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Everyone needs to keep in mind that this is an M104, not an M112/113. There is a big difference; I've owned both. Furthermore, the 71 degree reading doesn't make sense. We've been in a major heat wave here in Virginia, with temps in the high 90's to over 100 degrees. Only the OP can explain.
We had a terrible storm last night in Northern VA that dropped them temp to the low 70s, these pictures were taken after the car had being sitting for two hours and I was on the road for about 8-10 minutes (stopped 2-3 times for about 30-45 seconds each time). I just feel like something is off, I do hear you that the M104 runs hot. I also have a inkling that is could be a coolant flow issue. Just not sure where to start here.
Thanks for all the help guys! I do not feel comfortable fixing the A/C and running it when the car seems to be acting weird like this.
OK, that explains the ambient reading. First, I don't think you should be worried about damaging the engine as long as it doesn't go over 120. Please answer:
1) Does it hold at 95-100 in traffic on a hot day? You did say the aux fans seem to be running properly.
2) What temp does it settle at cruising at highway speed on a hot day?
3) Run the fan clutch test. I am not sure about your C36. Some M104 cars had a cable operated throttle unless equipped with traction control. The C36 may have had the electronic throttle standard. Figure out how to raise the engine speed from the engine compartment and run the test. Or have someone operate the throttle from inside the car while you observe. It should be fairly obvious if the clutch is engaging.
Let us know the answers to the above. The only way to diagnose this is to go step-by-step.
Hey guys, while we're on the subject, would it not be more beneficial to remove the clutch fan and install an electric one?
M-B did exactly that when the updated cars came out, at least on the I-4 and V-6 cars. They did it with a giant fan that covered the whole radiator and a controller that varied fan speed according to load. It is a far better setup IMHO. It addresses the issue of airflow without adding a big drag on the engine (like the viscous clutch does) while simultaneously reducing fan noise. On our 1995 C280 with the M104 I always felt the fan noise was excessive. I rarely heard the fan on our 2000 C280. But M-B didn't do that on the C43, maybe because the electric fan unit is quite deep and that would create space problems with the V-8. Aftermarket solutions lack the variability of the M-B setup and are not a great solution, IMHO.
Back to the OP, I thought of something that happened a number of years ago on our M104 and I believe the setup on your car is the same. On the thermostat housing there are 3 temp sensors. IIRC, 1 is for the gauge, 1 is for the aux fans (both are on the top of the housing) and 1 is for the ECU (round plug on the side of the housing). I sold all my manuals when I sold the cars so I am working from memory, but I recall changing the sensor for the gauge when I was getting high readings. The manual has the resistance curves for the sensors so it is easy to check if the sensor is out of range. The sensor isn't expensive or hard to change and it might be worth a try.
OK, that explains the ambient reading. First, I don't think you should be worried about damaging the engine as long as it doesn't go over 120. Please answer:
1) Does it hold at 95-100 in traffic on a hot day? You did say the aux fans seem to be running properly.
2) What temp does it settle at cruising at highway speed on a hot day?
3) Run the fan clutch test. I am not sure about your C36. Some M104 cars had a cable operated throttle unless equipped with traction control. The C36 may have had the electronic throttle standard. Figure out how to raise the engine speed from the engine compartment and run the test. Or have someone operate the throttle from inside the car while you observe. It should be fairly obvious if the clutch is engaging.
Let us know the answers to the above. The only way to diagnose this is to go step-by-step.
Well Vince, I think you might be onto something here. While I was waiting for a cab yesterday I opened the hood and rev’d the engine to 3k while the car was hot, I am almost certain I heard the speed increase. I still need to verify with another person when I get back from my trip. I was kicking myself a bit, so I continued to check other components, this is when I realized what my problem might be. My coolant reservoir was not filled to the top like it was a few months back after a flush (it has dropped to about ¾ mark). I rarely drive the car; this is prob after 800-1k miles of driving after the coolant change. When the coolant was changed my mechanic performed a pressure test and it was holding just fine, I was a little concerned it might be a head gasket because the car was operating like it has back then.
I have all the records on my car since new, there was a new gasket installed at 52k miles back in 10/98. I inspected the coolant tank and oil cap for any contamination yesterday, I could not find any signs of things getting mixed. I get the oil changed every 4.5-5k miles, the oil light typically comes on around 3.5-4k miles after an oil change, and it has been like this since it hit 125-130k miles. I think my best option at this point is to pay 1-1.5hr labor to have it looked over. I am not just about to start throwing money at parts after discovering the loss of coolant. The water pump was changed around 125k. I think the radiator is the original. Coolant cap was swapped at the time of the coolant flush.
I get back on Monday evening, I hope to get it booked in for a diagnosis next week and I will post back with the results. You guys are very helpful! Thanks again for everything!!
The head gasket replacements on the M104 were to address oil leaks. There were a couple upgrades to the original gasket before the final solution was found. My M104 had the gasket changed twice (by M-B); the final version part was in the car for 190,000+ miles without problem.
I think you are making the right decision to get a professional diagnosis before throwing parts at the problem.
The head gasket replacements on the M104 were to address oil leaks. There were a couple upgrades to the original gasket before the final solution was found. My M104 had the gasket changed twice (by M-B); the final version part was in the car for 190,000+ miles without problem.
I think you are making the right decision to get a professional diagnosis before throwing parts at the problem.
This is my fear, the gasket was done back in 10/98. Do you happen to know the amount of coolant loss or oil consumption one would experience from a gasket gone south? Does the car typically fully overheat? I had a misfire a while back that also seems to be a symptom, it only lasted one night (800-1k miles ago) and has been fine ever since. I sometimes see a puff of white smoke when I start the car in the morning, it does not worry me too much as I am used to it on my 996tt after it sits overnight or for an extended period of time.
