M119 Running hot

[EHKO]

Hello all! First post here, though I have been stalking and using info from 500eboard for many years now, as it is one of the few websites that provides good detailed info on the M119 motor.

I decided nearly 8 years ago now, to take on a full body off restoration and modification of a SWB w460 G230 and put a M119 motor in it.
I have been periodically posting my progress here: 1980 230g Body-off frame restoration - Club G-Wagen Forum
If you read the last post I thought I had blown my motor, but it actually turned out that my breather was blocked causing my crank case to pressurize and foam the oil.

I drained it and replaced the filter and refilled it yesterday.
Started it up and it ran perfectly…..until the temperature rise. This has been the issue I have been fighting with since I first got it up and running (which you can read on my other posts was quite a saga).

Couple of questions I have for you if you’d be inclined to try and help me answer:

1. Due to space constraints I had to install two electric pusher fans with 1,600 CFM each - is this enough? (I thought that the M119 needed 2,500CFM to stay cool at idle)

2. I have read the post regarding thermostats several time and am confused. Isn’t the thermostat supposed to open to allow cooled coolant to circulate through the system? If so why is it that the top portion of my water pump housing at the short horizontal hose gets to 105c but the portion just below where the thermostat is located is only 60c? This seems to not be allowing the thermostat to open.

The upper radiator hose was at 88c, lower hose at 44c, coolant reservoir showing coolant at 74c.

I am wondering if I have something plumbed incorrectly and frankly am just confused right now.

She idled for almost 50 mins before hitting 110c and sat at 109 for 18 of those 50 mins. I shut it down at 110c.

Any ideas and recommendations to get her to cool down would be greatly appreciated.

 

[gsxr]

110C at the gauge is not normal.

Is the thermostat OE/OEM and either new or recent? Will the engine cool down when driving? Idling for nearly an hour is not normal service.

Welcome to the forum!

 

[EHKO]

the water pump was replaced by me about two years ago as it was leaking badly (likely due to the motor being moved around quite a bit from the hook point on top of the water pump) upon start up.
I did test the thermostat by dropping in a boiling pot of water and it does open. I did not verify exactly what temp it opened.
I can’t drive the vehicle yet because I can’t put it on a dyno and tune the computers until she stays cool at idle.
The motor is stand alone on a Links Xtreme ECU with a separate TCU for the 7.226 transmission.
Thanks!!

 

[EHKO]

Additional question for the M119 gurus. Is there a kit to add an oil cooler. My radiator, which came out of +2003 G500 has the fittings for what appear to be both steering (larger fittings on driver side) and transmission (smaller fittings on passenger side) cooler built into the radiator. The smaller fittings are only about 18” away from my oil filter housing.
I have read several places that an oil cooler can potential lower engine temps by approx 10c.
Thanks all!!!

 

[gsxr]

the water pump was replaced by me about two years ago as it was leaking badly (likely due to the motor being moved around quite a bit from the hook point on top of the water pump) upon start up. I did test the thermostat by dropping in a boiling pot of water and it does open. I did not verify exactly what temp it opened.

The opening temperature AND the stroke length are both critical. If the thermostat is not new, replace it with new OE/OEM.

I can’t drive the vehicle yet because I can’t put it on a dyno and tune the computers until she stays cool at idle.
The motor is stand alone on a Links Xtreme ECU with a separate TCU for the 7.226 transmission.

Ohhhhhhh. Non-factory ECU could be causing issues as well, depending on the mixture control at idle.

Additional question for the M119 gurus. Is there a kit to add an oil cooler. My radiator, which came out of +2003 G500 has the fittings for what appear to be both steering (larger fittings on driver side) and transmission (smaller fittings on passenger side) cooler built into the radiator. The smaller fittings are only about 18” away from my oil filter housing.
I have read several places that an oil cooler can potential lower engine temps by approx 10c.
Thanks all!!!

The M119 had an external engine oil cooler on some models/regions, like the 500E (except in USA/Japan). Some of the parts may be NLA so it could be a challenge to retrofit. Don't expect any reduction in engine coolant temps under normal driving. The oil thermostat doesn't open until the engine oil is over 110°C. See the M119 engine manual, job 18-1110. An oil cooler is always a good idea but it will NOT lower your coolant temps at extended idle.

