|
|
|
|
|
#1
10-25-2017, 08:54 AM
|
||||
|
||||
|
Thermostat Stuck Open? Need Confirmation
So I picked up my 300D this weekend and drove it home. I noticed that the temp gauge was riding a hair below 80*C. Not really concerned as the needle was still touching the 80*C line. I've driven it daily since and noticed the same.
This morning, we had one of our first mornings below 40*F. Car warmed up fine, but on the 30 min drive into work, I stopped getting heat. I cranked the ccu up to max and selected "auto". I got cold air that continued to get colder... that's when I noticed the temp Gauge was down below what I call the 60*C line (the mark between 80 and 40). I put the ccu on economy and the fan on low. Within 5 minutes I could feel heat coming back and the temp gauge went a mm or two above the 60*C mark, but no further. I'm thinking that the thermostat is stuck open and needs to be replaced. Your opinions? 
|
|
#2
10-25-2017, 08:59 AM
|
|||
|
|||
|
we'll definitely need to know what year and model you're driving. 60c-80c sounds about right to me. no heat issues are well documented in the forum archives. most likely a problem with the monovalve i guess.
__________________
Current fleet 2006 E320 CDI 1992 300D - 5speed manual swapped former members 1984 300D "Blues Mobile" 1978 300CD "El Toro"
|
|
#3
10-25-2017, 09:21 AM
|
|||
|
|||
|
Quote:
__________________
When cryptography is outlawed, bayl bhgynjf jvyy unir cevinpl.
|
|
#4
10-25-2017, 09:43 AM
|
||||
|
||||
|
If you drove for 10+ minutes and the coolant never got past 60, I think you have your answer. New thermostat time. It likely isn't stuck fully open, but certainly enough for the engine not to warm up. Low heat is only one of the problems. A cold engine will kill your power and economy and fail to drive moisture out of the lubricating oil.
__________________
Current stable: 1995 E320 157K (Nancy) 1983 500SL 125K (SLoL) Gone but not forgotten: 1986 300SDL (RIP) 1991 350SD 1991 560SEL 1990 560SEL 1986 500SEL Euro (Rusted to nothing at 47K!) Gone and wanting to forget: 1985 524TD 167K (TotalDumpster™) [Definitely NOT a Benz]
|
|
#5
10-25-2017, 10:30 AM
|
|||
|
|||
|
My 1984 300D was like that, usually running ~60 C on dash gage. I removed the T-stat and tested in a pot of hot water. It seemed to work until I made careful comparisons against a mercury thermometer, IR gun, and other T-stats. It opened a bit earlier and responded more sluggishly. Replaced it and the car has run 80-85 C ever since. I recall mileage went up. So, yes they can kind of work, but need replacing. My other opinion is that you should always tell us the year when asking a car question.
__________________
1984 & 1985 CA 300D's 1964 & 65 Mopar's - Valiant, Dart, Newport 1996 & 2002 Chrysler minivans
|
|
#6
10-25-2017, 01:20 PM
|
||||
|
||||
|
My bad... 1991. OM602
|
|
#7
10-26-2017, 08:54 AM
|
||||
|
||||
|
Zerex G-05 still the coolant of choice?
__________________
1991 300D 2.5 "Rocinante" 2002 Golf TDI "Teen Spirit" -------------------- 1984 300D 1966 Mustang I6 3sp 1985 Mazda RX-7 GSLSE 1982 Toyota Supra 1977 Datsun 280z 1971 Datsun 240z
|
|
#8
10-26-2017, 10:12 AM
|
||||
|
||||
|
Yes. Either get the pre diluted version or mix the full strength version yourself 50:50 with distilled water. You'll need one gallon of G05 and one gallon of distilled water.
__________________
The OM 642/722.9 powered family Still going strong 2014 ML350 Bluetec (wife's DD) 2013 E350 Bluetec (my DD) both my kids cars went to junkyard in 2023 2008 ML320 CDI (Older son’s DD) fatal transmission failure, water soaked/fried rear SAM, numerous other issues, just too far gone to save (165k miles) 2008 E320 Bluetec (Younger son's DD) injector failed open and diluted oil with diesel, spun main bearings (240k miles) 1998 E300DT sold to TimFreeh 1987 300TD sold to vstech
|
 |
| Bookmarks |
|
|
Linear Mode