The internet can be a scary place when trying to diagnose these problems, I do not want to jump to conclusions before it gets looked over. Still a bit baffled how it passed the pressure test, it sounds like there could be other tests that would need to be performed to fully verify. This car has been so good to me, I want it to get what it needs.
I would not worry about the head gasket unless you are using a lot of coolant (which from your earlier post is not the case) or there is oil in the coolant reservoir. The problem with the earlier gaskets was external oil leakage, mostly at the outboard rear corner of the head. The second gasket in my M104 was done in '98 and was still tight last year when the car was totaled by a careless driver. Like I said, that was some 190,000+ plus after it was replaced.
In fact, I am not convinced, at least at this point, that your car is actually running too warm. The sensor needs to be looked at to make sure the dash reading is actually correct.
Regarding of coolant; MB always using "Green Ethylene glycol coolant", some other makers uses "Pink/Red coolant"...!
anyone knows what the difference between them..?!?!?
ZAYED,,
Before the flush it was Pink/Red, but now I have the updated coolant from MB which is a Blue/Green color. Another member told me this updated coolant caused his water pump to leak a week after the flush. Not really sure about the difference though.
I would not worry about the head gasket unless you are using a lot of coolant (which from your earlier post is not the case) or there is oil in the coolant reservoir. The problem with the earlier gaskets was external oil leakage, mostly at the outboard rear corner of the head. The second gasket in my M104 was done in '98 and was still tight last year when the car was totaled by a careless driver. Like I said, that was some 190,000+ plus after it was replaced.
In fact, I am not convinced, at least at this point, that your car is actually running too warm. The sensor needs to be looked at to make sure the dash reading is actually correct.
Okay thanks, the coolant loss is minimal. I know the MBs from this era tend to run quite a bit hot when compared to most cars.
The car will be looked over next week. I appreciate all the help from everyone; i am glad to see this section of the forum is very active!
My 36 never gets over this unless something was wrong. Only time I have ever seen it get to 100 is when the top half of the thermostat failed. Picture was take with AC on while running around town and then idling in parking spot.
I appreciate all the help guys! Very helpful and responsive section of the site here!! I hear you Vince, what you're saying does make sense to me. It was quite humid here today, I took these pic's and I was barely sitting in any traffic when it was registering these temps. Do you think this is normal? I will try the test you recommended, it was raining all day and did not have the chance to rev it up like you told me to. Please let me know your thoughts:
On the temperature question, we are starting a hot dry spell which should extend over the next days and probably next week too.
First photo shows engine temp when running at stable speed (driving with the tempomat) on the highway.
Second is in city stop and go traffic.
Hope that helps but you are running a bit higher than me. Influence of extra humidity level perhaps?
I looked at doing this a while back, but the C55 fan looked too deep for the C43, would you know how thick the unit is?..I thought maybe could remove the A/C fans and push radiator and condenser forward a small amount to allow clearance?..it would need some custom works
Cheers!
Originally Posted by cm60k
Done that Electric fan with previous "W124 E500 & R129 SL55", (5) years ago, it's great mod.,
used C55 850W fan, starting from 75c & 2 speed controlled by 2 Relays,,
(of course Electrical guy done that for me, i'm not that sure how he done it & also i'm not good with Electrician)..
Easy check for your viscose fan is a news paper rolled up .At running temprature pop it in the fan if it stops its no good .Have you done this yet?
Not necessarily. The clutch allows the fan to freewheel with very little resistance until the bimetal spring senses excessive temperature coming off the radiator. If you do the newspaper test shortly after a cold start the fan will stop quite easily and the clutch could still be good. I've actually stopped these fans by hand (with a heavy leather glove on) when the engine is cold.
To perform the newspaper test the engine should be fully warmed up on a hot day after a good drive, A/C on, aux fans blocked by a sheet of cardboard.
Not necessarily. The clutch allows the fan to freewheel with very little resistance until the bimetal spring senses excessive temperature coming off the radiator. If you do the newspaper test shortly after a cold start the fan will stop quite easily and the clutch could still be good. I've actually stopped these fans by hand (with a heavy leather glove on) when the engine is cold.
To perform the newspaper test the engine should be fully warmed up on a hot day after a good drive, A/C on, aux fans blocked by a sheet of cardboard.
It was determined that the fan clutch is definitely faulty, I will be replacing this part next week. It spins 15-20 revolutions now when the car is shut off and a piece of tissue could practically stop it when it hits 100c. I installed a new Behr thermostat last week w/ no results.
Should I also change the bearing bracket, does this typically go bad along with the fan clutch? I'm updating to the 9 blade fan too. Thanks for all the help on this one guys!!
It was determined that the fan clutch is definitely faulty, I will be replacing this part next week. It spins 15-20 revolutions now when the car is shut off and a piece of tissue could practically stop it when it hits 100c. I installed a new Behr thermostat last week w/ no results.
Should I also change the bearing bracket, does this typically go bad along with the fan clutch? I'm updating to the 9 blade fan too. Thanks for all the help on this one guys!!
Good. Take note of the sound before and after changing the clutch. When working properly there will be a pronounced roar from the fan. It sounds as though yours wasn't engaging enough to make that noise. In fact, I always found the fan noise from the M104 far too noisy.
Yes, change the bearing bracket. 100-125K miles is about all you can expect from one. I would also change the tensioner pulley and the idler pulley but then can always be done when they fail without too much difficulty.
06-18-2015, 03:41 PM
speeds 
