SL/R129: What happens if I remove my thermostat?
12-19-2003, 02:01 AM
#2
MBWorld Fanatic!
which thermostat are you referring to?
the one that measures your engine temp? outside air temp? or the one that measure cabin temp?
for my CLK430, I can unplug the outside temperature probe... all that will do will yield a display that shows "-36 F" or something like that... it doesn't really effect anything, but just won't give you a reading for the outside temp...
the one that measures your engine temp? outside air temp? or the one that measure cabin temp?
for my CLK430, I can unplug the outside temperature probe... all that will do will yield a display that shows "-36 F" or something like that... it doesn't really effect anything, but just won't give you a reading for the outside temp...
12-19-2003, 02:35 PM
#3
Almost a Member!
Join Date: Jul 2003
Location: Chicago
Posts: 49
Likes: 0
Received 0 Likes
on
0 Posts
1997 SL500
amgmercedes- I cannot tell you if this is the case with the mercedes but I can give you a reason why not to disconnect the thrermostat based on my past engine work(mustang and Jeeps). The thermostats job is to keep liquid in the radiator long enough to cool it. The manufactures have set a certin temp that the engine can run at before it needs to be cooled. If the operating temp of the engine is below the thermostate temp level (say 180 degrees), there is no reason to try to cool the engine down lower than that temp.
When the thermostat is close the coolant in the radiator will continue to cool. Even if the outside temp is 100 degrees it will still be cooler than what your engine temp is. When the temp outside is in the higher levels it will take more time for the coolant to cool while in the radiator. By removing your thermostat, you create a situation where the coolant never sits in the radiator long enough to reduce the temprature of the coolant. Essentially the coolant is constantly circulating and never cools down. You will most likely see a rise in the operating temp.
I have replaced thermostats to a lower temp(180 to 160) which will help the cooling of the engine but you have to make sure you do not lower it to the point where the thermostate is almost always opening. For my mustang, I installed thermostats that ranged from 180 - 140 and found out that the 160 keep the engine the coolest. The 180 was too high of the temp which hindered the cooling of the engine where the 140 was too low and was not giving the coolant sufficant enough time to cool.
This is just my knowledge on thermostats and NOT knowledge on mercedes but I have a feeling that the thermodynamic priciples are the same. I hope this sheds some light on the situation
When the thermostat is close the coolant in the radiator will continue to cool. Even if the outside temp is 100 degrees it will still be cooler than what your engine temp is. When the temp outside is in the higher levels it will take more time for the coolant to cool while in the radiator. By removing your thermostat, you create a situation where the coolant never sits in the radiator long enough to reduce the temprature of the coolant. Essentially the coolant is constantly circulating and never cools down. You will most likely see a rise in the operating temp.
I have replaced thermostats to a lower temp(180 to 160) which will help the cooling of the engine but you have to make sure you do not lower it to the point where the thermostate is almost always opening. For my mustang, I installed thermostats that ranged from 180 - 140 and found out that the 160 keep the engine the coolest. The 180 was too high of the temp which hindered the cooling of the engine where the 140 was too low and was not giving the coolant sufficant enough time to cool.
This is just my knowledge on thermostats and NOT knowledge on mercedes but I have a feeling that the thermodynamic priciples are the same. I hope this sheds some light on the situation
12-19-2003, 08:34 PM
#4
MBWorld Fanatic!
amgmercedes - If you are talking about the cooling system "radiator" thermostat, don't even think about removing it. Contrary to popular myth, the thermostat sets the minimum temperature that the engine operates at, not the maximum. The maximum operating temperature is a function of engine ouput (load) and how well designed and maintined the cooling system is. On almost all modern cars, the cooling system has plenty of "overhead" to manage heat disipation under even the worst conditions. This is a direct result of the heat/cold driving cycle testing requirments for modern emission controlled engines.
If you remove the thermostat, the engine will run at a variable temperature (on a modern car this usually too cold because of the large cooling capacities) that is a function of the weather and driving conditions. This temperature is unlikely to be that which is required for proper operation of the engine management system. The end result of this is likely to be radically reduced fuel economy, greater emissions, and the setting of MIL or "fault" conditions in the ECU. If the system runs rich for a long period of time, it can also cause a pehenomenon known as cylinder oil scrubbing; the rich fuel/air mixture "scrubs" the oil off of the cylinder walls, resulting in premature piston/ring/cylinder wear and engine failure.
If you are having problems with over-temperature, something else is wrong. Fix the problem, not the symptom.
