I had a previous thread where I discussed getting the fan clutch replaced three times before the mechanic determined it was a head gasket leak. I don't think it is (Or I might just be in denial) I just don't trust them anymore.

I have a 2001 Ford Ranger, 3.0L V6 with 200,000 miles.

The problem is it overheats when stopped (sometimes, very random)

So, it has no symtoms of a head gasket leak(except overheating). Oil looks great and no white smoke coming from the exhaust. It overheats quite frequently, so you think there would be some symptoms... Right?

The heat doesn't work, so I assume I have a blocked heater core, could this cause any issues with the overheating?

It has a relatively new radiator cap, but I'm going to replace it anyways. It's also a new radiator and thermostat.

It has plenty of coolant and I don't see any leaks.

Maybe the pump is failing? Will it work sometimes and fail sometimes? And how can I test it when it is failing?

My head hurts, I don't know what to do...

An engine doesn't necessarily have to use coolant or contaminate the coolant with oil in order to have a blown head gasket or cracked/warped head. My '00 had an electric radiator fan malfunction and I overheated it badly, and now it overheats in normal use but doesn't use coolant and my oil isn't contaminated. Because I overheated it, and because Ranger 3.0's are known for blowing head gaskets, I'm almost positive that my engine has a blown head gasket or a warped/cracked head.

Doing a compression test and running a coolant gas test are two of the more common ways to test for a blown head gasket.

http://blockchek.com/

My friends Ranger does the same thing. We did the t-stat, nothing. Then we did the radiator since it was packed full of clay and mud, nothing. Then we pulled the water pump and the impeller was just gone. Replaced that and the truck stopped overheating. Try doing the pump. It's stupid easy on a 3.0

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2007 Regular Cab - 2.3 DOHC - 5 Speed Auto - 4.10 Gears - Maxtrac 7" Lift - Fiberwerx 3" Fenders - Bilstein 5100 Series - 15x10 Ultra 164's - 35x12.50x15 Red Letters - Custom dents

Well, people who neglect to change antifreeze encourage corrosion in the cooling system. This can result in....plugged heater cores and corrosion of the impeller on the water pump. Pull the pump and have a look, guessing is just that and doesn't deliver confirmation.

*You say the heat doesn't work, I assume you personally have checked to see if coolant is in fact flowing through the heater core Feel and compare the hose temps and verify that the coolant flow valve is open). And yes, there is a coolant gas test that can be done and I believe it's cheap. The question would be, is your coolant so new that the test would be a pass, if in fact there was a cracked head/gasket issue.

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2004 Ranger FX4 Level II, 5R55E, Sonic Blue Pearl

Proudly JAP/RICE free since March 2000

It sure wasn't stupid easy on my '00 3.0. :-(

Edit - oops! I'm thinking of the T-stat

Was a bit more time consuming than mine, but we didn't punch walls or invent new swear words.

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2007 Regular Cab - 2.3 DOHC - 5 Speed Auto - 4.10 Gears - Maxtrac 7" Lift - Fiberwerx 3" Fenders - Bilstein 5100 Series - 15x10 Ultra 164's - 35x12.50x15 Red Letters - Custom dents

are you sure you have enough antifreeze in it. the low heater core temp indicates either a bad water pump or low fluid level.

I see, dang. So there is for sure a chance that its a blown head gasket or cracked/warped head. I really hope it's not. Thanks for sharing.

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This would be a lot better than a head gasket leak! I'm going to have to pull the pump and see if it's messed up. The coolant when we got the truck had a lot of dirt in it (Georgia clay), so it is very likely that the impeller is messed up.

I'm going to watch some videos to see how hard it will be.

Thanks for the advice, fingers crossed its the pump and I can fix this overheating problem.

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The heater core hoses are pretty cool, both about the same temp, no coolant is flowing at all. The valve is open too.

I flushed the system not long ago, so it might be a little fresh. But, I think it's still worth a go. Thanks for suggesting it.

Nope, not for sure. You didn't mention in your original post that your coolant had a bunch of dirt (are you sure that it wasn't rust?) in it when you bought the truck... that important bit of info would lead me to believe that your coolant system isn't functioning properly.

The first thing that I would do is pull your water pump and see what the impellers look like. If they're worn or eaten away, then that's likely your problem. If they're not worn, if your heater core is plugged it wouldn't surprise if your radiator is also at least partially plugged, which would of course cause your truck to run hot. If it is plugged and flushing doesn't unplug it, you'll have to replace it.

Actually, yeah, it could quite easily be rust, it had an orange color like rust. I guess I just assumed it was dirt because thats what it looked like on the radiator cap.

The radiator is new. Thats also some important info that I missed out.

I would say that having a peek-see at your water pump impeller would be the next logical move.

If your heater hoses are cool and you have no heater you could very well have a large air bubble. There are 2 very small hoses on top of the intake plenum for heating the throttle body. I would remove one and try adding more coolant. Since that is the highest point in the cooling system it should allow you to bleed the air out.

Iv'e been watching videos on how to replace the water pump, It looks quite tricky. Do you have any suggestions on making my life easier if I replace the pump myself? The fan has been removed recently, so that should be easy to remove now.

I just don't want to mess anything up, I'm nervous to take the truck apart.

Let me ask a dumb question: what makes you think your engine is overheating? Are you basing this on the temp gauge or something else? A random temp gauge spike only at idle is not a true sign of a water pump impeller failure. It's been my experience when a impeller fails, the coolant temp never drops and certainly heat spikes are not random.

Before pulling the water pump, I'd first verify this isn't a bad coolant temp sensor. If that checks out I'd be sure to purge the cooling system of any air as Bob V suggested. Then I'd test the coolant for exhaust gas. Once you eliminate the easy/ small stuff move on to the big stuff like pulling the water pump.

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2000 XLT 4WD 4.0L OHV, 5 spd, Alabama Cylinder heads, Delta Cams Valve Train and Pushrods, JBA Headers, KKM Cone Air Cleaner, BBK Throttle body, Dynomax Cat-Back exhaust, Summit Racing drilled front rotors w/ EBC pads, Cobra rear disk brake conversion w/ Hawk pads, 8.8" 4.10 Traction-Lok

Just out of curiosity where are you located Rudy?

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Black 2008 ranger sport 4.0 SOHC SAS'd and converted to 4x4 riding on a Dana 50 up front and a sterling 10.50 in the rear regeared with 5.13's, mickey thompson classic 3's rapped in 37x12.50 maxxis creepy crawlers