I have been battling this issue for a couple weeks now and it's really starting to get on my nerves. Ever since it has gotten cold here in MN my ranger wont warm up. It only warms up to operating temp while driving and when I stop at a stoplight or just let it idle the temp gauge drops down past C pretty quickly and you can feel the heat coming out of the vents get lower. While the truck is trying to warm up after i start it I can feel the top radiator hose get somewhat warm and the lower radiator hose is cold. IDK is my new t stat is maybe stuck partially open or if maybe some coolant is leaking by.

Truck info:
1997 Ranger 2.3L 4x2 5 speedI have flushed the heater core a couple times also and I do get good flow through it. I have also found that my alternator is on its way out but I dont think that has anything to do with it.

I am starting to get very frustrated with this issue as nothing seems to fix it. If anyone has any ideas that would be great!

 

This sounds like a thermostat related issue. Did you check the new thermostat to see if it works properly before you installed it?

 

nah, just assumed. maybe i will try a new motorcraft one and see if that works.

 

Not that it fixes your issue, but in alaska we put cardboard behind our grilles so that wind is deflected and our engines can heat up more/faster.

 

I have tried that and it helped it heat up a little while idling. But the truck heats up fine while driving; it is just while at idle when the temp gauge drops.

 

Since you have changed a lot of things the fluid level should be at the full point, if not fill it up.
A while back I had a problem similar, hadn’t done all the work you did, and it was the fluid level was low, very low. Something I never checked and once filled it worked great.

Have you looked at the fluid to see if it is moving around while idling ?
Also, when the engine is running and the cap is off the radiator, can you see the core of the radiator or close to seeing the core through the fluid ?

When the engine is not running, can you move the fan without slipping the belt ?

Did this temp problem start before or after the new parts ?

Last but not least is it "air bound”, hard to do but it can happen, not even sure how to fix it but maybe running the engine while checking things out might release things.

Just so you know I am guessing here, sort brain storming so these are just thoughts about the situation.

Good Luck

 

Ok, I think I figured it out. I bought a new thermostat from NAPA and it looked like it had a better rubber seal on it that the MOTOCRUD I had put in before. I got it all back together, topped it off with coolant again and it was doing the same deal. This was making me think it has to be a circulation issue because when I rev it up a little the gauge goes up and I get a little heat.

So I took it for a drive and was driving around in 3rd gear keeping the RPM's pretty high trying to push any sort of blockage free. It seemed to help a little bit but the needle would still drop a hair when I stopped. I swung into menards and grabbed a bottle of CLR and drained a little coolant out in the parking lot and dumped a little under half a bottle in. I went and drove around some more and it seemed to be getting better. So I swung over to Oreilly's figuring I would pick up a new radiator cap since the one that was on there was pretty old.

When I popped the radiator cap it released a little pressure and the radiator fluid was already turning brown. I threw the new cap on and drove around a little more and the heat was blasting HOT, like real hot. I brought her home and parked her in the driveway and the needle didnt drop any more while idling. I am going to wait for it to cool down then fire it up again and see if it warms up to temp on its own.