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 > Vintage Mercedes Forum

Reply
 
LinkBack Thread Tools Display Modes
  #1  
Old 04-05-2006, 06:13 PM
Registered User
 
Join Date: Dec 2005
Posts: 2,423
Can you go without themostat during summer?

Replacing thermostat and wonder if I can just do without it completely?

Reply With Quote
  #2  
Old 04-05-2006, 06:53 PM
250 Coupe's Avatar
Middle Aged Member
 
Join Date: Mar 2004
Location: Des Moines, WA
Posts: 927
I wouldn't.

Car needs to run at design temperatures for a number of reasons.

Emissions.

Fuel economy.

Drivability.

Longevity.

Michael
__________________
Usta haves '69 250/8, '76 280C, 1971 250C 114.023, 1976 450SEL 116.033
Current have, 1983 300SD 126.120
Reply With Quote
  #3  
Old 04-05-2006, 08:14 PM
Super Moderator
 
Join Date: Apr 2000
Location: Falls Church, VA
Posts: 5,318
You don't say what car you have. But there is possibly another reason why not having a thermostat is not a good idea. On the V8's and maybe some of the sixes, the thermostat controls whether coolant goes to the bypass, meaining directly back to the engine to make warmup faster, or to the radiator for cooling. At operating temps, the thermostat actually closes the bypass. So if you pull the thermostat out, you may be sending too much coolant to the bypass route and actually impeding cooling.

I was kind of surprised to learn this from reading the V8 CD section on the cooling system.
__________________
Chuck Taylor
Falls Church VA
'66 200, '66 230SL, '96 SL500. Sold: '81 380SL, '86 300E, '72 250C, '95 C220, 3 '84 280SL's '90 420SEL, '72 280SE, '73 280C, '78 280SE, '70 280SL, '77 450SL, '85 380SL, '87 560SL, '85 380SL, '72 350SL, '96 S500 Coupe
Reply With Quote
  #4  
Old 04-05-2006, 08:54 PM
Tomguy's Avatar
Vintage Moderator
 
Join Date: Aug 2002
Location: near Scranton, PA
Posts: 5,407
The worst thing that could happen is your engine will overheat and you'll blow a head gasket or crack the block.

The least that would happen is a LOT lower fuel efficiency, as your engine never reaches proper operating temperature. This could also cause gunk to build up in the oil or exhaust that normally would boil or burn out at normal operating temperatures.

It's NOT a good idea. A thermostat cant be over $30 and I wouldnt risk runing my engine over a $30 part.
__________________
Current:
2021 Charger Scat Pack Widebody "Sinabee"
2018 Durango R/T

Previous:
1972 280SE 4.5
2014 Jeep Grand Cherokee Limited "Hefe", 1992 Jeep Cherokee Laredo "Jeepy", 2006 Charger R/T "Hemi"
1999 Chrysler 300M - RIP @ 221k
Reply With Quote
  #5  
Old 04-05-2006, 11:28 PM
t walgamuth's Avatar
dieselarchitect
 
Join Date: Apr 2005
Location: Lafayette Indiana
Posts: 38,613
i agree totally

dont run wo the stat.

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
  #6  
Old 04-06-2006, 01:32 AM
mzsmbs's Avatar
just out there!
 
Join Date: Aug 2003
Location: just out there!
Posts: 2,192
i run without a t-stat on my s-10 year round with no problems. it was an attempt to keep it cooler because it tends to vapor lock. seems to help. i ran my f-150 like that for years, no problems either. most of heavy construction equimpment runs without t-stats and those things practically run non stop all day. i wouldn't worry about it. as someone said, you may overheat your engine but if you run just water (w/ a little waterwetter or small amount of coolant) you should be just fine. water looses heat soooo much better/faster then coolant.
__________________
72 W114/M130

RedMeat cartoon
Reply With Quote
  #7  
Old 04-06-2006, 06:18 AM
300SDog's Avatar
gimme a low-tech 240D
 
Join Date: Jan 2003
Location: central ky
Posts: 3,602
I've run without T-stat for couple of Summers as last ditch measure to improve MB cooling. And with no thermostat the operating temp will drop 5-10 degrees. But its more of a July/August or severe heat wave kinda thing to do. With no thermostat at all the car will take helluva lot longer to reach operating temp.
Reply With Quote
  #8  
Old 04-06-2006, 08:49 AM
t walgamuth's Avatar
dieselarchitect
 
Join Date: Apr 2005
Location: Lafayette Indiana
Posts: 38,613
msbz

those cars you mention do not have by pass thermostats.

in a non bypass thermostat the only danger is running too cool which is not good but not too dangerous.

in a benz it will cause it to run hot in the warm weather. this is potentially very damaging and costly.

if you dont understand it read ali's post again or look in your repair manual. most of them offer diagrams describing the path of the coolant in a benz BYPASS thermostatic cooling system.

