I have read that there are 2 different thermostats for ford power stroke diesels. My truck is a 95 f350 4x4, four door. I think it has highway gears, if that could mean anything. I have changed the water pump. I am reading that one water pump takes a long stem, and one takes the short stem? I've read something about the back cylinders not getting enough flow with the wrong thermostat. my truck seems to be getting hot, especially since putting on the new water pump. And, especially when pulling a load. Not much of a load either. My temp gets all the way up to 7/8 if the safe range. It runs at about 5/8 of the safe range with no load. I did put a new thermostat in at the same time. How do you tell which water pump you have, or which thermostat you need. I'm not trusting the parts store at this time, so I'm turning to you guys. Since, all you have plenty of experience with older power strokes. Also, is there any way to purge the air out of the cooling system? I hate the fact that trucks do not have radiator caps anymore, just reservoir caps. I am fixing to install a temp gauge, because I don't trust factory gauges. What actual temp should my truck be running at? And, what is too hot? Temp wise. Thanks for any input. I don't want to hurt my truck, I love my truck! Please help!

 

And, thinking ahead. Where is a good place to tap in the manual temp gauge to the engine?

 

There is a pipe plug on the driver side of the pump right under the t-stat that you can use for water temp, but you need to make sure that the sending unit does not interfere with the t-stat operation as that plug goes right into the t-stat area of the pump. Which t-stat you need at this point depends on which water pump you actually put in the truck.

1994.5-1995 water pumps used a 203* short stem thermostat.

1996 and up water pumps used a 195* long stem thermostat.

If you put a short stem t-stat in a long stem pump, the bypass disc would not seat against the bypass in the pump, so hot water would have the ability to bypass the radiator and go right back into the engine. I'm not sure if it's even possible to put a long stem t-stat into a short stem pump. I've never actually swapped the thermostats between the two.

Anyways, it is possible to interchange these water pumps, so you might have accidentally installed a late model pump on your truck and installed a short stem t-stat.

Also, keep in mind that the stock gauge in the dash isn't really accurate at telling how hot the coolant really is, so verify your water temps with a gauge like you mentioned in your 2nd post.

 

Is there a way to tell which pump I have? I just went to oriellys and told them what year my truck was, they gave me a pump, who know which one? Can you tell by the thermostat hole?

 

early pumps (short stem) have the lower hose pipe molded to the pump
newer pumps (long stem) have the pipe that bolts on to the water pump

as for the temp gauge I was watching mine today, factory gauge was below the N (NORMAL) isspro gauge was 190, last week factory gauge was at R and isspro gauge was at 190

most people use the plug on the driver side of the water pump just under the thermostat for the gauge

 

This is a long stem thermostat trying to fit into a short stem water pump. Now, if its the other way around, it won't be so obvious!

 

Thanks for the info guys. I am going to work hard on this thing today, to try and get it resolved. I am leaving out of town working again Sunday night. I have no choice but to take this truck with the trailer. So, I really need to get it done, or baby it for 330 miles Sunday, 140 miles Tuesday and 450 miles Wednesday. LOL Nice thing is, that I have another truck, that is going to become my work truck soon. Its a 95 PS dually. Lower gears, flat bed, etc.. More suited to my needs. It just needs a little polishing up. Then, this truck will be just for personal fun. And on the list for getting really fixed up!

 

Are you talking about here?

It might be easier here? Would this hole work?

 

Gander at this Fuel Filter. Could this cause it to overheat? Pretty dirty. Looks like the guy that supposedly put in new O-rings on my injectors, didn't change my fuel filter. Or he didn't change the leaky O-rings. I put in a new filter, gonna check it in a few days, and see what it looks like.

 

Well here is the tstat, before boiling.

And here it is @ 210+ according to my thermometer. The water is boiling. Doesn't look like any change to me. How much should it move? It is a new tstat, I put in about 6 months ago. Maybe this is my overheating problem? It is stuck in the cold position, I'm assuming.

 

Here is another pic, that you can see better.

 

The churning water makes it impossible to see enough detail to know whether it's open. Try removing it with a pair of tongs and taking a pic of it right away while it's still hot.

 

Called ford house, gonna pick up a new tstat tomorrow. All I can get from ford is a 195. Should get me back on the safe side though.

 

It didn't move at all. Parts guy at ford said it should move a significant amount. Im gonna throw that new one in the pot, in the morning. Just to see how far it moves. and to make sure it works.

 

Can I use this plug for my Temp Gauge? Or does it have to be the one in the side?