Parts Catalog Accessories Catalog How To Articles Tech Forums
Call Pelican Parts at 888-280-7799
Shopping Cart Cart | Project List | Order Status | Help



Go Back   PeachParts Mercedes-Benz Forum > Mercedes-Benz Tech Information and Support > Diesel Discussion

Reply
 
LinkBack Thread Tools Display Modes
  #1  
Old 08-01-2005, 03:07 PM
Registered User
 
Join Date: May 2005
Posts: 2
Exclamation 300D overheating

My 1992 300D has run hot since I moved to Arizona. I've replaced the radiator, thermostat, cleaned the A/C condensor and have a 50/50 mix with wetter water. When I run uphill on I-17 at 75 mph the temperture goes straignt to 115-120C. Turning off the air conditioner keeps the temp from going to 120. Is this normal? I've been reading on this site about "citric flush" which my local mechanic has never recommended. Any ideas??

Reply With Quote
  #2  
Old 08-01-2005, 03:26 PM
BusyBenz
Guest
 
Posts: n/a
What about your electric auxiliary fan, or belt driven fan clutch?

The aux fan should come on at or around 105c, if not, check the temp sensor, they do go bad!
Reply With Quote
  #3  
Old 08-01-2005, 07:01 PM
Registered User
 
Join Date: Nov 2004
Location: Exit 191, I-25
Posts: 124
one idea.... you could sell it to me cheap. then, i'll let you know how it runs in nuevo mexico. LOL.
another idea, have you blown the radiator and condenser out with air? get all the bugs and and dirt out you can. don't use water, it will just make mud.
check your thermostat to see if it's opening all it should.

where is the temp sensor for the electric fan located???
__________________
Current money-pits:
96 Passat TDI
78 300D 100k miles(60miles/day)FOR SALE
91 Jetta Diesel 250k miles (80miles/day)
82 Toyota Diesel pickup 150k miles; out of service for a little while with a valve problem.
All on BelenBioDiesel
Past diesels:
01 Golf TDI
81 Isuzu P/U
85 Jetta
89 KW 425 cat
85 Pete 400 cat (currently still running the west coast with over 1.5 million miles)
81 KW 400 Cummins
77 Freightliner CO ???? Cummins (Buttercup)
57 180D lots of miles(gone but not forgotten)
Reply With Quote
  #4  
Old 08-01-2005, 07:09 PM
BusyBenz
Guest
 
Posts: n/a
Quote:
Originally Posted by boxscar

where is the temp sensor for the electric fan located???
The aux fan temp sensor is located forward top of engine, very near to the upper radiator hose. Should be 2 sensors there, one with 2 pins, the other with 3 pins. I believe the one were talking about is the 2 pin.
Reply With Quote
  #5  
Old 08-01-2005, 07:29 PM
whunter's Avatar
Moderator
 
Join Date: Dec 2003
Location: Metro Detroit, Michigan
Posts: 17,416
Ideas

Quote:
Originally Posted by Paul Feirick
My 1992 300D has run hot since I moved to Arizona. I've replaced the radiator, thermostat, cleaned the A/C condensor and have a 50/50 mix with wetter water. When I run uphill on I-17 at 75 mph the temperture goes straignt to 115-120C. Turning off the air conditioner keeps the temp from going to 120. Is this normal? I've been reading on this site about "citric flush" which my local mechanic has never recommended. Any ideas??
Here are some possible causes for your problem.