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
  #9  
Old 04-06-2006, 08:08 PM
300SDog's Avatar
gimme a low-tech 240D
 
Join Date: Jan 2003
Location: central ky
Posts: 3,602
Tom, I've heard that argument before replete with "proof" (hydro/thermal engineering theory based on water flow) backed up with shop manual schematics that show how many MB engines, even my bypass system 240D, will run hotter w/out thermostat. But in reality thats not entirely true, at least it doesnt apply to what I've seen from my own experience.

Without hesitation you can go ahead and pull the thermostat and toss it in the trunk during hot Summer months, then see for yourself how the engine performs. And if it does NOT run better and cooler, just pull over and reinstall it...... no big deal.

I dunno what all the scarey caution is about. Anybody who keeps an eye on engine temp will never blow a head gasket. Thats a girlie problem, not paying attention to engine guages, kinda like running the car out of oil.

Last edited by 300SDog; 04-06-2006 at 08:25 PM.
Reply With Quote
  #10  
Old 04-06-2006, 08:21 PM
t walgamuth's Avatar
dieselarchitect
 
Join Date: Apr 2005
Location: Lafayette Indiana
Posts: 38,613
why do i want

to go around watching my guage all the time? just to prove i can run without a stat? and i dont care if you call me girlie. i have five kids. i dont have to prove my manhood.

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
  #11  
Old 04-06-2006, 08:44 PM
300SDog's Avatar
gimme a low-tech 240D
 
Join Date: Jan 2003
Location: central ky
Posts: 3,602
>>>why do i want to go around watching my guage all the time? just to prove i can run without a stat?

because its probly a good idea for everybody during summer months, 2nd nature for many.... and pulling the T-stat should make it run cooler, lowered temp 5-10 degrees for me

>>> and i dont care if you call me girlie. i have five kids. i dont have to prove my manhood.

That wasnt directed at you personally. And i apologize if you took it that way. Nobody is challenging you or asking you to proove anything. Running straight H2O instead of coolant with no thermostat is one of the oldest tricks in the book for beating Summertime temps. I'm not saying it works for all MB's, just that its worked for me. Deffinitely worth trying and nothing to get upset about.

Last edited by 300SDog; 04-06-2006 at 08:56 PM.
Reply With Quote
  #12  
Old 04-06-2006, 11:32 PM
t walgamuth's Avatar
dieselarchitect
 
Join Date: Apr 2005
Location: Lafayette Indiana
Posts: 38,613
thanks diesel dog but i wasnt actually offended. it was meant lightheartedly.

if you run cooler without a stat even under a load like running at high speeds or pulling a hill i would be very surprised. can't imagine it. sure you will if you are just diddling around town cause the cooling system never has to get rid o a big load of heat. but the reality is that you are running about half of your maximum design cooling load capacity.

the engine is designed for the oil to be at 175 to 180 degrees faranheit. running cooler will not be good for the motor in the long run. that is why the mbs have an oil cooler to keep the oil in the design temp. same reason they have a stat, to keep it in the design temp.

and it is generally recommended that running 5050 mix of antifreeze will run cooler than straight h2o.

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
  #13  
Old 04-07-2006, 12:14 AM
mzsmbs's Avatar
just out there!
 
Join Date: Aug 2003
Location: just out there!
Posts: 2,192
the design could be so but i know for fact that my MB ran cooler with H20 then it did with the coolant.
__________________
72 W114/M130

RedMeat cartoon
Reply With Quote
  #14  
Old 04-07-2006, 08:51 AM
t walgamuth's Avatar
dieselarchitect
 
Join Date: Apr 2005
Location: Lafayette Indiana
Posts: 38,613
you can do whatever you want, but i will follow the benz factory recommendation.

i dont need to try to remember to add antifreeze when the weather turns cold either.

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
  #15  
Old 04-07-2006, 02:37 PM
Tomguy's Avatar
Vintage Moderator
 
Join Date: Aug 2002
Location: near Scranton, PA
Posts: 5,407
None of you have ever done this on the V8s though, I assume.

My V8 gets so hot sometimes that touching the valve cover will burn my hand. If running without a thermostat causes just 10% of the coolant to recirculate through the block, I'd overheat in 5 mins of idling. Shutting my engine off and restarting it in traffic (or running with the heater on in the summer) is not my idea of fun.

Plus, running coolant at 50/50 affords me an extra 30° or so before boilover. It might run 5-10° hotter, but I can afford those 5-10° because I have a hell of a lot more room before my coolant boils out and my heads become as warped as particle board in a thunderstorm.

__________________
Current:
2021 Charger Scat Pack Widebody "Sinabee"
2018 Durango R/T

Previous:
1972 280SE 4.5
2014 Jeep Grand Cherokee Limited "Hefe", 1992 Jeep Cherokee Laredo "Jeepy", 2006 Charger R/T "Hemi"
1999 Chrysler 300M - RIP @ 221k
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




All times are GMT -4. The time now is 10:34 PM.


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