Engine overheating or Busted temp. guage?
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Joined: Dec 2015
Posts: 79
From: Cornelius - North Carolina
Engine overheating or Busted temp. guage?
Hello - I have a 70 Cutlass Supreme with a 355 engine and I installed a Bosch temperature guage.
When driving for 30-45 minutes at speed of 35-55 the guage would shows the engine would quickly overheate at times getting the temperature up to 230-250 degrees so I took it to my mechanic and we found the radiator has a small leak and the fan blade was not working so we replaced the fan blade and fixed the radiator however even tough it helped a bit the temperature continued to rise so I replaced the thermostat to 160 and the radiator cap which was not holding on the pressure but the temperature continues to rise hitting 210 after 15-30 minutes of driving so I bought it back to the mechanic and he drove the car for a while and tested the engine temperature and told me that based on his test the temperature was ok that the issue may be with a busted temperature guage, could this be?
I live in North Carolina so it's hot here in the summer but that does not explain why the temperature gets so high.
I looked at some old threads that discussed overheating and most mentioned following the same steps, replace thermostat, check engine fan blade, radiator but after these steps I am lost. Before replacing the guage has any of you come across a busted guage before or am I looking at a bigger issue?
I drove the car yesterday for about 30 minutes and the temp stayed at 190 for about 15 minutes then jumped to 210. And I can feel the heat inside the cabin and I don't use the AC b/c the temperature will really take off.
Thanks for your help in advance.
When driving for 30-45 minutes at speed of 35-55 the guage would shows the engine would quickly overheate at times getting the temperature up to 230-250 degrees so I took it to my mechanic and we found the radiator has a small leak and the fan blade was not working so we replaced the fan blade and fixed the radiator however even tough it helped a bit the temperature continued to rise so I replaced the thermostat to 160 and the radiator cap which was not holding on the pressure but the temperature continues to rise hitting 210 after 15-30 minutes of driving so I bought it back to the mechanic and he drove the car for a while and tested the engine temperature and told me that based on his test the temperature was ok that the issue may be with a busted temperature guage, could this be?
I live in North Carolina so it's hot here in the summer but that does not explain why the temperature gets so high.
I looked at some old threads that discussed overheating and most mentioned following the same steps, replace thermostat, check engine fan blade, radiator but after these steps I am lost. Before replacing the guage has any of you come across a busted guage before or am I looking at a bigger issue?
I drove the car yesterday for about 30 minutes and the temp stayed at 190 for about 15 minutes then jumped to 210. And I can feel the heat inside the cabin and I don't use the AC b/c the temperature will really take off.
Thanks for your help in advance.
Administrator
Joined: Oct 2009
Posts: 42,475
From: Poteau, Ok
By your description, your initial problem was due to the leaky radiator. The level would drop causing an air pocket which cause erratic gauge movements. Thermostats only control the minimum operating temp of the engine so going to a 160* really accomplishes nothing except increase the time it takes to get to the max temp. Check your timing, declined timing will make an engine run hotter. BTW 210 is nowhere near overheating.
Does your radiator have a shroud, is there a clutch fan installed, is the fan centered in the shroud opening?
Does your radiator have a shroud, is there a clutch fan installed, is the fan centered in the shroud opening?
Hookers under Hood
Joined: Nov 2013
Posts: 3,543
From: Ontario, Canada
I agree with Oldcutlass, follow up with his checklist of recommendations and post your findings here . 195-210 after 30 min is normal as Eric mentioned, normal highway/city driving. I would put a 180 t-stat back in if it were me after you complete the above checklist.
Out of Line, Everytime😉
Joined: Dec 2006
Posts: 10,087
From: Melville, Saskatchewan
While 210 isn't overheating, I personally don't like it, especially if the motor is getting tired. Add a shroud, sounds like the fan clutch was replaced and consider getting a 2 core aluminum with 1" or larger tubes radiator. As said, buy the infared temp gun and check for the actual temp.
Last edited by olds 307 and 403; Aug 20, 2018 at 08:16 PM.
Thread Starter
Registered User
Joined: Dec 2015
Posts: 79
From: Cornelius - North Carolina
Thank you all!!!
To answer some questions from above.
Does your radiator have a shroud, is there a clutch fan installed, is the fan centered in the shroud opening? Yes, I do have a shroud and it is pretty I centered.
I will get the infrared gun to test it out.
How do I test the timing? Is there a youtube video for something like this?
And if 210 degrees is Ok, what should be the threshold 220-230 before I start to get concerned?
Thanks in advance,
To answer some questions from above.
Does your radiator have a shroud, is there a clutch fan installed, is the fan centered in the shroud opening? Yes, I do have a shroud and it is pretty I centered.
I will get the infrared gun to test it out.
How do I test the timing? Is there a youtube video for something like this?
And if 210 degrees is Ok, what should be the threshold 220-230 before I start to get concerned?
Thanks in advance,
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