Temp issue
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glk 350
Temp issue
I have a 2010 GLK350 with 80000 miles and I am having temp spiking issues. I have owned the car a little over 2 years and about a year ago I replaced the thermostat and since have had no issues until about a week ago when headed home and the temp warning came on. The gauge was spiked at 120 so I started to pull over and by the time I got the car stopped the temp dropped to normal temp of about 88. Drove the rest of the way home with no fluctuation at all.
it did it again yesterday but with no warning light so I parked and left it running. I checked the upper and lower radiator hoses and while warm they were defiantly not overly hot and I did not feel a ton of heat coming off the engine. I got back in and gauge was still spiked so I turned it off and sat for about 2 minutes and started it. And temp went directly to 88c.
Happened again today on my wife’s way home and by the time she pulled over it had dropped again. I am thinking that with the speed it drops it is a faulty temp sensor but I want to see if anyone has seen this issue and if so what you did to fix it.
it did it again yesterday but with no warning light so I parked and left it running. I checked the upper and lower radiator hoses and while warm they were defiantly not overly hot and I did not feel a ton of heat coming off the engine. I got back in and gauge was still spiked so I turned it off and sat for about 2 minutes and started it. And temp went directly to 88c.
Happened again today on my wife’s way home and by the time she pulled over it had dropped again. I am thinking that with the speed it drops it is a faulty temp sensor but I want to see if anyone has seen this issue and if so what you did to fix it.
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glk 350
If I recall from changing the thermostat, there is a sensor on the thermostat housing and I think there is another on the engine block. I am assuming it would be the one on the engine block that controls the thermostat. Is that correct or am I way off?
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2013 glk 350
120c is 250 Fahrenheit, your expansion tank would have boiled over, did it? Are cooling fans running? Do fans come on when you turn in the AC? 120 c can ruin the motor , I wouldn’t drive it .
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glk 350
no boil over and fan is running normally. If anything the fan seems to be running too fast. I just tried it again in the driveway at idle. Came up to about 90 and sat for about 3 minutes with little to no fluctuation and then jumped to 110 and another jump to about 118. I got out while still idling and grabbed the upper radiator hose and it was warm but not so hot that I needed to let go. Nowhere near 250f. The lower hose was also warm but significantly cooler than the upper. Got back in and it was still registering 118c so I turned it off and shot a laser temp sensor on several places on the engine, no readings higher than 189f. After about 2-3 minutes of taking readings I started it and it went immediately to about 95c and after about 3 seconds later dropped to typical 90c.
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MBWorld Fanatic!
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From: Northern NJ
GLK 350 / Porsche 993
I think air bubble would have presented an issue much earlier.
Does the big fan come on? Anything blocking it?
Did you replace water-pump too when replacing t-stat? Is the belt and all all pulleys spinning good and rotating everything?
You, definitely don't want to overheat the engine like this.
Does the big fan come on? Anything blocking it?
Did you replace water-pump too when replacing t-stat? Is the belt and all all pulleys spinning good and rotating everything?
You, definitely don't want to overheat the engine like this.
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glk 350
I think air bubble would have presented an issue much earlier.
Does the big fan come on? Anything blocking it?
Did you replace water-pump too when replacing t-stat? Is the belt and all all pulleys spinning good and rotating everything?
You, definitely don't want to overheat the engine like this.
Does the big fan come on? Anything blocking it?
Did you replace water-pump too when replacing t-stat? Is the belt and all all pulleys spinning good and rotating everything?
You, definitely don't want to overheat the engine like this.
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glk 350
Ok just did the infrared test on the thermostat housing and when the upper hose felt firm (thermostat opened) the reading was consistently 83c and temp gauge was showing about 85c. Let it idle for a few more minutes and it stays steady Then the cooling fan kicked up to super high speed and temp gauge jumped to about 108c and housing steadily rose to high of 98c while the temp gauge climbed to 120. Went back to check temp at housing and stayed at 98 until I heard the fan slow down and housing temp steadily dropped to 93c and temp gauge dropped back to about 90 (normal operating temp). Both gauge and housing temps stayed steady for 5 more minutes at idle with outside temp about 90f before shutting it down.
Does this give anyone any new ideas? There was a temp fluctuation but nowhere near 210 so I am still thinking sensor. Thoughts anyone?
Does this give anyone any new ideas? There was a temp fluctuation but nowhere near 210 so I am still thinking sensor. Thoughts anyone?
Out Of Control!!
Joined: Sep 2018
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From: unbegrenzt
2017 GLE350 4MATIC
Cooling systems are not hard to fix. You haven’t thrown parts at it yet, have you? Excluding the t’stat. You need to start taking action besides squeezing hoses.
Step 1 - bleed the system and refill with a full fresh charge of coolant.
Step 2 - operate the vehicle
Step 3 - report your findings here
Step 1 - bleed the system and refill with a full fresh charge of coolant.
Step 2 - operate the vehicle
Step 3 - report your findings here
Thread Starter
Newbie
Joined: Aug 2018
Posts: 12
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glk 350
Cooling systems are not hard to fix. You haven’t thrown parts at it yet, have you? Excluding the t’stat. You need to start taking action besides squeezing hoses.
Step 1 - bleed the system and refill with a full fresh charge of coolant.
Step 2 - operate the vehicle
Step 3 - report your findings here
Step 1 - bleed the system and refill with a full fresh charge of coolant.
Step 2 - operate the vehicle
Step 3 - report your findings here
Might be my own ignorance but how could coolant cause symptoms like this’d it wasn’t low? ......then again this is my first MB and this far seem to be a different animal.
Out Of Control!!
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From: unbegrenzt
2017 GLE350 4MATIC
I don’t think you have conclusively determined that the coolant isn’t low. Some (most?) M-B coolant systems need to be have air purged using a prescribed procedure. Consider the V12 cooling system with an auxiliary burp bottle on top of the engine. The cooling systems are designed with local high points where air can be trapped if the coolant is mist a little low.
Your description of symptoms is consistent with low coolant. Toyotas are also sensitive to small changes in coolant level, although their systems are easy to fill and to maintain full.
Drain, bleed and refill the system with a full fresh charge of coolant. DIY or have an independent shop do this.
Your description of symptoms is consistent with low coolant. Toyotas are also sensitive to small changes in coolant level, although their systems are easy to fill and to maintain full.
Drain, bleed and refill the system with a full fresh charge of coolant. DIY or have an independent shop do this.
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Newbie
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glk 350
Update..... swapped out the coolant temp sensor on the back of the engine and the problem persisted. Coolant flush and fill....yea that didn’t work either! Replaced the thermostat/housing/sensor Combo that I had replaced a little over a year ago and voila, running perfect! Not sure why MB insists on trying to reinvent the wheel, mechanical thermostats have been working great since 1900 but some engineer decided they should add a sensor and charge 1000% more for an extra part that’s bound to fail!
