First, what happend to the search function ? I wanted to search and see if anyone encountered my problem but it seems like the search function is gone.

O.K. To the problem.

'98 Explorer A/T 4X4 4.0L SOHC engine. ~67K miles on it.

Today it started acting all wierd. The symptoms are:

- Runs hotter than usual. Before, heat or cold (I live in TX) the dial would set right in the middle of the scale when the engine would reach operating temperature. No matter what. Today it went all the way up to 3/4 and then would go from there up and down about an 1/8 of the scale.

- Engine RPM are higher than normal. It's usually around 700RPM and today it went up to ~1300RPM. A/C on or off. When I start the car (after it has been sitting around for ~30 minutes) it would set on 700RPM but then, after about a minute it would go back to 1300 again.

- Gear change (A/T) feels wierd. As if the transmission is changing too early. Gear change feels ruogher than usual.

- Wierdest thing, It was a nice day today at 73 degrees and I didn't want to use the A/C so it would not put more load on the engine as it was acting up. So I turn the air on (one click counter clockwise) and the air comes out warm. It wasn't hot but definitly not as cold as it should have been.

Other than that there isn't any noise. Engine coolent is in the right level and seems to be clean. Air filter was replaced at 50K. Last oil change was done ~2500 miles ago and I just had a new set of tires installed. No check engine light and apart from the engine temp dial everything else seems fine.

Anyone knows what the heck is going on ? Is my car possesed ?

 

your throttle position sensor may be malfunctioning.This will affect trans shifting ( usually hard shifts or erratic). Your thermostat may be sticking.

 

nope just a bad thermostat the computer is programed to do those things when it overhaets

 

Blly177,

What do you mean, do those things ? Like act all wierd and set the air temp to warm ? Idle to higher than normal ?

How do I test the thermostat ?

Thanks,
zoti

 

you have to take it out and put it in boiling water but you can replace it for 4$ the heat may be a seprate issue called a blend door.

but yes it will idle higher and shift differently

 

Thanks,

The blend door is fine. I know becasue I fixed it on my 96 B2300. A/C runs fine on regular and max. I will take the Thermostat out tomorrow and test it.

Where should I drain the coolant from ? How much coolant goes in the engine (So I can have enough buckets ready). What is the right proceadure to bleed the air out of the system ?

I have the haynes manual but it doesn't say how to bleed the system.

 

on my sohc i didn't even drain the coolant just kind of let some leak out maby a quart leaked out. to bleed it just bring it up to temprature with the radiator cap off

 

I took the old thermostat out (what a pain. It's located under the engine throttle body and was hard to get to). Put it in boiling water and it wouldn't open. I was going "yey" problem found.

So I got a new thermostat. Brought it home and wanted to show my wife how it works. Dropped it in boiling water and to my surprize it won't open as well. On the box it says it should open at 90 degrees Celcius.

Do you think the new one is broken too ? I don't want to install it before I make sure it' working properly.

 

I just got another thermostat. Brand new. Different shop and manufacturer. Drop this one into boiling water as well but it will not open.

I'm going mad here.....

 

OK. I have insalled the second thermostat and it seems to be working. I bleed the air out of the system and noticed the upper radiator hose got hot. The temperature gage is back to normal.

Thanks for you help.

 

went thur this on my '92 with 175,000mi. Replaced 2 thermostats and a water pump. Problem returned. Now I starting to suspect its a leak at the manifold or head.