Parts Catalog Accessories Catalog Tech Info Tech Forums
  Search our site:    
 Cart  | Project List | Order Status | Help    

Go Back   PeachParts Mercedes ShopForum > Technical Information and Support > Tech Help

LinkBack Thread Tools Display Modes
Old 05-13-2002, 02:25 PM
Registered User
Join Date: Mar 2001
Posts: 223
Temperature gauge swings wildly

I have a 190e 2.3 1988
the temperature gauge acts normal, then bounces up and down rapidly (within a second or two) then back to normal. Nowadays it bounces either up or down and stays there, like past the redline as far as it can go.
Any ideas really appreciated, this is my baby here please help.
1996 E320
2000 C230 Kompressor
1988 190e 2.3 - 225K miles, owned for 7 years. I cannot say enough good things about this car. Very well built, even at 225 it ran like new.
Reply With Quote
Old 05-13-2002, 03:04 PM
Posts: n/a
Lightbulb sensor trouble

I drive a 94 200E, so this info might not be 100%, but worth a look anyway ....

The 110deg sensor on my car went bad. I opened the faulty unit to ascertain what could cause the trouble (destroyed it in the process - but it was shot anyway)

It's a mechanical device for switching the aux fan on at 110 whilst it also houses the resistive element for the temp sensor (a three-pronged sensor with 110 stamped on the side).

What happened was that the switching element broke off inside and fell in such a way as to periodically shorting with the temp probe, whilst sometimes causing a short that popped F7 (the aux fan fuse) !! When shorting to the temp probe I got 120deg + on the display whilst it was OK otherwise ...

changed switch / sensor - all fixed. I pulled the sensor as a last resort when testing for bad wiring to the temp sensor proved nothing. A dead short (i.e. chassis earth on the sensor wire) shows 120deg + whilst no contact shows a cold engine - on the 102 engine anyway.

maybe this helps ...

Reply With Quote
Old 05-13-2002, 03:05 PM
Registered User
Join Date: Jun 2000
Location: Saugus, CA USA
Posts: 1,974
Does it jump up like it could be a broken wire? How old is your thermostat? I think they should be part of the scheduled maintance. If it is the real engine temp the thermal shock is bad on the radiator and head gasket. I've seen a varity of failures of thermostats and this could be one of them.
Reply With Quote
Old 05-13-2002, 10:11 PM
Join Date: Jul 2001
Location: Old Lyme, Connecticut
Posts: 3,596

za_w124_200e is likely correct. A flickering guage needle is highly unlikely to be an actual temperature change. For the most part, a quick, less than a second duration transient of 10 or so degrees would not even show up, much less cause the needle to flicker. The response time of the boss, sensor housing and sensor to temperature changes is much longer than a flickering of the needle you described.

I would start with the sensor by checking its response as the engine warms up. Disconnect it and see what the guage does, then record the signal as the engine warms up by checking resistance, and see if it suddenly goes to zero or infinity. If so the problem is in the sensor. If not, it may be in the wiring or the guage in the dash.

Hope this helps. Jim
1986 Euro 190E 2.3-16 (291,000 miles),
1998 E300D TurboDiesel, 231,000 miles -purchased with 45,000,
1988 300E 5-speed 252,000 miles,
1983 240D 4-speed, purchased w/136,000, now with 222,000 miles.
2009 ML320CDI Bluetec, 89,000 miles

1971 220D (250,000 miles plus, sold to father-in-law),
1975 240D (245,000 miles - died of body rot),
1991 350SD (176,560 miles, weakest Benz I have owned),
1999 C230 Sport (45,400 miles),
1982 240D (321,000 miles, put to sleep)
Reply With Quote
Old 05-17-2002, 02:32 AM
Registered User
Join Date: Mar 2001
Posts: 223
finally found the problem

I finally discovered the problem tonight (after replaceing 3 temp senders/switches, the battery and the overvoltage protection relay)
As I was driving I noticed that the temp gauge movement sometimes was in sync with
bumps that I would go over on the road, in other words if the car experienced some movement, the gauge would react at the same time by jerking up and down.
I poped the hood, had my wife watch the temp gauge in the car, I grabbed some wires from the temp sender and pulled them repeatadly, when I did she noticed that the gauge moved when I pulled on the wires. I figured it was a short. I took off the air cleaner, light up the area with a flash light while pulling the wires to expose them, after a bit sure enough I saw a joint with copper wire exposed. I cut off the damaged portion of wiring, spliced it and it works great now. Whew glad my car is back to its old self now. Hope this helps somebody someday.
This is a GREAT GREAT site.
1996 E320
2000 C230 Kompressor
1988 190e 2.3 - 225K miles, owned for 7 years. I cannot say enough good things about this car. Very well built, even at 225 it ran like new.
Reply With Quote


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

All times are GMT -4. The time now is 11:19 AM.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2016, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2011 Pelican Parts - Posts may be archived for display on the Peach Parts or Pelican Parts Website -    DMCA Registered Agent Contact Page