cali315

Hi guys,

04 clk 500 new thermostat and temp sensor about a month or two ago.. Rad is only a few years old (replaced by previous owner) secondary cat and muffler delete.

What is normal operating temp? I have been sitting at 90+-100 never over though. The weather has been cooler 5-10 degrees Celsius (this also was happening in the winter at -10 to -20 Celsius)

The reason for this post is I never really payed attention to the temp gauge when I got the car until a few months back when The temp sensor went.. Today I found a picture from last summer.. 25+ Celsius and the temp gauge (while cruising) was dead middle at 80.. Why now am I experiencing warm temps? Especially in the cold weather!!! I'm 99% sure the fan still works as it was when I had my temp sensor issue! I believe the shop that did the thermostat topped up with normal green coolant.. (Not happy about it) but I dont think this would have anything to do with it?

Any input would be greatly appreciated! I was planning on having my shop now (MB specialist) do a coolant flush and check the thermostat temp and make sure the last shop put the correct one in..

Any thoughts?

DRACO

What color is the fluid?

cali315

Originally it was the yellow ish colour.. Which I understand was the older MB coolant.. Now there's the bright green crap in there.. I didn't think so check after the thermostat was installed.

Could it be the old temp sensor was acting up last summer then finally kicked the bucket this January? Seems like a long time though?
Or
Could the thermostat that was installed has a higher degree release? Or could it be something totally different?

Rudeney

90C is normal. The coolant should be orange - get some Xerex G05 and flush it.

DRACO

+1, Oh Poop, get the green crap out of it, Get proper MBZ or Zerex fluid.

Flush until all the green is out, YOU CAN NOT MIX the fluids, it will turn into Gelatin.

cali315

Thanks guys! I just freaked out because of seeing the pic of last summer in the middle of summer at 25 Celsius and the temp sitting at 80..
I will be flushing the system and putting new mb coolant in for sure!! I always like to run oem fluids! They come that way for a reason!

Thanks again! Appreciate the insight

Patton001

Keep in mind that thermostats come in different temp ranges. Did this start after the install of the new stat? Is is possible you put the wrong temp stat in? Just a thought.

cali315

Yes I am aware they do! And I thought this may be quite possible but even online most of the thermos I find have a temp of 87 Celsius I believe off the top of my head! I mean I'm sure it's possible they could have? Anyone else think? I usually do small jobs like that myself but with work it's been tough now! Probably should start again though..

I'm going to flush with new coolant maybe I'll pull the thermostat out and check the degree rating on it.

I was afraid of what summer would hold for her if she was running higher temps in the cold weather! If these temps are fairly normal though I will just keep on driving her!

Thanks again to all for your opinions and help! Much appreciated!

cali315

Hey guys,

Bit of an update.. Complete coolant flush done and replaced with oem coolant!!

Today is 14 Celsius and my car is consistently running just under 100 degrees.. (One tick below) no matter driving or sitting.. However when sitting it sits at 100 then will drop down that 1 tick when moving.

I'm lost as to what is going on.. Could the new thermostat be crap? Could my water pump be shot? (I don't see any leaks, hear a faint grinding noise when the car is running and I place my head over the pulley area.. Could be any pulley though) could the new temp sensor be reading wrong? I'm absolutely lost! Last year in the middle of summer (30 Celsius) this car ran at 80 degrees why now am I running at 100!!!!! Also, I'm not loosing coolant either!

I ran the car for 5 mins with the AC on full blast.. Shut off for 5 mins, turned ignition on car was at 100 or the tick below again. Started the car and it didn't move... Is this the water pump kicking the bucket??

Any input please would be extremely helpful!!!!!!

Rudeney

It certainly could be the water pump. Given the low price (about $70) and being a fairly easy DIY job, I might just "throw a part at it" and see.

MacVidMB-V8

Might be worth verifying the gauge accuracy.

Rudeney

The gauge itself is electronic, so it could be a bad temperature sensor. And that would be easy enough to check with an infrared thermometer. Definitely worth doing!

cali315

Thank you guys very much!
With a new thermostat and temp sensor I may start there to see if by any chance one is faulty.. As this could be a very possible thing? Another thought.. Could I have air in my system?

However, last night probably about 12 Celsius outside in town driving the car stayed in the 85-90ish range which was perfect! When I got on the highway cruising at about 120-130 km/hr I notice it stayed pegged with no movement at about 90 maybe a touch higher I'd say... Still better then the steady 100 it has been showing lately (during the day at 15+ celsius) Do these symptoms show anything I may not be aware of? I always thought those were thermostat or water pump symptoms but would be happy to hear your thoughts again!

Thank you again! This is greatly appreciated!!

gixxerboy

is the fan operating properly? It may be on but at a slower speed?

cali315

fan is running properly! Speed is fine! Pretty positive there is no change in the speed!

cali315

Hey everyone another update..

I took my car out of town today (20 Celsius out) mixture of country and highway driving and I'm fluctuation between 85-90 oC.

In town driving I'm always staying 100 or the tick under.. Would this clarify my water pump is the problem and not circulating enough? Or is this relatively normal? I know these engines run hot however I just want to be 100% sure and would rather have something fixed now before it becomes a bigger issue..

Thanks again!

gixxerboy

thats normal to me

cali315

Ya? Ok maybe I'm just over thinking things! I never payed attention to the temp gauge when I got the car! This year I had an issue where I was running high temps.. Over 100 and that's when I started to watch it! After changing the thermostat we determined then it was just the temp sensor! Now I've always watched the temp gauge! Back in highschool I had a Lincoln LS that would always overheat and I just did not want that again! Lol

I appreciate everyone's input and posts! I will put my mind as easy for now! I'll have a peak at any pulley play or leaks when the oil change gets done in the coming weeks (right now there's no a leaks nor pulley play)

Thank you again to all!

Azeem

Thanks for sharing your experience. The car was low on refrigerant. I had filled her up today and Driver side is now cooling properly. My AC is definitely has a leakage as I recall filling the refrigerant a couple of months ago but the car was barely used during this period. Let's see how long this fill up last. I will take the car to the dealership to check it thoroughly for leakage. From your experience do you know how much refrigerant the system can hold in lbs?
Thanks again.