I have a 93 F-150 with a 302 and AOD with about 110K miles. About 3 months ago I changed out the water pump because it was leaking out the little holes on the side. The temp gauage normaly would be on the R on normal. When the water pump went out the temp got up to the L but never reached the red. After changing the water pump the temp guage world read N on normal.

Everything was fine up to this past weekend. I pulled a trailer with 4-wheelers up to the deer camp, about 75 miles. That morning being cool the temp stayed on the n as normal. That evening comming home when it was hot the temp guage got up to A on normal and stayed. We stopped at a store to get some drinks and when I came out the water was bubbling into the resevor and out onto the ground.

When I changed the water pump I only put a little antifreeze in, maybe 1/2 gallon and rest with water just to see if it was going to leak. I never got around to flushing it out.

My question is why did the water bubble out into the resevor when the temp only got up the the A in normal? Is it cause it was just water and not antifreeze? Should I change the thermostat and flush the system, and put antifreeze back in? Could it be the fan clutch?

The reason I ask about the fan clutch is cause when stopped at a red light the ac gets warm. I know with cars with electric fans when this happens its normaly the fan out. Is it the same with trucks?

Sorry for the long description, but I want everone to know the whole story to make a better judgment. You guys have came through in the past on other questions, and I know someone will again on this subject. Thank you for any suggestions.

 

I don't think it has anything to do with the water pump. Sounds like your thermostat is working correctly. When cold, you should be able to turn the fan and the clutch will slip. When hot, it should be tight.

Check the radiator for damage or obstructions in the cooling fins. While you there check the condenser as well. Did you put the fan shroud back on? Then replace the radiator cap, it is cheap and often overlooked. A proper mix of 50/50 will disipate heat better. Worse case is you are pumping air into the system via a leak...Intake gasket...head gasket...crack...etc.

 

Thanks Ovalholic for the info. I still have to ask why the water was bubbling back into the resevor when it got a little hot. Was it cause it was mostly water? Or did the thermostat get stuck closed? Thanks again!

 

If you only had a little antifreeze in the water and running a 195 thermostat you may have been causing the water to boil at the water pump because of the pressure drop across the pump. The correct amount of antifreeze should raise the boiling point of water from 212 to about 285 deg. F.

 

Did you put the steel plate on the back of the new water pump when you replaced it. It will act really silly if you didn't. Did you replaced the thermostat when you changed pumps that is by far the easiest time to change a 302 thermostat. Rforse is correct if you have very little antifreeze in the system the boiling point is going to be real close to 212 or lower at higher altitudes. And whe you shutdown a motor the coolant always get warmer before it cools off so it indeed boiled over. Thus the water in the overflow tank. Bad clutch fan will only show up if you are running under 30-35 mph anything above that and you don't even need a fan.

 

Pure water will give much better performance in your cooling system then antifreeze/coolant. The point of the coolant (Ethylene Glycol) is to lower the freezing point and raise the boiling point. You lose a small portion of your heat-carrying capacity per volume of coolant fluid, but of course you don't boil off your coolant all the time either.

Sounds like you just need to empty and refill your radiator with a 50/50 mixture, or whatever mixture is applicable for your area.

 

Thanks Wtroger and Saurian for the info. Wtroger the new water pump came with the plate already on it so I put it back as it came off. I didnt change the thermostat at that time.

Last night I changed the thermostat and drained all the water. I filled it back up with 50/50. Then cranked the truck, but left the cap off. As the coolant level fell I kept adding more antifreeze. But it only held 1 gallon. As the coolant started comming out I put the cap pack on thinking the system was full. I let the truck get hot. Guage went all the way to the L on Normal. Also I was running the heater to see if it would get warm. It only blew cool air, never hot. Then I shut the truck off. After a few minutes I noticed the upper radiator hose was sucked flat. Tried to get the cap off but could not. So I pulled the heater core line and it sucked air into the system.

Replaced the hose, and put in another 1 1/2 gallons of antifreeze. Heater is even blowing hot again. Now everything seems to be working. I hope!

So is it safe to say the whole problem was that it didnt have any antifreeze just water? Thanks again. You guys came through again!

