84 c4 overheating help
Thread Starter
7th Gear
Joined: Apr 2012
Posts: 7
Likes: 0
From: San Leandro, CA
84 c4 overheating help
i have an 84 c4 cfi. it has about 130,000 miles on it. what can i do to get it to run cooler right now on the freeway it runs at about 200 but around town it runs between 210 an 220 but at a red light sometimes it'll get up to 240 the fan kicks on at 210 so what can i do to make it run cooler thank you for the help
Race Director
Joined: Dec 2000
Posts: 17,551
Likes: 26
From: El Paso Texas
i have an 84 c4 cfi. it has about 130,000 miles on it. what can i do to get it to run cooler right now on the freeway it runs at about 200 but around town it runs between 210 an 220 but at a red light sometimes it'll get up to 240 the fan kicks on at 210 so what can i do to make it run cooler thank you for the help
Seriously, remove your radiator and clean off the front of it. Yes, you have to remove it to do this, and no, it isn't difficult. You'll be amazed at what you find on it.....28 years of accumulated crap that's blocking airflow.
Report back with your new temps when you're done.
BTW....your temps aren't that far out of the norm. My 84's temps were around 180 degrees cranking down I-15.
Melting Slicks
Joined: Nov 2005
Posts: 2,736
Likes: 0
From: WAY UPSTATE NY
Shut it off.
Seriously, remove your radiator and clean off the front of it. Yes, you have to remove it to do this, and no, it isn't difficult. You'll be amazed at what you find on it.....28 years of accumulated crap that's blocking airflow.
Report back with your new temps when you're done.
BTW....your temps aren't that far out of the norm. My 84's temps were around 180 degrees cranking down I-15.
Seriously, remove your radiator and clean off the front of it. Yes, you have to remove it to do this, and no, it isn't difficult. You'll be amazed at what you find on it.....28 years of accumulated crap that's blocking airflow.
Report back with your new temps when you're done.
BTW....your temps aren't that far out of the norm. My 84's temps were around 180 degrees cranking down I-15.
...Pull it an clean it,also clean the A/C condensor the best you can...Temps aren't far from normal..
Advanced
Joined: Jan 2012
Posts: 52
Likes: 0
From: Patterson California
Or buy a new one. Autozone has them for $135. I'm buying a new one next week for my 84
http://www.autozone.com/autozone/par.../N-ik2p1Z9pdak
http://www.autozone.com/autozone/par.../N-ik2p1Z9pdak
Racer
Joined: Oct 2010
Posts: 403
Likes: 5
From: West Palm Beach FL
As already stated, the temps are pretty much normal......
Mine are the same....i cleaned my rad about a year and a half ago.....wasnt much in it.....didnt change the temps.....I think the only real cures are a lower thermostat, lower fan switch and bigger radiator (more rows).
Mine are the same....i cleaned my rad about a year and a half ago.....wasnt much in it.....didnt change the temps.....I think the only real cures are a lower thermostat, lower fan switch and bigger radiator (more rows).
Drifting
Joined: Jan 2007
Posts: 1,908
Likes: 3
From: Supreme Soviet Peace-Loving Pipple's Kollektive of Seattle Wa
I clean out the rad every year as well as clean out the ac fins and rad fins, and after replacing t-stat I still run a cool 200 to 205 in freeway speeds and about 230 in traffic. Hot runners cook a lot of crap out.
Race Director
Joined: Dec 2000
Posts: 17,551
Likes: 26
From: El Paso Texas
Or buy a new one. Autozone has them for $135. I'm buying a new one next week for my 84
http://www.autozone.com/autozone/par.../N-ik2p1Z9pdak
http://www.autozone.com/autozone/par.../N-ik2p1Z9pdak
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Racer
Joined: Mar 2009
Posts: 251
Likes: 1
From: Windsor Connecticut
temperature
You could replace the Temp.Sensor with one that tricks the computer and makes the cooling fan come on earlier,when on the highway the car will run around 185 to 190 in traffic between 190 to 200. I purchase mine from Ecklers about 4 years ago
Intermediate
Joined: Feb 2007
Posts: 28
Likes: 0
From: PA
Although... it doesn't trick any computer on an 84 since the fan runs completely on the temperature switch.
