant coming out of the radiator hose into the bucket, it was just circulating around the motor. So I put the good thermostat back in, lasted 15mins until the temp gauge got to 3/4 mark and I pulled the pin.





I let it cool down, then rinsed it out, refilled with water, went for a drive to warm it up, drain, flush, repeat... Did it 3 times over the last couple days. I put a radiator sock in there to catch any crap and stop it blocking the radiator again. Not much crap came out of it, although I did flush it out with a hose a few weeks ago when I did the water pump.

Radiator sock new



Radiator sock after 2nd flush, caught a few small bits of crud.



All the crud after 3 flushes.



Took it for a 10min high speed run this arvo, the temp gauge just sat under half the whole time. I got home and left it to idle for 30mins, gauge just stayed about half way. After 30mins idling the thermo gun said 83°C top of radiator and 69°C bottom of radiator.

Only got a smidge higher than this after the 30mins idling.



I won't be 100% satisfied until it get tested in summer but I'm pretty happy with the results. A few of you said the radiator was the cause but I wasn't convinced due to the "radiator serviced - $236" on an invoice from just over 12 months ago. It either wasn't done properly or has filled up with crap in 12 months - considering the little amount of crap that came out I suggest the former.

Still has water in it, I'll drain and flush it one more time then fill it up with Penrite coolant over the weekend and enjoy my cool idling car!

[CraigB]

Good news. I hadn't seen one of those radiator socks before - great idea. I wasn't sure from your post, but the bucket worked did it with the normal thermostat? I like that idea too.

Like you say, will be nice to test it in a summer, but I'm glad it was blocked and quite possibly the case. I kept coming back to that as fitting, but I wasn't confident and its been good to go through all those things. Mind you in the meantime, another person I know had similar issues and it was his thermo coupling, even though he didn't have a problem before getting a hole in a core plug and leaking fluid and overheating it. He pressure tested the system and didn't have behaviour of a head gasket failure and my thinking was the overheating dislodging stuff that blocked the radiator. You would think the thermo coupling would be something to be black and white affected by the overheating. And then my problem a week ago that I thought was waterpump and was just a thermostat that again 'black and white' - working perfectly one minute and disaster the next. All lessons!

[Nabstud]

The bucket did work great, but next time I would use a much bigger bucket! Without a radiator to cool it down or a fan to give airflow the coolant quickly got hot. Was good to see when the thermostat opening and the water started swirling in the bucket, a good visual aid to help understand his a thermostat works!!

It’s funny how symptoms can be misleading, and a good example of different part failures can have similar symptoms. I only noticed yesterday that all the coolant hoses have now been replaced except the heater hoses. Wish I noticed them earlier, I would have changed them too... will see if I can get some soon then the whole cooling system has effectively been replaced!!!

[Nabstud]

Done almost 250km since doing the cooling system. After today's highway drive it sat idling in the driveway for 25mins, max temp at top of radiator was 89° and bottom 79°. Slowly got there after about 20mins then just sat there. Turning on the AC/electric fan saw the bottom radiator temps drop to 76° in about 10secs, then after a little while the top radiator temp started to drop so the extra airflow is helping. The idle had been a bit low and sounded like it was missing so I played with the 2 idle mixture screws. Screwed one in until the idle started to sound worse then backed it off until it came good, then did the same with the other one, only about 1/4 turn max each time. Went back and forth a few times until I got it idling pretty smooth. This seemed to also get the temp down a couple degrees, probably due to a bit more coolant flow due to the slightly higher idle.

I took out the filter sock, no matter how tight I did the top hose clamp it kept on weeping coolant. Barely caught any muck so I was happy that I flushed the cooling system enough.

[CraigB]

That sounds good to me, I wouldn't want it to run any cooler than that for best combustion etc.

[T-Modell]

Hi,
I'm still waiting for the photo without hood, your wife sitting on the fender, measuring the temperature with an infrared thermometre while you're driving ...

Thomas

[Nabstud]

I’ve asked, believe me I’ve asked!!!!