- FD
If you remove the thermostat, the engine will run at a variable temperature (on a modern car this usually too cold because of the large cooling capacities) that is a function of the weather and driving conditions. This temperature is unlikely to be that which is required for proper operation of the engine management system. The end result of this is likely to be radically reduced fuel economy, greater emissions, and the setting of MIL or "fault" conditions in the ECU. If the system runs rich for a long period of time, it can also cause a pehenomenon known as cylinder oil scrubbing; the rich fuel/air mixture "scrubs" the oil off of the cylinder walls, resulting in premature piston/ring/cylinder wear and engine failure.
If you are having problems with over-temperature, something else is wrong. Fix the problem, not the symptom.
- FD
12-19-2003, 11:26 PM
#5
Member
Thread Starter
Join Date: May 2003
Posts: 159
Likes: 0
Received 0 Likes
on
0 Posts
Thanks for the info, I thought removing the thermostat would lower engine operating temps.
I really dont know if I have a problem or not, its just that my 500SL' s normal operating temp is about 90 to 100 degrees. It climbs to about 110 - 115 in really bad traffic (wherein you move only 2km in half an hour). Although the engine has never overheated, Im sure the high temps does it no favors. The 2 aux fans are working fine on highspeed, entire cooling system seems to be in good shape.
Im just comparing it to my 93' E420 which basically has the same engine, its normal operating temp is only about 70 to 75 degrees, and only climbs to a max of about 90 in real bad traffic.
I really dont know if I have a problem or not, its just that my 500SL' s normal operating temp is about 90 to 100 degrees. It climbs to about 110 - 115 in really bad traffic (wherein you move only 2km in half an hour). Although the engine has never overheated, Im sure the high temps does it no favors. The 2 aux fans are working fine on highspeed, entire cooling system seems to be in good shape.
Im just comparing it to my 93' E420 which basically has the same engine, its normal operating temp is only about 70 to 75 degrees, and only climbs to a max of about 90 in real bad traffic.
12-19-2003, 11:28 PM
#6
Member
Thread Starter
Join Date: May 2003
Posts: 159
Likes: 0
Received 0 Likes
on
0 Posts
BTW, im in a tropical country.
And I seem to have mixed opinions from the guys on this board, some say they also see high temps, while others dont. So Im not sure if the temps are seeing are normal or not.
And I seem to have mixed opinions from the guys on this board, some say they also see high temps, while others dont. So Im not sure if the temps are seeing are normal or not.
12-20-2003, 02:29 AM
#7
MBWorld Fanatic!
What good is removing the thermostat going to do you? If it's working correctly, in high ambient temperatures, the thermostat will be allowing maximum flow through the radiator to maximise cooling, assisted by the fans.
Believe me, Mercedes will have done a good job of assessing the high temperature performance of your car. Getting rid of all the heat in a high performance car is one of the design imperatives.
Believe me, Mercedes will have done a good job of assessing the high temperature performance of your car. Getting rid of all the heat in a high performance car is one of the design imperatives.
Trending Topics
12-31-2003, 11:49 AM
#8
Almost a Member!
Join Date: Jul 2003
Location: Chicago
Posts: 49
Likes: 0
Received 0 Likes
on
0 Posts
1997 SL500
If your car is running hotter then you may like there is a product that I used to use in my mustang(350hp) that helped lower the temp. Plus it is has other benefits such as lubrication of moving parts and corrosion control. The product is called Water Wetter and is sold by Redline. I have provided a link to the technical information on the product.
I forgot to add that this was a daily driver and not just a track car.
http://www.redlineoil.com/redlineoil/wwti.htm
I forgot to add that this was a daily driver and not just a track car.
http://www.redlineoil.com/redlineoil/wwti.htm
05-25-2009, 06:45 AM
#9
Newbie
Join Date: May 2009
Posts: 1
Likes: 0
Received 0 Likes
on
0 Posts
lancer
When the thermostat is abutting the coolant in the radiator will abide to cool. Even if the alfresco acting is 100 degrees it will still be acknowledgment than what your engine acting is. When the acting alfresco is in the college levels it will yield added time for the coolant to air-conditioned while in the radiator. By removing your thermostat, you actualize a bearings area the coolant never sits in the radiator continued abundant to abate the temprature of the coolant. Essentially the coolant is consistently circulating and never cools down. You will a lot of acceptable see a acceleration in the operating temp.
