Rob 77

Hello all,
I am new to this particular forum, and I have done a general search of my topic. I have tried several of the recommendations that I have found, but I am not having any luck.

I have a 1992 F150 XLT, 5.0 liter V8. I have been trying to change the change the thermostat on it for two weeks now. I have successfully removed the top bolt from the thermostat housing. I am having no luck with the lower housing bolt. I have tried, ratchets in every configuration (with extensions, flex heads, etc.), wrenches (flex heads, regular, ratcheting, etc.). I even went to Auto Zone and bought one of those long flexible spring socket attachments, which broke. I have removed the nearby hoses, but most of the issue is the water pump below has a completely useless metal piece that is in the way.

One person I talked to said that there is a special wrench specifically for this job, but I cannot find it anywhere. Can anyone please help me out with some recommendations.

mikeaj92

I just did thermostat on my 5.0 few days ago. The left one is cake and the right one (DS) is tough but a 13mm 12point worked for me. Whatever size, use a 12point.

Chris_1

iTrader: (1)

Use a wrench. You might have to bend it to make it work. Hopefully you don't break the bolt if it's that tight.
That's the biggest way to tell a 302 from a 351 - on a 351 you can stick a ratchet and extension right in there; 302 there's no way.

mustangGT90210

To do mine, I used the circular side of a combination wrench. Took a while but got it. I put the wrench around the bolt, turned it the little bit I could, pulled the wrench back till it hit the metal on the water pump area, re-adjusted wrench, repeat. When it was finally fully loosened up, I was able to remove the thermo housing with the bolt still resting through it, with the wrench still around the bolt.

To re-install, put the wrench around the bolt head, and put the bolt through the thermo housing and tighten in the same fashion as it was loosened up.

Rod Wise

Rob, you think it's fun accessing that bolt with a wrench? Wait until you try to get that thermostat seated correctly in the reinstall! There are tricks to make it easier, but it is always a PITA to get it correct and no leaks!

mikeaj92

Yup. I played with it for 20 minutes trying to gwt it right. I ended up not trusting it, and ruining new gasket. I smeared some gasket silicone very thin and glued on the gasket, which holds the thermo in place. No leak yet!!

Rob 77

Thank you for the information. I had tried a combination wrench, it just wasn't working. I ended up shaving a little off of the wrench and it worked just fine. Of course now there is a slow leak. I am going to have to take it off again and use a silicone or something to get a better seal. That will come later though, it is a very slow leak.

The bad part is that it did not fix the problem. The engine temperature still drops when idling. The only time I get hot air from the heater is when I have my foot on the accelerator. Any suggestions?

qdeezie

What temperature thermostat are you using? Also, it sounds like you might have a vacuum issue.

Rob 77

I am using 195 degree thermostat. It is OEM according to the guy at the local auto parts store.

I am not sure if it was a vacuum issue, as I said I am not very mechanically inclined. I was able to fix it though. After doing some more research on here I realized that I never "burped" the radiator. After I did that, it worked perfectly. No leaks, heater works great, and engine maintains a constant temperature.