I have a 92 E150 conversion van with a 5.0 EFI. The van was off the road for about two years but I put it back on the road sometime around the begining of this past winter. I changed the oil,filter,gas filter,and flushed the cooling system as best I could and refilled it.
During the winter months as they be down here in the Houston Texas area, the temp. gauge never went any further than between the "N"and"O".
All the years I've owned it during the summer time the gauge would go up to between the "R" and "M" and "M" with the A/C on.
Now that summer is rolling back in with temps here climbing back into the mid eighties, the motor is starting to get too hot, climbing up to the "L" and above. The water pump was replaced about a year before the van came off the road, so it's not that old. A few days ago out of desperation I removed the thermostat all together and flushed the system again just to see if that was my problem but it's still overheating.
Another problem has popped up in that when the temp.gauge gets up to the "R" something kicks in and the motor jumps up the idle way too high to where it sounds and feels like I'm power braking at the red lights and going down the road doing 40 without touching the pedal.After a little while of that the idle will drop back down to the point where it sometimes will stall out at a light and sometimes not, then the idle will jump back up again and so on. I've bypassed the water hose that runs through the throttle body, this is Houston, I replaced the standard fan clutch that had a 5 blade fan with a heavy duty one with a 7 blade fan and still have the same problem.
From "cold" to "O" in normal it runs great.
I've been trying to get AutoZone to pull the codes on the van for the past few weeks,but their always too busy,understaffed,or it's raining, so I'm going to try it myself using my Haynes manual this weekend. By the way, I read in the posts about how great these Haynes manuals are,and how they give you so much information and all, I bought one for "Ford full size vans 1992-1995 E150-E350 gas engine models" and I think it sucks, the pictures and or drawings of the motor don't look like what I have here in this van.They tell you to check this and that,but I can't find this or that on my engine, and if I do, it's not where they say it is or look like they say it does.
I saw a Chiltons softcover manual for this van in O'Reilly's auto parts the other day and it's pictures and drawings were just like my engine and gave much more information.When I get paid,I'm going back and buy it.($18)
One more thing, what is the best brand of cooling system flush I can use in my system that will do a really good job of cleaning out the radiator and water ports and jackets in the engine? I would like to try everything I can do before I take it to a shop and get told to bend over when it's time to pay. Thanks.

 

I would pull the IAC off and clean it, then I would replace the coolant temp sensor.

 

I was planning to check out the IAC this weekend. As far as the coolent sensor go's if thats for the temp gauge, I promise you it's overheating big time, boiling back up into the overflow tank and all.

 

If the Haynes hasn't been edited in several years, it may not really cover your year. Check the classified ads for a Ford/Helm service CD, or look on eBay. If you know anyone that has one for trucks & vans near your year, just copy their CD & install it on your computer.

You can pull the codes with a paperclip in only a few minutes, and that thread has a link to my code list.

There are 2 temp sensors: one for the gauge (with a single R/Wh wire) and one for the computer (called the "ECT" Engine Coolant Temperature sensor).

 

Somebody told me today that Chilton's either merged with Haynes or bought it outright. I saved those pages and and I'll pull the codes this weekend. The most importent thing I need to do is try and get that engine temp down because it heats up pretty fast. I think I can get to one block drain plug but I hear the other is behind the starter. I can't help thinking that the block is mucked up from setting so long and maybe the crud is starting to break up and clog the passages in the motor. The radiator gets hot,the hoses get hot and the motor gets hot,don't make sense to me.

 

The rad passages are much smaller, so it's more likely that's where any blockage would occur. When the truck warms up, let it idle & hose the radiator down for a couple of minutes and then stop, but leave the engine idling. Watch carefully how the radiator dries; if one area dries significantly faster than another, then the wet one is blocked.

Also, see if the fan can be stopped easily by hand, using a rag as a pad. Only contact the blades from the BACK (engine) side, but don't let the rag go into the belt. If you can stop it without much effort, your fan clutch may be bad.

If the overflow tank is hot, replace the radiator cap - it's only a few bucks.

 

Good idea about hosing the rad. I'll do that after I come back from the store when it should be good and hot. I'm not sure about the thing with the rag and the fan, I'd like to keep all my fingers right where they are. But now that you mention it, when it starts getting so hot the clutch should have locked and I should have heard the fan roaring away. I know what that sounds like because the old clutch was locked up all the time and made a hell of a noise, and this one has two more blades than the old one.
I thank you guys for the advice.

 

For anybody that flips through old posts, I did find that the overheating was due to a really clogged radiator. I ended up taking it to a radiator shop in town and the next day when I picked it up the guy told me that it only had about 1/5 of the normal flow of coolent through the radiator. He took the tanks off and rodded it out and flushed it out. No more overheating ! He said it was because the van had not been used for so long that rust built up in the system and then it all broke lose after a while and lodged in the radiator when I started driving it again.