Aux. Fan Resistor
Auxiliary Fan Assembly
Engine Temp. Sensor
Fan Clutch...
Water Pump
A/C ACC Temp Sensor
A/C Temp. Switch
__________________
ASE Master Mechanic
asemastermechanic@juno.com

Prototype R&D/testing:
Thermal & Aerodynamic System Engineering (TASE) Senior vehicle instrumentation technician.
Noise Vibration and Harshness (NVH).
Dynamometer.
Heat exchanger durability.
HV-A/C Climate Control.
Vehicle build.
Fleet Durability
Technical Quality Auditor.
Automotive Technical Writer

1985 300SD
1983 300D
1984 190D
2003 Volvo V70
2002 Honda Civic

https://www.boldegoist.com/
Reply With Quote
  #6  
Old 08-02-2005, 07:51 AM
Geezer
 
Join Date: Aug 2000
Location: Holland, MI
Posts: 1,316
Quote:
Originally Posted by Paul Feirick
...uphill on I-17 at 75 mph the temperature goes straignt to 115-120C.
This requires a high percentage of the total engine horsepower, which will put a significant percentage of total heat into the radiator.

75mph produces a lot of 'ram air' effect, so I don't think the auxiliary fan adds much to the airflow. Ditto the engine-driven fan. The cooling is determined by the radiator effective area and the water pump flow rate.

Quote:
My 1992 300D has run hot since I moved to Arizona...
Ambient temperature has an effect, too!

It sounds like it is not overheating, it is just running at the hot end of allowable. Given high ambient temperature and high horsepower requirements, it is to be expected.

By the way, what does the temperature gauge read when you are going downhill? It should drop back to 80-85C...

Best Regards,
Jim
Reply With Quote
  #7  
Old 08-02-2005, 10:30 AM
Registered User
 
Join Date: May 2005
Posts: 2
300D overheating

Thanks for the help. The temp drops bak to 80C when the car goes downhill. Temperature is a factor, but the car will get hot going up hill in cool weather without the A/C. My local mechanic--very good--says this high temperature is normal. I'm wondering if I need to flush. Everything else has been replaced or checked.
Reply With Quote
  #8  
Old 08-02-2005, 12:46 PM
Geezer
 
Join Date: Aug 2000
Location: Holland, MI
Posts: 1,316
Quote:
Originally Posted by Paul Feirick
...The temp drops back to 80C when the car goes downhill. Temperature is a factor, but the car will get hot going up hill in cool weather without the A/C. My local mechanic--very good--says this high temperature is normal. I'm wondering if I need to flush. Everything else has been replaced or checked.
It sounds normal, especially since you have replaced the 'usual suspects' of thermostat and radiator.

I think you can trust your mechanic. Watch it for a while. A flush won't hurt, but it may not help, either...

Best Regards,
Jim
Reply With Quote
  #9  
Old 10-19-2005, 07:40 AM
Registered User
 
Join Date: Oct 2005
Posts: 9
Does Auxiliary Water Pump useful for reducing overheat?
Can I replace the expansion plastic tank with a bigger one on my 300E86? What is compatible?
Reply With Quote
  #10  
Old 10-19-2005, 09:53 AM
t walgamuth's Avatar
dieselarchitect
 
Join Date: Apr 2005
Location: Lafayette Indiana
Posts: 38,610
only thing

left is the water pump. i would prob change that. be sure to get the origninl style with the cast impeller blades.

tom w

__________________
[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.
Reply With Quote
Reply

Bookmarks

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 On
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Opinions on purchasing a 1987 300D swogee Diesel Discussion 12 05-03-2005 10:27 AM
1976 W115 300D motor into 1979 W123 300D sebtowne114 Diesel Discussion 5 04-14-2005 07:26 AM
Mercedes Parts FS!! 300e & 300d Cruise Control, 450sl fuel distributer, 300d cluster 6cndmbz Mercedes-Benz Used Parts For Sale & Wanted 0 04-18-2004 02:31 PM
Parts Interchange 81 300D into 83 300D BigMikeT57 Diesel Discussion 2 04-13-2004 01:38 AM
1985 300D Turbo Overheating. rlboulle Tech Help 6 08-31-1999 04:29 PM



All times are GMT -4. The time now is 10:27 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2024, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2024 Pelican Parts, LLC - Posts may be archived for display on the Peach Parts or Pelican Parts Website -    DMCA Registered Agent Contact Page