no heat
Thread Starter
|
New User
Joined: Nov 2009
Posts: 7
Likes: 0
From: olcott,ny
no heat
i recently got my 1986 f150 s/c 5.8 HO.it has 88k,and is a very clean well maintained truck. years ago i had the same type of set up in a 1985 f150. problem is,lack of heat.i flushed the heater core,not much there,put in a new ford thermostat,made sure cooling system is all purged and full. when it heats it's circulating. idling it'll heat up to between '"n" and "o",with some heat,but then down the road will go to cold!? then cool heat. . what am i missing? i even tried the cardboard in front of the radiator trick yesterday,no affect
Posting Guru
Joined: Nov 2009
Posts: 2,244
Likes: 1
well u can get faulty parts that have the same problem as the one u took out. possibly opening at too low temp. may not be the case. it should be a 195*F thermostat. is that what ur running? and are u running any kind of additive in ur coolant besides anti freeze. u know like water weter or somthing of the sorts..... wow ill tell u this one has me stumped coz when i read ur first post it sounded like u wasnt running a thermostat... but u are
Elder User
Joined: Nov 2005
Posts: 834
Likes: 0
After chasing a problem like this for sometime, I now always check the new thermostat before installing.
Pan of water on the stove with a cooking thermometer. Turn on the heat and watch the thermostat and the thermometer as the water heats up. 5 minutes testing before installing can save you hours of chasing a mystery problem.
The thermostat may not be your problem, but it is really nice to know for sure.
Good Luck Frank
Pan of water on the stove with a cooking thermometer. Turn on the heat and watch the thermostat and the thermometer as the water heats up. 5 minutes testing before installing can save you hours of chasing a mystery problem.
The thermostat may not be your problem, but it is really nice to know for sure.
Good Luck Frank
Trending Topics
Fleet Mechanic
Joined: Apr 2008
Posts: 1,724
Likes: 2
From: Vancouver BC Canada
Check your water pump. Someone told me a good way to test if its flowing properly is to squeeze the upper rad hose while the truck is running. When you release it you should feel the water whoosh back. Does the upper rad hose get hot at all?
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
10 Best Ford Truck Engines We Miss the Most!
Joe Kucinski
2026 Shelby F-150 Off-Road: Better Than a Raptor R?
Brett Foote
2027 Super Duty Carhartt Package First Look: 12 Things You NEED to Know!
Michael S. Palmer
10 Most Surprising 2026 Ford Truck Features!
Joe Kucinski
Top 10 Ford Trucks Coming to Mecum Indy 2026
Brett Foote
5 Best / 5 Worst Ford Truck Wheels of All Time
Joe Kucinski
Ford Super Duty: 5 Things Owners LOVE, 5 Things They LOATHE!
Joe Kucinski
Every 2026 Ford Truck Engine RANKED from WORST to FIRST!
Michael S. Palmer
The Best F-150 Deal of Every Trim Level (XL through Raptor)
Joe Kucinski
Elder User
Joined: Jan 2008
Posts: 973
Likes: 0
From: Gatineau, Quebec
Never fun chasing a problem that should be easy to diagnose and solve.
I suspect it has to be one of three things....assuming that coolant levels are good and there is no air trapped in the system.
-The coolant obviously has to get up to temp. If the thermostat is working properly than that should not be the issue. Feeling the rad hosed should quickly tell you how hot your coolant is getting ..more or less.
-Next thing to check would be circulation. Feel the various hoses to see if they are the same temp. This should give you some indication as to whether or not you are getting the circulation from the pump or not. All the hoses should be firm as well when hot.
-If the coolant appears to get up to temp and it appears to be circulating properly, Then I would suspect a heater core problem.
Given that it gets warm and then cools off when you drive, I would suspect a faulty thermostat would be the culprit. Also, as someone else stated, make sure it is the 195 deg. thermostat.
Just my 2 cents....
I suspect it has to be one of three things....assuming that coolant levels are good and there is no air trapped in the system.
-The coolant obviously has to get up to temp. If the thermostat is working properly than that should not be the issue. Feeling the rad hosed should quickly tell you how hot your coolant is getting ..more or less.
-Next thing to check would be circulation. Feel the various hoses to see if they are the same temp. This should give you some indication as to whether or not you are getting the circulation from the pump or not. All the hoses should be firm as well when hot.
-If the coolant appears to get up to temp and it appears to be circulating properly, Then I would suspect a heater core problem.
Given that it gets warm and then cools off when you drive, I would suspect a faulty thermostat would be the culprit. Also, as someone else stated, make sure it is the 195 deg. thermostat.
Just my 2 cents....
Thread Starter
|
New User
Joined: Nov 2009
Posts: 7
Likes: 0
From: olcott,ny
thanks for all response. the thermostst put in on thursday was the 3rd.1st was probaly original.suspected faulty aftermarket,so i installed ford.all 3 195 degrees. heater core i ran water through both ways,not much "bad"came out.heater hoses are HOT.both within a couple degrees of eachother. upper hose is hot when running,lower is cooler,not cold though.cap off you can see circulation of coolant. my 86 years back had the EXACT problem.i sold it before i got to the bottom of it.thought it might be characteristic. i'm suspecting failing waterpump??or radiator?? coolant is not leaking anywhere either,lvel stays same??? thanks,scott
Fleet Mechanic
Joined: Jan 2009
Posts: 1,964
Likes: 2
From: Fort Worth
Even if this were true, if the flapper was working and the **** turned to hot, the air coming through would still blow hot.
Cargo Master
Joined: Jan 2004
Posts: 3,118
Likes: 149
From: South Dakota
I would put in a new heater core anyway. Years ago, and I mean years ago before just replacing a heater core was commonplace, my dad had a 1967 Ford car. I put in a new high-temp thermostat and changed the coolant and still had zero heat. I removed the heater core and took it to a radiator shop. The guy there ran hot water through it as he felt the cores, he then ran cold water through it as he felt the cores. He said there's nothing wrong with this. I told him to tear it apart anyway because I tried everything else. Without argument, he said okay come back in a couple hours. When I got back he said you were right, it was plugged. The heater worked good after that.
So if you otherwise get to wits end, I would replace the heater core.
So if you otherwise get to wits end, I would replace the heater core.