 

[yevgenievich]

One thing beside the plumbing and getting the coolant to flow correctly, is if it is idling lean, it will run hot. Only mentioning because of stand alone ecu.

 

[EHKO]

I appreciate all the answers provided. Thank you!
I do understand that my ECU may be running a bit lean, but it should have no affect on a mechanical thermostat. Everything about the cooling system is mechanical. The confusing part to me is why the coolant temp on the gauge and by thermometer would read 105c at the top of the water pump housing, but the temp at the thermostat housing is at 60c. Seems that there is some sort of air pocket created right at the thermostat and coolant is running past it and not heating it at all.

 

[EHKO]

So the marking on my thermostat lead me to believe it’s OEM BTT or Behr. However, I just checked it again in a pot of water with a thermometer to see exactly when it opens and it’s a 90c thermostat vs. what I thought was an 80c. That said, seems like it would have opened either way. Scatching my head!

 

[gsxr]

The thermostat should start opening at 80C and be fully open at ~95C. However, if it does not FULLY open (maximum stroke) it will not close off the port which allows hot water to circulate. This is why you want to start with a new thermostat, before further investigation. The Mercedes cooling system works differently than many other marques, the t-stat is NOT a simply flow valve in line with the lower radiator hose. Look at the cooling system flow diagrams in the factory manual.

 

[EHKO]

I have studied the components and they are a bit daunting to understand. To be clear, when the t-stat opens the smaller plate at the “bottom” extends and closes off the flow straight through the pump and the “upper” plate open then allowing the lower radiator hose to begin flowing into the pump? It looks like it would then just be in a loop but I can’t really picture it in my head in 3D.
Any chance you could share the flow diagrams with me please?
FWIW- I already ordered a new pump from the dealer and removed the “new old” one this morning. I will order a new t-stat as well. Should I consider a 75c t-stat?
Thank you for the input!!

 

[EHKO]

Some additional information for those that may have more knowledge than myself as I continue to figure this beast out.
It looks like I am running almost perfect on my mix as I have an average 0.979 Lambda. Here is a shot of my last run just before shutdown when coolant hit 110c.
Admittedly not knowledgeable about this software yet, but am trying to learn. If any of the values outside of engine coolant temp (ECT) and intake air temp (IAT) look off please let me know. The IAT is being affected by the overall engine temp as it’s an open throttle body as I run it for now.
Thank you!!

 

[gsxr]

I have studied the components and they are a bit daunting to understand. To be clear, when the t-stat opens the smaller plate at the “bottom” extends and closes off the flow straight through the pump and the “upper” plate open then allowing the lower radiator hose to begin flowing into the pump? It looks like it would then just be in a loop but I can’t really picture it in my head in 3D.

That is correct, The coolant bypasses the radiator when the t-stat is fully closed, and 100% goes through the radiator when the t-stat is fully open. In between, there is a mix.

Any chance you could share the flow diagrams with me please?

I can't find the M119 diagrams, but the system is nearly identical to the M117 engine, diagrams are here:

https://www.startekinfo.com/service/download-document/outside/11883/PROGRAM/Engine/107/M117_56/20-005.pdf

FWIW- I already ordered a new pump from the dealer and removed the “new old” one this morning. I will order a new t-stat as well. Should I consider a 75c t-stat?
Thank you for the input!!

Any lower-temp thermostat won't improve cooling or reduce operating temps above the fully-open temp rating (94°C). I'm not aware of a factory OEM thermostat below the standard 80C... I think one exists but it isn't going to help if you are seeing over 110C idling. Switching points are in this document:

https://freescruz.com/.priv/W124/w124CD1/Program/Engine/119/20-0020.pdf

 

[EHKO]

Any idea why my t-stat isn’t opening? Again, I tested it and it is opening and is a 90c start to its opening so I think I have the wrong one….,but it still should have opened, no?
BTW- Thank you for the assistance, it is appreciated.

 

[EHKO]

Just curious, wondering why the S class has the reservoir line coming off the water pump and the SL class has it coming off just above the upper radiator hose off the radiator housing. Anyone know why they are different?
1st pic is S class
2nd pic is SL class

 

[gsxr]

I don't know why, but the function is essentially the same. The W124 also has the fitting at the radiator, like the R129.

