4-Cyl. running cold

[tworanger]

I have a 1991 Ford ranger with a 2.3 liter manual. It has 164,000 mile on it and everything runs great yet. My problem is the temp gauge barely(?) makes it into the normal band in the cluster after driving 20 miles. The heat coming out of the vents is warm at best, never really getting hot. I have placed a piece of cardboard in front of the radiator with a 5"x5" hole and it still never heats up totally. I have replaced the thermostat with a 195 degree one and nothing has changed. I am no professional, but don't think the heater core could be the problem because the gauge indicates it's running cool. I know these engines never had a problem with overheating but it sure would be nice to get it warmer on cold mornings. you can ask me more questions if it would help, any ideas?

[RobbieD]

Have you flushed the cooling system out real good, with a garden hose? On one hand you may have sludge or scale buildup on the inside surfaces of the heater core, preventing a good heat exchange, but on the other hand I'm always hesitant to suggest anything more than a clean water flushing of the cooling system. Also might want to check that the blend door is fully operable, and perhaps also check that you don't have trash (leaves) blocking the air flow through the core. The heater core hoses should be getting pretty hot to the touch; are they?

[tworanger]

thanks for the advice RobbieD, Just wondering though how do you check to see if the blend door is operating properly, is there an easy way to check? Leaves shouldn't be a problem considering the truck is normally garaged and if it sits outside theres no trees near and i try to stay on top of that kinda thing. I'll have to try to touch the heater core hoses tomorrow if i get a chance. thanks again for the help

[MAKG]

Check that the coolant is cycling properly on warm-up. Mark the overflow when cold, and then warm it up and see if the level goes up. Feel the upper rad hose to see if it's pressurizing.

'Cause it sounds like low coolant.

[tworanger]

Last night decided to maybe check to see if the heater core was clogged so i drained the coolant and removed the core and i must say it looked perfect and hooked it to a hose and the water ran right through it really clean. There seems to be some small hose coming off the return line from the heater core, does anyone know where this goes, I tried to follow it and think there is a wire that comes off it(to the gauge maybe?). i shot water through the hose leading to the core and it was clean as well. The t-stat is opening up and circulating coolant but the heater stayed relatively cool to the touch as if no flow through that system.

[MAKG]

The temp gauge sender should live right behind the thermostat in the intake manifold. If it is "teed" off the heater, it's FOS.

This sounds like a hare-brained previous-owner modification.

[Dsc Motorsports]

ive had my ranger(2.3l) for about a year and it always runs extremely cool and the heater also takes a while to heat up!!

[RobbieD]

There seems to be some small hose coming off the return line from the heater core, does anyone know where this goes, I tried to follow it and think there is a wire that comes off it(to the gauge maybe?).

How does this "small hose" come off of the return line from the core? Does it go to something that's spliced inline into the heater hose? I'm not aware that a shutoff valve was used on the early trucks, but there shouldn't be any small hose coming off the heater core hose on the stock setup. Does your truck have air conditioning, and if so do you know if it's stock or aftermarket AC?

[tworanger]

When the hose returns from the heater core it routes toward the middle of the passenger side of the engine head, there is a tee(more of an elbow with a small fitting for a little hose). It looks all stock and i have no reason to suspect that it is a modification. I do have stock air conditioning. I have looked for a shut off valve and haven't found one yet, would ford have tried to hide this, on my 97 ranger with the 4.0 its up high and accessible. i have removed and flushed the line into the core, the core, and the return line(including the tee). Thanks again for all your help

[MAKG]

Sounds like a water manifold. I don't think those are stock for any RBV. It's something you might do if you have a problem with air pockets forming in the head. It shouldn't be necessary on a stock head.

Unless it actually goes to the intake manifold. That would be a heated manifold. It's useful for correcting fuel atomization problems (though I thought all RBVs used a heat stove instead).

[tworanger]

I figured i would just put everything back together and worry about it in the summer. Everything seem to be working great now. I must have dislodged something. Anyways thanks for all the help everyone