Ford Ranger Forum - Forums for Ford Ranger enthusiasts!

Go Back   Ford Ranger Forum - Forums for Ford Ranger enthusiasts! > > >
Forgot Password? Join Us!

Welcome to Ford Ranger Forum

Reply
 
Thread Tools Search this Thread

  #1  
Old 04-03-2011, 09:28 AM
jmonck jmonck is offline
Like the Forums
 
Join Date: Feb 2011
Posts: 49
Default coolant/thermostat question..

Can anyone tell me if thermostats open against coolant flow or with it. Also, is there such a thing as a weak or sluggish thermostat? My temp gauge makes some pretty wide swings between being on the throttle or coasting/cruising. It moves slowly but reliably up and down when I'm on or off the gas. Coolant is fresh and clean. I just bought the truck and the radiator was close to empty. It's definitely full now, but decreasing slowly. I think the head gasket is leaking, but I'm trying to address that in another post. Just curious about the thermostat right now. I'm hoping thats all it is. '93 4.0 OHC 4wd ~250K
__________________
1994 2.3L 2wd 5spd...just won't Die!
On Deck: 1993 4.0L 4x4 auto... hopefully
Reply With Quote
  #2  
Old 04-03-2011, 10:21 AM
FireRanger FireRanger is offline
Blinded by the light
 
Join Date: Sep 2009
Posts: 7,674
Send a message via AIM to FireRanger
Default Re: coolant/thermostat question..

The direction the t-stat moves is pretty irrelevant. It varies between closed and wide open to maintain ~190 degrees. Wild swings in temperature usually mean it isn't working right at all. It can also happen when your coolant is low. And if you're head gasket is leaking, that is adding pressure and removing coolant, which is also not going to help anything.
__________________
(Formerly)
FireRanger
2003 Edge 4.0 4wd

How to: Aux light wiring, relays, & fuses
Info: 300+ intake threads here on FRF
Info: HID Projectors
How To: NO HEAT Troubleshooting Guide
Reply With Quote
  #3  
Old 04-03-2011, 10:25 AM
matt224 matt224 is offline
Ford Ranger Driver
 
Join Date: Jan 2011
Posts: 591
Default Re: coolant/thermostat question..

The Thermostat opens and closes with a spring, so it is possible that the spring gets gummed up or just loses tension. It is a relatively cheap part and easy to install, so I would recommend changing it out (do you know whent he thermostat was replaced last?). Usually your tem guage should remain in relatively the same place, it might read hotter if you are idling in traffic for long.

----------

I should also ask, when was the last time you flushed the system? Just adding new coolant might leave chunks of old crap behind.
__________________
2006 Fx4 Level 2 with a 5spd, Superlifted on 33's.
Reply With Quote
  #4  
Old 04-03-2011, 12:28 PM
jmonck jmonck is offline
Like the Forums
 
Join Date: Feb 2011
Posts: 49
Default Re: coolant/thermostat question..

Thanks guys, I just bought the truck and I have no idea when the last time anything was done. My thinking was that the spring was weak and couldn't push/pull against any extra pressure generated from chugging uphill. Head gasket seems very likely as well, but I'll try the thermo first. I'm hesitant to try a head gasket job by myself.
__________________
1994 2.3L 2wd 5spd...just won't Die!
On Deck: 1993 4.0L 4x4 auto... hopefully
Reply With Quote
  #5  
Old 04-03-2011, 05:58 PM
Botta Ranger Botta Ranger is offline
Ford Tough
 
Join Date: Jan 2011
Posts: 240
Default Re: coolant/thermostat question..

Quote:
Originally Posted by jmonck View Post
Thanks guys, I just bought the truck and I have no idea when the last time anything was done. My thinking was that the spring was weak and couldn't push/pull against any extra pressure generated from chugging uphill. Head gasket seems very likely as well, but I'll try the thermo first. I'm hesitant to try a head gasket job by myself.
Some mechanics use a chemical test of the antifreeze to detect exhaust gas and therefore head gasket or crack. Don't know how reliable. You have removed the radiator cap and looked for a bubble stream of exhaust gas?
Reply With Quote
  #6  
Old 04-04-2011, 08:07 AM
jmonck jmonck is offline
Like the Forums
 
Join Date: Feb 2011
Posts: 49
Default Re: coolant/thermostat question..

No I haven't done that. I did check the reservior for bubbles though. Never noticed any while it was running. I did see some after it was shut off, only happened once though.
__________________
1994 2.3L 2wd 5spd...just won't Die!
On Deck: 1993 4.0L 4x4 auto... hopefully
Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
coolant thermostat 180 or 190? CLOS99 3.0 Vulcan Tech 2 01-27-2011 08:53 PM
Thermostat Torque question USMC Dude 3.0 Vulcan Tech 2 11-30-2010 09:57 PM
Replace Thermostat 1994 2.3 question The Toolman 4-Cylinder Tech 3 07-31-2010 06:38 AM
thermostat question daniel.kezele 4.0 SOHC / 4.0 OHV Tech 1 04-20-2010 02:04 PM
1997 Ford ranger 2.3L thermostat Question? Justin J General Ford Ranger Discussion 2 01-03-2009 07:58 PM