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73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: Slammed83 on January 12, 2011, 02:46:55 pm

Title: Overheating Problem
Post by: Slammed83 on January 12, 2011, 02:46:55 pm
I went out this morning and started my truck up, and it got to about 180 like normal so i took my sister to school. I had the defrost on the whole time and the heat never really kicked in. And then i was about 3 blocks away from her school and it started to overheat really bad and climbed the gauge to about 240. I shut it off and checked the antifreeze, added a little and started it again about 10 minutes ago. The gauge went right back to 240... So can someone tell me what is wrong? im not too bright when it comes to the cooling system..
Title: Re: Overheating Problem
Post by: beastie_3 on January 12, 2011, 02:56:49 pm
When the coolant is cool, open the rad cap and see if there is coolant flow. The pump might have gone out.
Title: Re: Overheating Problem
Post by: screamin86 on January 12, 2011, 03:35:10 pm
Possibly a bad thermostat also!
Title: Re: Overheating Problem
Post by: Slammed83 on January 12, 2011, 03:37:10 pm
Thermostat was my first thought, But there actually isnt any coolant flow because none of the Heating hoses are warm.
Title: Re: Overheating Problem
Post by: Jim Rockford on January 12, 2011, 07:34:01 pm
yup . thermostat is stuck closed , really low on water, or you didn't have enough antifreeze and you radiator was frozen . Never add cold water to a hot engine with it off, and if its over heating do not remove the cap. just hang out and wait for it to cool off and then add water after you get the cap off and then start it up and add coolant.
Title: Re: Overheating Problem
Post by: Slammed83 on January 12, 2011, 08:43:11 pm
It was at 240 before i realized what was happening, So i pulled over and let it cool off.. Then drove it home. I let it cool off for 5 hours while i slept off my cold then went out and it was low on coolant so i added some. It still went up to 240 and i noticed that there is no coolant flow.
Title: Re: Overheating Problem
Post by: Lt.Del on January 12, 2011, 10:30:57 pm
t-stadt
Title: Re: Overheating Problem
Post by: screamin86 on January 13, 2011, 01:36:36 am
Fail safe all the way!
Title: Re: Overheating Problem
Post by: 1980c10 on January 13, 2011, 06:15:10 pm
check the weep hole on your water pump while your checking stuff.
Title: Re: Overheating Problem
Post by: 86k20 on January 13, 2011, 06:35:58 pm
could be a bad water pump and a thermostat
Title: Re: Overheating Problem
Post by: Slammed83 on January 13, 2011, 10:47:06 pm
I changed the Thermostat and water pump today, Somewhat fixed the problem, Im looking into the radiator not getting cooled by the fan efficiently..
Title: Re: Overheating Problem
Post by: 1980c10 on January 14, 2011, 02:39:08 am
It could also be that your radiator is partially plugged. 
If it overheats while driving suspect your radiator.
If it overheats while not driving (at idle) suspect your fan.
If you are still losing coolant you may want to pressure test the cooling system.
Title: Re: Overheating Problem
Post by: Slammed83 on January 14, 2011, 03:33:05 pm
Alright. I think its the fan.. I was drivin this morning and it was at 210.. Sped up to 60 and it dropped to 180
Title: Re: Overheating Problem
Post by: beastie_3 on January 14, 2011, 04:51:26 pm
How long have you owned the truck?

Did you remove the fan shroud?

I have never had a shroud on mine as long as ive owned it and my flex fan is about 4 inches away from the radiator. Ive never had a problem with it overheating.
Title: Re: Overheating Problem
Post by: Slammed83 on January 14, 2011, 05:07:45 pm
Bought the truck this past may, No shroud. It runs 190 on a hot august day, but i dont get why it would go to 220 when its -2. It is heading fine.. Maybe the radiator is just too small?
Title: Re: Overheating Problem
Post by: Lt.Del on January 14, 2011, 06:17:41 pm
sure your temp sensor works?
Title: Re: Overheating Problem
Post by: Slammed83 on January 14, 2011, 07:34:54 pm
I dont know, Its an equus gauge. I am going to flush the radiator and see if that helps
Title: Re: Overheating Problem
Post by: beastie_3 on January 14, 2011, 08:26:44 pm
Something is wrong if it was 190 in august, but 220 in winter...
Title: Re: Overheating Problem
Post by: Slooby on January 14, 2011, 10:18:51 pm
Have you checked your fan clutch, being as you say the temp drops when driving sounds like the fan clutch not engaging right.
Title: Re: Overheating Problem
Post by: Slammed83 on January 14, 2011, 10:56:12 pm
No i have not, I will in the morning. Im just trying to eliminate possibilitys
Title: Re: Overheating Problem
Post by: Jim Rockford on January 17, 2011, 09:06:00 am
yep. 90% of the time if your truck runs warm at idle and cools off after you start driving its a sign the fan clutch is going or gone bad. Avoid the urge to install a flex fan , they are junk , just get a good replacement fan clutch.
Title: Re: Overheating Problem
Post by: benzesrule on January 17, 2011, 09:14:27 am
I had this same problem om my 84 k10 but only when the snowplow was installed. When the truck was hot, I spun the fan and it turned very free. I replaced the clutch fan and I have not had the problem again. No matter where I raised the plow, all the way up or lower, My truck never overheated since.
Title: Re: Overheating Problem
Post by: Layne on January 17, 2011, 01:55:11 pm
I had a 92 s-10 with the iron duke and it had a bad fan clutch. Sounded like an airplane. Anyway, I was 16 and didn't know too much car stuff and it zoomed right off the water pump and into my rad. That was a fun day....