Just bought '99 2.5 Ranger. Temp gauge was dead, tested shorting the temp sender leads - gauge read full scale. Bought a new temp sending unit, and temp gauge takes a VERY LONG time to register anything - at best, it will move up the scale about 1/8 of the way... The strange thing is, if I warm the truck, and shut off, ignition on, the temp gauge will approach what i consider to be a normal temp reading. Have tested the sending unit - boiled a cup of water, and immersed sending unit - temp gauge worked fine. I'm thinking of power flushing tomorrow to see if there is some obstruction, limiting the flow of coolant. In my mind, when I shut off the engine, coolant is somehow equalizing, and the temp sender is getting a good read of the hot coolant. Or, could there be a t-stat problem in that when the engine is running, there is an absence of coolant around the temp sending unit?? Man, this is getting tough to find!!

 

Maybe your t-stat is stuck open? If you're going to flush, pull the t-stat and put the cover back on. You'll be able to flush better plus with the t-stat out you can test it or better yet just replace it.

 

Thanks - good idea about removing - yep, i oughta get a better flush w/o it. How difficult is it to remove? Do I have to remove the entire housing that also has the temp sensors??

 

Can't tell you on the 2.5L, I've got the 3.0. On every other car I've worked on though the Tstat housing is all by itself - no need to undo any other sensors.

 

I looked online at the part - http://www.rockauto.com/ref/Motorcra...html?rh-83.gif Looks like the tstat is between the housing and engine block - and of course, the bolts don't look too easily accesible... Has any one replaced the t stat on the 99 2.5 Ranger?? TIA...

 

No, haven't had the pleasure yet, but I bought the flushing tee set from the parts store, and flushed that way. You really don't want to mess with those sensors in that plastic housing. Those brass fittings will leak,(mine already do ,and I've never ever touched them). I put the tee in one of the heater hoses. (read the back of the kit, it will help with location) Also, I switched to Peak Global 50/50 Antifreeze/Coolant. (I think the green stuff will be obsolete in a couple of years). Good luck!!

 

update - if anyone was looking for responses to this issue - replaced thermostat and gasket yesterday. Back to normal operation! FYI - it's best to use a 1/4" socket with either 3 or 6 inch extension to reach the bolts...

 

Thanks for getting back to us.

 

Hi Twinarrow99. I am looking at the same problem with our 99, 2.5 w/air. I bought a new stat but looking from the front of the engine I can only see part of one of the housing bolts. My manual is of no help whatsoever. Did you have to remove anything to gain access to the stat housing bolts or is it just a blind poke till you find it thing? Daughter has complained of poor gas mileage so I'm guessing that will improve once the engine runs at proper temp again. Thanks, Jim.

 

Howdy Nite Ranger, drain the system, disconnect the two temp sensors, and then remove both hoses. This will give you a <little> more room to work with. Buy your self an inspection mirror that is adjustable, and you will see both bolts. If I recall, they are 8mm socket size. I found 3 and 6 inch extensions with a little 1/4" driver worked the best. The bolts are diagonally opposed, so if you find one, look 180 degrees across to see the other. Also, buy a new rubber gasket for the housing! Working with a mirror is a bit awkward, but I had my son hold the mirror handle in the right place - no problemo! Be careful with torqueing the bolts - remember your housing is PLASTIC! I also noticed an improvement in mileage after the fix. (Funny story - I had the muffler replaced before I did the stat replacement, while they were torching off the old one, there was a LOUD BOOM! The truck was running way too rich - never warming up, and there was a concentration of flammable gas in the muffler - was ignited by the torch!) Man, I thought someone had shot a 12 gauge as I was standing right there! Good luck and let me know how this goes for you!