Up and Down temp
Thread Starter
|
Senior User
Joined: Aug 2003
Posts: 229
Likes: 0
Up and Down temp
Hello,
I just changed the thermostat the other day and because of slow heating and now she heats up just fine but the temp bounces up and down between 195/200 and 175/180. It's a mechanical gauge so it can't be anything electrical. It is bugging me, it will go through the loop at idle maybe 2 times every minute and at 2000rpm it will go through the loop 3-4 times per minute. Could the new thermostat be bad??? or water pump going out maybe? how about fan clutch? This is on an 88 Ford Bronco(full size), 302 with tow package(heavy duty cooling system).
Thanks for the help
I just changed the thermostat the other day and because of slow heating and now she heats up just fine but the temp bounces up and down between 195/200 and 175/180. It's a mechanical gauge so it can't be anything electrical. It is bugging me, it will go through the loop at idle maybe 2 times every minute and at 2000rpm it will go through the loop 3-4 times per minute. Could the new thermostat be bad??? or water pump going out maybe? how about fan clutch? This is on an 88 Ford Bronco(full size), 302 with tow package(heavy duty cooling system).
Thanks for the help
Senior User
Joined: Feb 2004
Posts: 116
Likes: 0
From: Northwest
It sounds like your thermostat is opening and closing slower than normal. Make sure you always use the best quality one you can get...... Like when using a "stant", always spend the extra cash and get the "superstant" It's a better quality part within the same manufacturer.
You could also drill one or two 3/16 holes in the outer part of the replacement thermostat, this will definatley make your temps much more even. The only drawback to doing this is it may take a little longer for your motor to reach full operating temp in colder weather.
You could also drill one or two 3/16 holes in the outer part of the replacement thermostat, this will definatley make your temps much more even. The only drawback to doing this is it may take a little longer for your motor to reach full operating temp in colder weather.
Thread Starter
|
Senior User
Joined: Aug 2003
Posts: 229
Likes: 0
Sorry it took so long to post, been busy. Yes it was a bad Tstat Advanced Auto took it back and I got a Premium as a replacement. Now the temp stays right about 195-200. I was talking to a guy and kinda argued that my Bronco should have a 180 in it, now I am not arguing this but before replacing this tstat my Bronco was running 180 and did not put out very hot heat when it was cold out(5f-10f above with temp needle on 180). So what temp(180/195) should a 1988 Ford Bronco with a 302, heavy duty cooling system with tow package supposed to have?
Senior User
Joined: Feb 2004
Posts: 116
Likes: 0
From: Northwest
Book probably calls for 195 degree thermostat. Car makers run them hot for lower exhaust emissions. 180 degree would be a better choice, its easier on engine and less prone to pinging and detonation especially when towing - but no colder than that.
Your heater should blow nice and HOT with a 180. If your not getting hot air out of the heater with a 180, then there is something wrong with your HVAC system. Perhaps a partially plugged heater core, or some type of heater controll malfunction.
Disconnect the hoses that run from the engine to the heater core and flush out the heater core with a garden hose, BOTH directions.
Your heater should blow nice and HOT with a 180. If your not getting hot air out of the heater with a 180, then there is something wrong with your HVAC system. Perhaps a partially plugged heater core, or some type of heater controll malfunction.
Disconnect the hoses that run from the engine to the heater core and flush out the heater core with a garden hose, BOTH directions.
Thread Starter
|
Senior User
Joined: Aug 2003
Posts: 229
Likes: 0
I did the whole flushing thing and had to replace the heater core because of a leak. I am still not completely happy with the amount of heat, we have had some more cold weather here in Ohio and when it gets COLD out the heater does not get HOT. A coworker has a CHEVY 1500 
and we checked, his heat comes out the defroster at about 190f. I do suspect the door that controls hot and cold is not quite right on my Bronco, I will have to look into it on the weekend, it could be the cause of my heat problem.
and we checked, his heat comes out the defroster at about 190f. I do suspect the door that controls hot and cold is not quite right on my Bronco, I will have to look into it on the weekend, it could be the cause of my heat problem.
Senior User
Joined: Feb 2004
Posts: 116
Likes: 0
From: Northwest
Water is pumped directly from the top of the motor where the thermostat is right into the hose leading to the heater core. The heater core recieves full engine temp. If your running a 195 thermostat with a new heater core......... it should put out enough heat to be uncomfortable hot. Your eyes should hurt when your running the defrost. It should be so hot inside that truck when the heater is going that getting out of the truck into some cold single digit temps would be a welcome relief.