 

[EHKO]

While reviewing the logs from my last run it appears one side (not sure which one yet) is getting much hotter than the other, like 500 vs 750. The 500 degree side sensor says “calibrating” the entire time while the 750 degree side says “operating”. As I understand, these sensors, taken together give the Avg Lambda and need 600 degrees to begin reading. If one side isn’t logging properly I’m getting a false reading. I have read that the cam timing being off on one side can cause this. I have pulled the cams off twice (once while doing the head gaskets) but both times I clearly marked the chain and the cams and made sure they all went back the same and all four pinned. Seems really weird that everything seems to check diagnostically and the engine sounds like it’s running super smooth for my timing to be so far off as to have one bank being much hotter than the other. Once I have the new water pump and t-stat installed I’ll start it back up and shoot each side with my thermometer. If anyone out there has had this same experience and resolved it, please let me know what was wrong and how you resolved it.
Thanks all!!!

 

[gsxr]

Did you rotate the engine 720° and verify that all 4 cams still pinned at close to 45° ATDC?

Another quick test is to energize each intake cam advance solenoid at idle. When advanced (energized), the idle quality should become poor, and smooth out when de-energized.

 

[EHKO]

I will double check them as you state, just more copper washers.
Currently my cam adjusters are disconnected. I’m having an issue with my wiring I need to sort out, I’m getting back feed when they are connected, it’s the only wiring issue I’ve had. The guy who set up my ECU also built my harness, when I have the time I’m going to have it fixed. I think I can energize them externally though and check.
Thank you.

 

[EHKO]

Quick update: I torn down the front end and pulled everything apart and swapped the water pump with an authentic MB pump and thermostat (older style that was original to motor because I have my trigger wheel sensor mounted to it). My motor is now running at idle at 88-90c in 100f summer heat and even drops temp when accelerator is opened!! I ran it for two hours and the needle was rock solid.

Have been working through my TCU wiring and hope to have it rolling next week. If it will run through the gears (fingers crossed) it’ll be time to put her on the dyno!!!

Thanks to everyone who chimed in.
Have a great weekend!!

 

[Alphasud40]

I am late to the party on this discussion and there were 2 possibilities with your situation. Rotation of the coolant pump. Does your engine have a different belt routing? And 2nd air pockets won’t allow the thermostat to open if the body of the thermostat sits in an air pocket. Some special circumstances require a tiny bleed hole in the thermostat if the OEM bleed is not working or the thermostat doesn’t have one. Glad you got it sorted.

 

[Pat]

Here is my overheating experience. The fan clutch can seem to be operational when it is not doing what it is supposed to do. My engine heat gauge would slowly increase at extended idle as in stop and go traffic, at a certain temperature above 100 but lower than the red zone, the electric fans would come on and immediately the temp gauge would start to go down. The temp gauge was always at or below 100 when travelling (ie good air flow through the radiator). After I replaced the fan clutch, the temps always stay below 100 and the electric fans only come on when I run the ac.

 

[gsxr]

After I replaced the fan clutch, the temps always stay below 100 and the electric fans only come on when I run the ac.

What brand fan clutch did you install?

The electric fans run on low speed based on AC refrigerant pressure only.

The electric fans run on high speed based on coolant temp, and normally turn on at 107°C.

 

[Pat]

I had a uro on it but replacing with a borg-warner. the uro worked but it doesn't seem to know when to relax and disengage. I haven't checked with the dealer for an original equipment clutch. Thanks for the EZL disconnect tip a post or two back.

 

[gsxr]

OE fan clutch has been NLA for years (and, nobody wanted to shell out the $600-$800 back when it was available).

Many aftermarket clutches either never disengage (this is not good), or disengage at a higher RPM than stock (not ideal, but acceptable). Some also remain engaged at low air temps, which is annoying (noisy, and reduces economy/power). AT the moment, I don't know what clutch brand to recommend.

That said: don't use ÜRO or any no-name clutch. Years ago, a forum member posted photos of a cheap eBay-sourced clutch exploding and destroying the radiator within something like 50 miles after the clutch was installed. And now the radiators are NLA too, so it's a double whammy. Lots of risk involved here.

 

[Alphasud40]

I had luck with Hella/Behr For both the M103 and M113 applications.