The stock one switches on at around 230 degrees which is WAY too hot and only did that so GM could meet emissions standards. (But replacing with the lower temp does not effect your car if your state does emissions testing.) Since yours switches at 210 someone probably already replaced it at some point but as they corrode they become less accurate.
I've also replaced the thermostat when mine failed "closed" with one that opens at a lower temp to improve cooling and if it "Fails" does so in an open position so coolant still flows.
Simple preventative maintenance :-)
Its a good idea to also upgrade to the more reliable fan relay. The kit that has the male connector and relay is around $20
Its on the driver's side fender pretty much opposite the fan temp sensor on the engine block.
Last edited by CorvetteArchives; May 15, 2012 at 01:43 AM.
Racer
Joined: Feb 2012
Posts: 442
Likes: 23
From: Seattle Washington
Just another thought. My 85 seemed to have a high temp problem. 238 in traffic. Had the coolant checked with an independent thermometer and found the cololant temp was 15 degrees less then the display. Still going to remove the rad and flush the system and install a new stat.
Instructor
Joined: Feb 2012
Posts: 187
Likes: 1
From: Rockford Michigan
Just another thought. My 85 seemed to have a high temp problem. 238 in traffic. Had the coolant checked with an independent thermometer and found the cololant temp was 15 degrees less then the display. Still going to remove the rad and flush the system and install a new stat.
Drifting
Joined: Jan 2007
Posts: 1,908
Likes: 3
From: Supreme Soviet Peace-Loving Pipple's Kollektive of Seattle Wa
Le Mans Master
Joined: Nov 2009
Posts: 6,882
Likes: 234
From: Bangkok, Thailand
It's also possible that your thermostat is stuck open. When that happens the water/coolant doesn't cycle but instead constantly flows through the system. It doens't get enough time in the radiator to shed heat and you end up with excessive temps.
On the 84 it's easy enough to pull the water neck and check the stat. You can put it in a pot of hot water on the stove with a thermometer to see when it opens - if it's not already stuck open. If you need to replace it make sure to get a "Robert Shaw" (also called a "Balanced") sytle thermostat. They are a couple bucks extra, but they work much better than the cheapie stamped ones.
On the 84 it's easy enough to pull the water neck and check the stat. You can put it in a pot of hot water on the stove with a thermometer to see when it opens - if it's not already stuck open. If you need to replace it make sure to get a "Robert Shaw" (also called a "Balanced") sytle thermostat. They are a couple bucks extra, but they work much better than the cheapie stamped ones.
Racer
Joined: Feb 2012
Posts: 442
Likes: 23
From: Seattle Washington
From cold temp to hot, your coolant should expand into the recovery tank. If not I doubt your temps are as indicated on the display. Do as I did and check the coolant temp with a thermometer. I have never had the idiot light come on.
Instructor
Joined: Feb 2012
Posts: 187
Likes: 1
From: Rockford Michigan
Thanks. G
Heel & Toe
Joined: Jul 2009
Posts: 22
Likes: 0
Am encountering a similiar problem, upon reaching my garage yesterday afternoon ... the temp was almost 250, several revs dropped it to about 243, the fan was on but i didnt think it wise to let it sit and idle in the garage. Turned it off let it sit a bit, topped off the anti-freeze, too topped it actuaully, and then went for about a 3 mile jaunt. Got back to garage, it quickly went back up to about 240, fan kicked in and brought it down to about 230 stayed there a minute or 2 before i turned it off again. Although in the comments above this may be normal but a couple weeks ago it was running on highway at about 192... Do I try yanking the radiator out and cleaning the front of it....or....having someone check the water pump or thermostat....? Seems like a lot of variables...ps no idiot light...when does that come ...? about 1000 degrees...?