changing thermostat

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Sep 29, 2008 | 09:07 AM

wildstang

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From: Orange, Vermont

changing thermostat

What is the procedure for changing the thermostat and where is it located? Do I need to completely drain the coolant or is there already a procedure written somewhere and what about bleeding the air out of the system? My temp needle only gets to the line before the word normal and winter is on the way so I don't want to freeze in it. Is there a reason it runs abnormally cold? I assume when it was new it ran warmer. Thanks for any help.

Sep 29, 2008 | 09:22 AM

jle70

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From: Sullivan, IL USA

If Gauge is still accurate it should come up to the "o" on normal.
DIESELSITE THERMOSTAT FOR FORD POWERSTROKE from DIESELSITE | DirtDirectory.com
7.3L Power Stroke Coolant Changing Instructions - Engine Care & Maintenance Forum
Can't find any written instructions someone will help here, though.

Sep 29, 2008 | 09:44 AM

CampSpringsJohn

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From: Melbourne, Ky

You will need to drain the radiator about half way. It is located on the right side of the water pump. Follow the top radiator hose. The thermostat is located under the housing that is connected to the radiator hose. You will need a 10mm socket I believe, with a long extension, and possibly a swivel for the back bolt. There are 3 bolts. The new thermostat should have a rubber gasket that wraps around the outer edge of the thermostat. This is different than the original, which uses a rubber o-ring on top of the thermostat. The new design works better. It is also recommended to have the heater hose removed from the water pump when re-filling the radiator, until the water reaches the top of the fitting on the pump. This is to make sure all the air is out of the system. Removing the fan belt would make it a little easier, but it's not necessary. In fact, it may be more trouble to remove and re-install the belt, than it is to work around it.

Sep 29, 2008 | 11:02 AM

FARM69

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From: Kearney, Nebr

Camp hit it pretty well. One more thing, you shouldn't have to use silicone around the gasket. If your thermostat is the original, it would be a good idea to give it a shot of penetrating oil to loosen those bolts up.

Sep 29, 2008 | 11:14 AM

wildstang

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From: Orange, Vermont

Thanks for all the help, doesn't look to bad. Do you guys reuse the coolant or put new in to top it off?

Sep 29, 2008 | 11:30 AM

FARM69

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From: Kearney, Nebr

Quote:

Originally Posted by wildstang

Thanks for all the help, doesn't look to bad. Do you guys reuse the coolant or put new in to top it off?

That depends. When was the last time you did a coolant flush? Might be a good idea to drain it and start with new if you don't know that last time it has been flushed.

If the coolant is fairly new, simply top it off.

Make sure you use diesel engine rated coolant. This coolant has SCA's in it that help prevent cavitation.

Remember, the stock water temperature gauge is junk. It's simply an idoit gauge that tells you that the engine is cold, or your gonna blow it up. Having the needle in the position you describe is normal. Many on here put the 203 stat in and the gauge will read higher and actually increases the efficiency of the engine.

Sep 29, 2008 | 11:35 AM

wildstang

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From: Orange, Vermont

Unfortunately I don't know. I bought the truck almost 3 months ago from a used car dealer who go it from a ford dealer after the owner, I assume, traded it in. I need to try and get hold of him to find out these answers and ask some other questions.