 

Sorry, one other quick question. If under normal driving the temp guage is reading between N and O on normal. If it gets up to say the L or anything past would that be too hot. I guess what i am asking is that the thermostat is rated at 195 degrees and that is the N in normal. If it got to the L wouldnt that be way too high of a temp? Thanks again

 

Just because your thermostat is 195 degree's does not mean the engine is at 195 degree's. Some engines run cool - my 300 has a 180 degree thermostat and it ALWAYS runs cool. It sounds like your truck does like to run a little hotter, which isn't a bad thing necessarily. As long as you have a quality oil and aren't getting TOO hot, you're ok. Going to the L isn't necessarily bad, I just wouldn't let it go any further, and wouldn't drive with it constantly on L.

You said the hose was sucked flat...you fixed that problem and now the temperature is back down again? The fact you weren't getting hot air says there was a blockage (the hose?) before the heater. I'm not really sure where you stand right now, but a sucked flat hose is a problem. One reason I'm going to go with dress up pipes - no more hoses and they look nicer =P.

For your own sense of security, I might recommend you take the truck to a shop (or do it yourself if you know where to put the reader) and get a true-temperature guage for yourself. That way you can find a baseline (What it reads when the truck is at or around N) and then you'll be able to know what that "L" is. Don't let it run hot for too long, that's when head gaskets like to pop, or the heads themselves like to open up - at least on smaller engines (GM 2.8/3.1/3.4, Ford 2.8/2.9).

 

Saurian, the hose didnt suck flat till a few minutes after I killed the truck. I dont think the heater was working and the temp went to L cause there was alot of air in the system. When I changed the thermostat I took my air hose and blew out all the water in the heater core, radiator, and engine block. The temp guage would stay dead center when I first got the truck. Then after it got hot and I changed the water pump the temp and Oil pressure guage runs on the N now. Thanks again Saurian.

 

Rkersh409, am I reading correctly that you filled the system, turned the engine over, added coolent, put the cap on, and then let it get hot?

If so, you need to let it get hot, turn the heater on, make sure the coolent is flowing, make sure you have heat, then put the cap on, and then make sure it maintains temp. Sorry if I didn't read that correctly.

The hose is flat because of air. Either it is trapped in the system or it is being pushed in.

When you replaced the theromstat you put the spring towards the engine hopefully.

 

Given the description at the FIRST post - YES it could be the fan clutch. I had all new parts in my 88 F150 5.0 and it would only run hot with the AC on in stop and go traffic. Never had a problem until I moved down south and the temp was 114 degrees!

Every time I shut it off it would boil the water out, always running right around the L.

New fan clutch and it won't come any higher than the N now. Best way to know if the fan clutch is good is that it should ROAR when you take off from a dead stop. Mine never roared since I got it, put on new heavy duty fan clutch and it roars now!

 

Thanks Ovalholic and Steven@nd. That is correct Ovalholic. That is the procedures I followed when I changed the thermostat. And yes the spring is facing the motor. I am pretty sure the hose went flat because of air in the system. After I removed the hose to open it back up. I had to add another 1 1/2 gallons of coolant.

Steven@nd, your right down here in Texas it was around 95 that weekend and I was pulling a loaded down trailer up and down some small hills and through some small towns that had a hand full of red lights. Also in Drive (not overdrive, around 3000 rpm's). That is when I noticed it getting up on the temp guage. I dont hear a roar your talking about. The only thing I hear is like rubber slipping. Maybe the fan clutch? When the truck is good and hot and I kill the truck. I am able to spin the fan by hand with very little resistance. I have never checked a good one to know how much is right.

But thanks again guys, sounds like I am going to go ahead and replace the clutch just to be on the safe side.

 

Quick test for a bad fan clutch is with the engine running use a piece of heater hose and see if by pushing the hose into the fan (watch the fingers) if you can stop it it's bad. It turning easy by hand is a good indication it's gone south. If you can see the shaft where it goes into the clutch and it appears to be oily it's bad.

 

It air locked on you. I have seen that before. Anymore when I do a water pump etc I leave the heater hose off until I see coolant come out. The small bocks seem to be real bad about this anymore.