Notices
1987 - 1996 F150 & Larger F-Series Trucks 1987 - 1996 Ford F-150, F-250, F-350 and larger pickups - including the 1997 heavy-duty F250/F350+ trucks
Sponsored by:
Sponsored by:

a/c

Thread Tools
 
Search this Thread
 
  #1  
Old 07-15-2003, 11:10 PM
rje053103's Avatar
rje053103
rje053103 is offline
New User
Thread Starter
Join Date: Apr 2003
Posts: 17
Likes: 0
Received 0 Likes on 0 Posts
a/c

for the last few weeks each time i turn on the air conditioning in my 92 f150 the thermostat flies up in a matter of two minutes or so i was wondering what the problem might be
 
  #2  
Old 07-16-2003, 10:26 AM
jim henderson's Avatar
jim henderson
jim henderson is offline
Postmaster
Join Date: Mar 2001
Location: So Cal
Posts: 4,968
Likes: 0
Received 3 Likes on 3 Posts
a/c

Maybe a couple things. When AC is on, it dumps heat in front of the radiator which of course picks the heat up and raises water temp, normally not noticable. The AC also puts a bit of load on the engine which also would create heat, but normally not noticable.

What may be happening with you is that the radiator or engine cooling passages are starting to clog and the cooling capacity is marginal. A good chemical flush might fix the problem.

The other thing is maybe your T'stat is margina and only opens up all the way when the heat load goes over the setting of the T'Stat.

Another possiblity is that the fan thermostatic control may be getting flakey and the fan doesn't kick in until the heat load is higher than desired.

Also what do you mean flies up? If it moves up say maybe to the next tick mark on the gauge and then settles back down I might not worry too much. If it kicks from normal to very high then I would start looking for the problem.

I assume you have plenty of 50/50 mix coolant.

Good Luck,

Jim Henderson
 
  #3  
Old 07-16-2003, 04:09 PM
lexluthr69's Avatar
lexluthr69
lexluthr69 is offline
Senior User
Join Date: Jan 2003
Location: Newport News USA
Posts: 383
Likes: 0
Received 0 Likes on 0 Posts
a/c

When Jim says that the a/c is dumping hot air in front of your radiator, he means that any of the cool air that would normally pass THROUGH the a/c condenser is now getting heated before it hits the radiator, therefor not doing a whole lot of cooling. I would check both the condenser and the radiator fins to ensure that they are nice and clean and free of any and all debris. It's not unheard of to get a bunch of crap lodged between the condenser and the radiator.
That's just one possiblity. It can very well be anything else to include what Jim described.
Luke
 
  #4  
Old 07-16-2003, 07:17 PM
TexBand's Avatar
TexBand
TexBand is offline
New User
Join Date: Oct 2002
Location: Texas
Posts: 20
Likes: 0
Received 0 Likes on 0 Posts
a/c

Mine did the same thing (91 F150 5.0)....significant temp rise when I turned on the a/c. It was the fan clutch.
An easy fix, and you'll be back cool again. Of course, I was ready to check the radiator for clogging, thanks to the heads-up from the FTE gang.
Thanks!
 




All times are GMT -5. The time now is 05:58 AM.