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1994 Mercedes E320
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150 Posts
Discussion Starter · #1 · (Edited)
high temps

i have an 86 300e. about a month ago, some may remember me talking about my car being hot after an SF to LA drive. it had run fine, until now that is. today, after driving from pomona to bellflower (20 mi) and then on the way back, the car started running at 105 C.

it usually got warm after staying in traffic, but once i started going it would cool down again and run at about 85 C.

ut this time, it stayed at 105 C and maybe dipped down to 98 C once. it stayed warm the whole way, so i ask, what could this problem be. i hope it is the thermostat, because it is cheap, but could it be something worse?
 

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1976 BMW 2002. 1991 250TD. 1995 E320. 2018 Honda Africa Twin
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2,712 Posts
i dont understand how running at 105 is a problem.

thats within the range of operation temperatures for the engine. i could swear this has been gone over in every temperature thread.
 

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1994 Mercedes E320
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150 Posts
Discussion Starter · #5 ·
yeah but constantly, and with no significant raise in outside temperature. it just took me by surprise. the car was running at 85 C and then all of the sudden it was running hot and not cooling down. this is also a car that has always run at 85 C since i have had it, and now it has been warm.
 

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1976 BMW 2002. 1991 250TD. 1995 E320. 2018 Honda Africa Twin
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2,712 Posts
if its a sudden, recent development, then you have a recent problem. it could be anything.

do the basics first. flush your system.
refill with water. run to operating temps.
flush again.
refill with h2o and coolant

if the temps stay up, you have to start thinking thermostat, water pump, pipes, sensors, blocked fins on radiator etc.

in light of the recent spike in temperature here in so cal, were you using your AC more than you did, say two months ago? if your AC needs charging it could be on all the time/ more frequently and causing the temps to go up. if your car needs a tuneup and you turn on the AC the extra load could cause the temps to go up. it could be the oxygen sensor. transmission. who knows

its really not a simple, oh, check this question. like we do with the OVP for unexplained electrical maladies.
 

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1994 Mercedes E320
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150 Posts
Discussion Starter · #8 ·
my water pump is new and i don't have AC (broke and never got it fixed) tranny is rebuilt at 220,000 after it stopped shifting up to 4th gear. car has 20,000 since.the pipes are all like new. no leaks either. i will flush the system when i go home, at CAL POLY, access to a hose is limited and the quarter is over in 4 days.

as for the aux fans, they come on at about 110 C but i wasn't touching that temperature, so in this case, they have not been coming on.

i know it isn't simple, and i thank you for your answers. i just hoped the symptoms sounded familiar and that it wasn't something terrible on its way.

again thank you.
 

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1976 BMW 2002. 1991 250TD. 1995 E320. 2018 Honda Africa Twin
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2,712 Posts
so i say go to one of those self service car washes, open your hood, and let her have it with the high pressure hose. clean out any debris in the fins

try to not directly point the hose at electrical stuff.

also check the condition of the windshield washer bottle. when mine had a problem it led to immediate higher temperatures
 

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68 280 SEL, 89 300TE
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906 Posts
I has the same issue with my 300TE, turned out to be the thermostat, then two weeks later/ago my water pump crapped out on me. Just fixed that yesterday in my friends yard where it died on me, never a fun job, but at least I didn't get stranded on the hwy or the pass. BTW, replacing these pumps on the M103 is a biatch, I have done a number of MBZ pumps, and this was probably the most involved to date.

So, in conclusion, try the thermostat, it only takes 5 min max to change, but make sure to tighten the 3 bolts evenly or else you can crack that aluminum housing/cap.
 

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300CE
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92 Posts
I had exactly same problem few weeks ago and brought my ce to figure out. Finally there was a bad circulation in radiator due to the clugs. I've changed radiator and thermostat and now it runs normal. I mean normal is 85-90 in running and above 100-110 when there is a traffic with AC on. Remember our 124 is a hot temp. running machine.
 
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