Not reaching full operating temp
Racer
Joined: Nov 2009
Posts: 489
Likes: 1
From: Suffolk Virginia
I have a simular situation with mine. The gauge always read 160, so I checked and it had a 160 tstat. IK replaced it with a 195, it still reads 160. I guess its a bad tstat, sending unit or guage.
Drifting
Joined: Jun 2010
Posts: 1,781
Likes: 15
From: Oxford Ohio
I agree with the guys suggesting the IR gun. You need to have some "known" information to make better decisions.
I'd guess that some of the parts dealers may have one you could use to check the water temp, upper and lower hose temps and heater hose temps.
I'd guess that some of the parts dealers may have one you could use to check the water temp, upper and lower hose temps and heater hose temps.
Drifting
Joined: Mar 2011
Posts: 1,886
Likes: 9
engine too cold?
Two things could be happening here.
One, enough water could be leaking through the thermostat to keep the engine from ever getting warm enough. The air bleed on it could be too large, or the thermostat might not ever fully close.
The themostat will set the minimum operating temperature and the efficiency of the radiator and water pump will define the upper operating temperature of the engine.
Or, two, the thermostat just opens too soon. See if the upper radiator hose is getting warm right away, immediately after the engine starts. It shouldn't. The thermostat should hold back the water until the operating temp is reached. You can use an infrared thermomoeter if you don't trust your fingers near the fan.
Most likely you will have to pull the 'stat and bring it into the kitchen (when your wife is out!), put it in a pot of water, and turn on the stove. The 'stat should begin to open within maybe 5 F degrees of the marked temperature and be fully open perhaps 15 F degrees higher than that.
I personally believe a 160 is too cold, by the by. If the factory thought that was a good idea, they would have done that from the start.
One, enough water could be leaking through the thermostat to keep the engine from ever getting warm enough. The air bleed on it could be too large, or the thermostat might not ever fully close.
The themostat will set the minimum operating temperature and the efficiency of the radiator and water pump will define the upper operating temperature of the engine.
Or, two, the thermostat just opens too soon. See if the upper radiator hose is getting warm right away, immediately after the engine starts. It shouldn't. The thermostat should hold back the water until the operating temp is reached. You can use an infrared thermomoeter if you don't trust your fingers near the fan.
Most likely you will have to pull the 'stat and bring it into the kitchen (when your wife is out!), put it in a pot of water, and turn on the stove. The 'stat should begin to open within maybe 5 F degrees of the marked temperature and be fully open perhaps 15 F degrees higher than that.
I personally believe a 160 is too cold, by the by. If the factory thought that was a good idea, they would have done that from the start.
Le Mans Master
Joined: Oct 2007
Posts: 7,453
Likes: 976
From: RI, Now Franklin/Nashville TN
I have the same issue with my 78 L-82. Changed to a Dewitts aluminum radiator and aluminum Stewart Stage 2 water pump that requires a modified Robertshaw thermostat since their water pumps do not have an air pocket release mechansim so the thermostat has 3 drilled holes in it to allow water to always go partially around the thermostat. I am using a 180 thermostat which is fine during the late spring, summer, and early fall but I too cannot get the temperature to even 160 when it is cool, not cold. When cold, almost impossible to get the temp to 145-150. My problem is the holes in the thermostat so I am planning on buying another 180 thermostat and drilling just 1 hole for the air pocket issue. Those Dewitts radiators really extract heat in my case. Hope that helps.
Racer
Joined: Dec 2009
Posts: 380
Likes: 0
From: Glendale AZ
I had this problem as well using the Stant and "High Flow" from Mr Gasket thermostats.
I used the 195 Stant thermostat and my car took forever to reach full temp.
I switched to a Delco unit , now the car gets to 195 in no time even with both electric fans on (haven't hooked up a switch yet). I am much more satisfied with the Delco thermostat actually keeping the car around 200 degrees as opposed to the Stant unit which would vary from 160 to 200 depending on how much air was flowing.
In short, aftermarket stats seem to be poorly calibrated garbage in my experience.
I used the 195 Stant thermostat and my car took forever to reach full temp.
I switched to a Delco unit , now the car gets to 195 in no time even with both electric fans on (haven't hooked up a switch yet). I am much more satisfied with the Delco thermostat actually keeping the car around 200 degrees as opposed to the Stant unit which would vary from 160 to 200 depending on how much air was flowing.
In short, aftermarket stats seem to be poorly calibrated garbage in my experience.
Last edited by volition; Mar 5, 2011 at 12:11 AM.
Le Mans Master
Joined: Oct 2007
Posts: 7,453
Likes: 976
From: RI, Now Franklin/Nashville TN
I had this problem as well using the Stant and "High Flow" from Mr Gasket thermostats.
I used the 195 Stant thermostat and my car took forever to reach full temp.
I switched to a Delco unit , now the car gets to 195 in no time even with both electric fans on (haven't hooked up a switch yet). I am much more satisfied with the Delco thermostat actually keeping the car around 200 degrees as opposed to the Stant unit which would vary from 160 to 200 depending on how much air was flowing.
In short, aftermarket stats seem to be poorly calibrated garbage in my experience.
I used the 195 Stant thermostat and my car took forever to reach full temp.
I switched to a Delco unit , now the car gets to 195 in no time even with both electric fans on (haven't hooked up a switch yet). I am much more satisfied with the Delco thermostat actually keeping the car around 200 degrees as opposed to the Stant unit which would vary from 160 to 200 depending on how much air was flowing.
In short, aftermarket stats seem to be poorly calibrated garbage in my experience.
Race Director
Joined: Mar 2006
Posts: 14,112
Likes: 28
From: Florida
I may try a Delco thermostat but have been using the Robertshaw thermostats for 30 years and they have always been reliable although I did replace my old Robertshaw thermostat 2 years ago with the new "modified" one when I put in the Dewitts Radiator and the Stewart water pump. May be worth a try. Thanx.
I used a stage 2 with a 4 core brass rad and that was more than enough.
A simple test and or temporary cold weather cure is to just block of some of the radiator like the big over the road trucks.
Most use shuttered grills, but years ago, the would snap a vinyl cover over all or part of the grill.
I remember seeing them with only about 10% of the grille open in very cold weather.
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Le Mans Master
Joined: Oct 2007
Posts: 7,453
Likes: 976
From: RI, Now Franklin/Nashville TN
I doubt you need both the alum rad and the stage 2 (because of the blocked internal bypass).
I used a stage 2 with a 4 core brass rad and that was more than enough.
A simple test and or temporary cold weather cure is to just block of some of the radiator like the big over the road trucks.
Most use shuttered grills, but years ago, the would snap a vinyl cover over all or part of the grill.
I remember seeing them with only about 10% of the grille open in very cold weather.
I used a stage 2 with a 4 core brass rad and that was more than enough.
A simple test and or temporary cold weather cure is to just block of some of the radiator like the big over the road trucks.
Most use shuttered grills, but years ago, the would snap a vinyl cover over all or part of the grill.
I remember seeing them with only about 10% of the grille open in very cold weather.
