Notices
1997 - 2003 F150 1997-2003 F150, 1997-1999 F250LD, 7700 & 2004 F150 Heritage
Sponsored by:
Sponsored by: Auxito

Thermostat change

Thread Tools
 
Search this Thread
 
Old Nov 21, 2010 | 11:37 AM
  #1  
jeffreymo's Avatar
jeffreymo
Thread Starter
|
New User
Joined: Feb 2009
Posts: 3
Likes: 0
Thermostat change

This will probably be the dumbest question that you see on here today, but I have some questions concerning the thermostat on my 98 4.6 F150. The old one that I took out matches the one going in, but once I start tightening the bolts down, the black gasket on the outside of the thermostat starts to bind up, causing it to leak. It also came with an O-ring, but I do not see an obvious place for this to go, and there was not one on the old thermostat. The Haynes manual I have is not much help, as it states to "install the new O-ring into the intake manifold or on to the thermostat housing". It almost looks like the thermostat should fit down into the manifold, but this one sits on top of the manifold (barely). Am I making way more out of this than it really is? I wouldn't think that the thermostat is wrong, since the one that came out is exactly the same.
Thanks in advance.<!-- google_ad_section_end --><!-- / message -->
 
Reply
Old Nov 21, 2010 | 12:57 PM
  #2  
galaxie641's Avatar
galaxie641
Postmaster
Joined: Nov 2006
Posts: 4,517
Likes: 3
From: SE Wyoming
The T stat lays in the intake then the O ring lays on top, it should then be flush with the top of the intake. Here are a few pics:



 
Reply
Old Nov 21, 2010 | 01:22 PM
  #3  
jeffreymo's Avatar
jeffreymo
Thread Starter
|
New User
Joined: Feb 2009
Posts: 3
Likes: 0
Thank you, the pics help a bunch. My thermostat came with that black gasket/O-ring wrapped around the edge of the thermostat, and that was what was throwing me. The thermostat would not fit down into the intake with it on like that, but according to your pics, it sits on top of the thermostat instead?
It also came with a seperate O-ring. Does that one go between the intake and the thermostat?
 
Reply
Old Nov 21, 2010 | 01:52 PM
  #4  
KhanTyranitar's Avatar
KhanTyranitar
Postmaster
Joined: Oct 2009
Posts: 3,432
Likes: 7
Sounds like you have the wrong thermostat and gasket.

Buy a genuine Motorcraft thermostat and gasket. RockAuto Auto Parts sells them. The aftermarket ones make a lot of assumptions and design changes that are not called for. They are substituting an universal application thermostat and trying to make it work in a wider array of applications instead of actually making a thermostat specifically for your vehicle. The genuine Motorcraft thermostat will fit better, last longer, and will function properly in your vehicle.
 
Reply
Old Nov 21, 2010 | 02:17 PM
  #5  
93 mix 'n match's Avatar
93 mix 'n match
Posting Guru
Joined: Mar 2009
Posts: 1,845
Likes: 1
From: Montague, NJ
you need a vehicle specific gasket. its an orange O ring. costs $2 at napa. the black gasket is for universal applications. there is only 1 gasket. it goes manifold>tstat>o ring gasket>elbow. the tstat sits in the manifold, the o ring goes on top of the tstat, the the elbow bolts down.
 
Reply
Old Nov 21, 2010 | 02:19 PM
  #6  
galaxie641's Avatar
galaxie641
Postmaster
Joined: Nov 2006
Posts: 4,517
Likes: 3
From: SE Wyoming
1 O ring/ gasket and yes it sits on top of the thermostat. IIRC the T stat housing has a little groove that will go down and squish it when it is all tightened down.
 
Reply
Old Nov 21, 2010 | 02:25 PM
  #7  
jeffreymo's Avatar
jeffreymo
Thread Starter
|
New User
Joined: Feb 2009
Posts: 3
Likes: 0
Thanks guys. I put it back together, without the black gasket, with the O-ring on top of the thermostat, and all is well now, no leaks!
Thanks to all of you on your help!
 
Reply
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
basstardo
6.0L Power Stroke Diesel
12
May 9, 2017 10:19 PM
garydmundy
1999 - 2003 7.3L Power Stroke Diesel
6
Apr 22, 2017 03:45 PM
smallello
1948 - 1956 F1, F100 & Larger F-Series Trucks
10
May 7, 2016 09:31 PM
northwindone
Modular V10 (6.8l)
8
Mar 12, 2013 10:05 AM
Dino195
1997 - 2003 F150
4
Aug 15, 2012 05:26 PM




All times are GMT -5. The time now is 10:06 PM.

story-0
Rezvani's Latest Post-Apocalytic Monster Is a Ford F-150 Raptor Underneath

Slideshow: Called the Fortress, the 850-horsepower pickup combines Raptor underpinnings with military-inspired features, survival equipment, and a starting price of $285,000.

By Verdad Gallardo | 2026-05-30 18:33:59


VIEW MORE
story-1
Top 10 Most Expensive Ford Trucks Ever Sold on Bring a Trailer

Slideshow: 10 most expensive Ford trucks ever sold on Bring a Trailer.

By Joe Kucinski | 2026-05-27 16:24:34


VIEW MORE
story-2
2027 Ford Super Duty Buyer's Guide (Every Model, Engine, & Package)

Here's everything that has changed for the latest model year.

By Brett Foote | 2026-05-27 16:17:28


VIEW MORE
story-3
Top 10 Ford Truck Tragedies

Slideshow: Top 10 Ford truck tragedies.

By Joe Kucinski | 2026-05-18 19:34:33


VIEW MORE
story-4
AEV FXL Super Duty - the Super Duty Raptor Ford Doesn't Make

And it might be even better than that.

By Brett Foote | 2026-05-18 19:26:42


VIEW MORE
story-5
Lobo Vs Lobo: Proof the F-150 Lobo Should Be Even Lower!

Slideshow: Does lowering an F-150 Lobo RUIN the ride quality?

By Michael S. Palmer | 2026-05-18 19:20:37


VIEW MORE
story-6
Ford's 2001 Explorer Sportsman Concept Looks For a New Home

Slideshow: Ford's bizarre fishing-themed Explorer concept has resurfaced after spending decades largely forgotten.

By Verdad Gallardo | 2026-05-12 18:07:46


VIEW MORE
story-7
10 Best Ford Truck Engines We Miss the Most!

Slideshow: The 10 best Ford truck engines we miss the most.

By Joe Kucinski | 2026-05-12 13:09:47


VIEW MORE
story-8
2026 Shelby F-150 Off-Road: Better Than a Raptor R?

Slideshow: first look at the 810 hp 2026 Shelby F-150 Off-Road!

By Brett Foote | 2026-05-12 12:50:07


VIEW MORE
story-9
2027 Super Duty Carhartt Package First Look: 12 Things You NEED to Know!

Slideshow: Everything You Need to Know about the 2027 Super Duty Carhartt Package!

By Michael S. Palmer | 2026-05-07 17:51:06


VIEW MORE