Hi y'all -- Just bought my 2003 ranger and I think I got a bit had...I'm a moderately experienced amateur mechanic so I think I can take care of this myself but would love some extra opinions. Seems like I came to the right place...

Here's the problem: When I test drove the truck the coolant was full and clean, and both heat and air worked well. A few weeks and maybe a hundred miles later I noticed first that the heat wasn't working, just cold air blowing out the vents. If I revved real high it would get hot for a minute, but cool right back down. Engine temp looked normal, just no heat. When I got out I could already smell coolant. Popped the hood and the reservoir was nearly empty. Upon further inspection, I found coolant dripping rapidly from the crossbeam under the engine.

And my diagnosis so far: Upon further inspection, it looks like the leak is coming from the water pump, although I haven't removed anything yet and can't see for sure with the pulley on. I can't find any sign of leaking above the pump and there's no coolant in my oil, so at least I think the head gasket is OK. There are some tiny black specs in on the inside walls of the reservoir but I don't really think it's oil either.

My idea is to get the pulley off the pump to make sure that's the culprit, and if so replace the pump.

My questions are:

- Am I missing something? Is there other stuff I should check or do first?

- Would a bad pump alone explain the heat not working? It feels like the top hose to the heater block is hot but the bottom is not, which sounds like a clog. Maybe it's just a partial clog so it worked before the pump went out? Or maybe air got trapped when the coolant level dropped, though I did try to burp it when I refilled...

- Do I need to buy the motorcraft pump? Bosch and ACDelco are about half the price.

- Anything else I should do or change out while I have the fan and belt removed?

- Does any of this point to worse problems the previous owner might have hidden from me? He seemed like a real standup guy, and I didn't see anything dripping when I test drove. On the other hand it was a rainy day and I could have overlooked it, and it would be a hell of a coincidence if the leak sprung in the short time since I bought it. Seems more likely that he topped off the coolant and hoped I'd be fooled (in which case, I guess I was...).


Sorry for the long post, just trying to get all the details in. Sure I forgot some anyhow, let me know if so. Thanks much in advance!

Ryan

 

Yes, most likely water pump, it has a weep hole that will start leaking coolant if pump seal starts to fail, not uncommon on any engine.

How many miles on the engine/truck?
You may want to change the timing belt/tensioner while you have it apart.

As far as the heater working and not working, that is normal when you have a leak in the engine part of the cooling system.
What happens with a leak is that the normal in and out to the overflow tank is thrown off.
When coolant heats up it expands, this is what creates the pressure in a cooling system.
When pressure exceeds the 14-18psi of the rad cap, it's larger valve opens and vents coolant(pressure) to overflow tank.
As coolant cools down it shrinks, and the small valve in the rad cap opens and coolant is sucked back into rad from the overflow tank.
This all relies on a sealed cooling system, a leak means it is no longer sealed.

The leak will of course leak coolant out, BUT it can also suck air in as coolant cools down, air will also be sucked in if overflow tank runs dry.
Air, of course, is lighter than coolant so it will rise to the top, and if you look at the layout of the engine and heater hoses/core you will see it is a high point.
So the air coming in from the leak will collect in the heater hoses and core(the higher point), this forms an "air block" which prevents coolant from flowing thru the core(heater blows cold).
Reving the engine can break this "air block"(heater gets hot again).
But it can repeat until air is purged out of the system, and that can't happen until leak is fixed.

Back flushing heater core is always a good idea anytime you have to drain the cooling system.
The warmer hose is the IN hose on the heater.
You want to have water flow backwards through the core to push out any debris that may have come in and got stuck in the tubes, so use garden hose on the OUT hose, and point IN hose at the ground, or into a bucket if you want to see what comes out.
Don't need alot of pressure, the flow will push out anything that able to be pushed out.

 

Thanks much for the quick and thorough reply, Ron. You just did a better job explaining that than a whole day of my cobbling bits and pieces together from the internet. I really appreciate the explanation.

Oh, and there's 130k miles on the truck. Timing belt hasn't been changed before, I think.

 

Go to your local auto parts store and rent a pressure tester. Its a pump that attaches to your radiator cap/reservoir cap (I think you have a sealed radiator). Then apply around 15 psi of pressure to the system. if there is a leak the pressure will drop over a short amount of time.

This pressure in the system also makes it easier to spot a leak.

 

At 130,000 miles I would change it.
Some manuals suggest inspection at 120k, others change at 100k, lol, so even Ford can't make up their mind.

The 2.3l is a non-interference engine, which means the valves and pistons never occupy the same space in the cylinder, so timing belt slipping or breaking will not cause major engine damage, but engine will stop working.

If you decide to change the belt, once you get down to the removal of the old belt you should rotate the engine manually and line up the timing marks, remove 1 spark plug from each cylinder, that will make it easy to turn the crank.
With timing marks lined up BEFORE removal it will be easier for you to line them up after new belt is in place.

 

Thanks again to you both for the tips. It will be at least the weekend before I can get to the repair but I'll let you know how it goes.

Can you recommend brands for the parts, and also if I should use any kind of gasket sealer when installing the pump? I saw some folks recommending RTV, others swearing against it.

 

Gasket sealer is fine to use in moderation.

When assembling a new engine at the factory they are dealing with super smooth and clean surfaces, so no sealer is used(except on oil pan, lol, Ford still can't make a good seal on those without sealer).
So using sealant is often needed, it is never a "bad" thing if done correctly.

After removing old pump clean the engine surface as best you can.
Apply some sealant to new pump, very thin, so it will hold gasket in place, put gasket on pump.

Then apply thin coat to engine side, not much, but no gaps.
Worst thing is too much and when you torque bolts down, little beads of sealant will be pushed inside pump housing, these will fall off over time and clog heater core or rad tubes.


Do NOT use a high output water pump on a 2.3l, they can barely keep themselves warm on a cool day, lol.

I have never priced out "discount" 2.3l parts over Ford OEM parts.
If the water pump and timing belt in there now are original Ford parts then you know they will last at least 130,000 miles.

 

Thanks everyone for the pointers. Changed the pump over the weekend and now no more leaking and the heater is hot as hell. The photo-tutorial on this site is about right on, including the recommendation to spend the extra few minutes dismounting the PS pump to get some more room.

Even with the PS out of the way it still took me several hours monkeying around to get the damn water pump out. I think my difficulty was that the O-ring that seals the thing in got pulled out of its seat early in my removal attempt and was then wedging the pump in really tight. When I finally got it out it was stretched to about twice its original size.

Anyway, once I had it out the new one popped in in few minutes and I was good to go. Ended up using a little grease to lube the O-ring, and a dab of RTV on the bolts even though I'm pretty sure they don't seal anything. For the record there's no gasket involved on the 2.3 duratec, just that O-ring. Link above shows photos.