If you abolish the thermostat, the engine will run at a capricious temperature (on a avant-garde car this usually too algid because of the ample cooling capacities) that is a action of the acclimate and active conditions. This temperature is absurd to be that which is appropriate for able operation of the engine administration system. The end aftereffect of this is acceptable to be radically bargain ammunition economy, greater emissions, and the ambience of MIL or "fault" altitude in the ECU. If the arrangement runs affluent for a continued aeon of time, it can aswell could cause a pehenomenon accepted as butt oil scrubbing; the affluent fuel/air admixture "scrubs" the oil off of the butt walls, consistent in abortive piston/ring/cylinder abrasion and engine failure.
_________________
Thermostat
If you abolish the thermostat, the engine will run at a capricious temperature (on a avant-garde car this usually too algid because of the ample cooling capacities) that is a action of the acclimate and active conditions. This temperature is absurd to be that which is appropriate for able operation of the engine administration system. The end aftereffect of this is acceptable to be radically bargain ammunition economy, greater emissions, and the ambience of MIL or "fault" altitude in the ECU. If the arrangement runs affluent for a continued aeon of time, it can aswell could cause a pehenomenon accepted as butt oil scrubbing; the affluent fuel/air admixture "scrubs" the oil off of the butt walls, consistent in abortive piston/ring/cylinder abrasion and engine failure.
_________________
Thermostat
05-25-2009, 06:57 AM
#10
MBWorld Fanatic!
When the thermostat is abutting the coolant in the radiator will abide to cool. Even if the alfresco acting is 100 degrees it will still be acknowledgment than what your engine acting is. When the acting alfresco is in the college levels it will yield added time for the coolant to air-conditioned while in the radiator. By removing your thermostat, you actualize a bearings area the coolant never sits in the radiator continued abundant to abate the temprature of the coolant. Essentially the coolant is consistently circulating and never cools down. You will a lot of acceptable see a acceleration in the operating temp.
If you abolish the thermostat, the engine will run at a capricious temperature (on a avant-garde car this usually too algid because of the ample cooling capacities) that is a action of the acclimate and active conditions. This temperature is absurd to be that which is appropriate for able operation of the engine administration system. The end aftereffect of this is acceptable to be radically bargain ammunition economy, greater emissions, and the ambience of MIL or "fault" altitude in the ECU. If the arrangement runs affluent for a continued aeon of time, it can aswell could cause a pehenomenon accepted as butt oil scrubbing; the affluent fuel/air admixture "scrubs" the oil off of the butt walls, consistent in abortive piston/ring/cylinder abrasion and engine failure.
If you abolish the thermostat, the engine will run at a capricious temperature (on a avant-garde car this usually too algid because of the ample cooling capacities) that is a action of the acclimate and active conditions. This temperature is absurd to be that which is appropriate for able operation of the engine administration system. The end aftereffect of this is acceptable to be radically bargain ammunition economy, greater emissions, and the ambience of MIL or "fault" altitude in the ECU. If the arrangement runs affluent for a continued aeon of time, it can aswell could cause a pehenomenon accepted as butt oil scrubbing; the affluent fuel/air admixture "scrubs" the oil off of the butt walls, consistent in abortive piston/ring/cylinder abrasion and engine failure.
05-25-2009, 01:10 PM
#11
Banned
Pretty amusing to read. I suppose that was some program translating the poster's native language to English.
I would put the climate controller in diagnostic mode and compare its coolant temperature reading to that of the cluster as explained here: http://www.peachparts.com/shopforum/...ad.php?t=86546. On an older car there are separate sensors, and it is possible that the one for the cluster is reading too high and your engine is running cooler than you think.
I would put the climate controller in diagnostic mode and compare its coolant temperature reading to that of the cluster as explained here: http://www.peachparts.com/shopforum/...ad.php?t=86546. On an older car there are separate sensors, and it is possible that the one for the cluster is reading too high and your engine is running cooler than you think.
05-25-2009, 01:47 PM
#12
Junior Member
Join Date: Jan 2003
Location: Bay Area
Posts: 74
Likes: 0
Received 0 Likes
on
0 Posts
1987 190E 2.3-16V
If you remove the thermostat, there are various sensors in the engine that require the temp to be where they are when the thermostat is in place. Also if you remove the thermostat, you will make the water circulate in the engine unimpeded, and may not allow enough time for the radiator to cool the water.
If you are experiencing high temps, change the thermostat, as it may not be opening all the way or may be stuck in a partially open position causing the high temps.
