98 explorer possible thermostat issue

[yavapaires]

Yeah - lots of guys don't replace radiator caps because they pass the visual test, but that's not what counts.
It's a pressure and vacuum device.
If it doesn't hold pressure, you quickly overheat. They should hold 15-16 PSI (if memory serves me correctly).
If it doesn't hold vacuum, you don't suck in coolant from the overflow tank as you engine cools down.
The little overflow hose that connects the two is regularly overlooked ;-) They clog and kink.
All the "crap" that floats to the top of the radiator gets pushed past the radiator cap, out that little overflow hose, and into the overflow tank...

Report back ;-)

PS - If your thermostat has a teeny tiny "jiggler" valve on it - that has to be facing upwards...
It's a little piece of metal (or brass) that sits loose and is allowed to jiggle around in a hole that's on the flat surface of the thermostat close to the outer edge.
Here's a pic of one gathered off the internet:
https://encrypted-tbn2.google.com/i...AYspdLHJZYsMTOS-8bGtDO177XQBxNXS5NYQUEju1tUmW

Replacement Radiator Cap: Your Ex takes a STANT 10233 Radiator Cap, rated at 16 PSI; Here's a pic of it:
http://info.rockauto.com/getimage/g...eurl=http://info.rockauto.com/Stant/10233.jpg

For Fast Dave. Thanks for the tip on the "jiggler". Ibought a new t-stat today, and sure enough, there it is. I never thought about it before because this is the first vehicle I have owned that has a vertical t-stat. If I would have looked at it, I assume it would go to the top. However the key word is IF. Now, thanks to you I know to pay attention. Thanks again

 

[fast_dave]

yavapaires,

Glad to hear I was able to help you out with that lil' detail ;-)

I've got so much great info from this forum over the years it's priceless - so it's good to hear that I was able to pass on a little of my wrenching experience!

 

[torumekian]

Once I got into tearing my car apart, I noticed the coolant was running down the side of the water pump from above. Once I could get in there and get inside feeling around the coolant was coming in from above so instead of checking the water pump I went in for the thermostat housing. Once it was out (which was a horrible job getting the cable ties cut away to get it out) on the underside was a crack about an inch long. The local o'reilley auto had one with the temp sensors included for $85. Took about 5 hours from start to finish. Was a bit of task reassembling but as soon as I got it all back together worked like a charm the first time. I'm sure I'll be topping off the coolant over the next week to accommodate the system purging itself of air.

 

[fast_dave]

Right on - good to hear that it was in stock at O' Reily's.

Pretty soon you'll be back in the game and good to go ;-)

 

[torumekian]

Yep. Did my test drive about 5 pm. Not a drip. Still smell a little hot coolant but I didn't get all of it off the block under the intake cause it was hard to reach. It'll burn off in a day or two. Thanks for all the pointers man, I appreciate it a lot. I can't upload a picture here from my phone but I'll upload the one I took of the cracked housing at work tomorrow.

 

[fast_dave]

John - cool deal. It'll take a couple of days to burn off the coolant that spilled on the block. The first rains will wash it completely off. Change your coolant every 2 years will really aid in keeping your system in top notch condition for CA summers. Oil and Coolant are the lifeblood of PRK vehicles, change them often. When you look at repair costs, oil and coolant are cheap in comparison. You lucked out that your truck is old enough that a part like that was in stock at a brick and mortar store - reason enough to drive it 'till it drops ;-)