So here is what I'm trying to figure out. The engine i just put in runs fine...however I seem to have a serious glitch somewhere in the cooling system of the engine. What is happening is the water in the radiator is starting to boil. However, it doesn't look like waters is even flowing through the radiator. When the cap is removed and you look in while running the coolant just sits there. Then when i go to turn it off its like a volcano of anti-freeze.

So I pulled off the water pump and i'm about to go and see if i can get water to flow through the heads and block and through the water pump. My question is if anyone has encountered this problem before what was the problem? Thanks for the help.

Tristan H.

You may have a thermstat problem but why didn't you do a more thorough diagnosis before yanking the water pump?

As Mrapii said,

It sounds to me like your theromstat isn't opening. Buy a new one and throw it it. It's pretty much impossible to tell by looking at them, Most of the time when they have failed, they look like the would work perfect, and you can move them with your fingers, but they don't open and allow the coolant to flow in the rad.

Install the new pump. If the problem still exists, check out the thermostat, radiator, thermostatic fan clutch and radiator shroud including how far into the shroud the fan extends and the clearance between the tips of the fan blades and shroud.

I'm having a similar problem, I already tested my thermostat (put it in near boiling water), it's fine. So I'm looking towards the water pump, I tried testing it by pinching the hose by couldn't really tell. Anyone know a better way to test the water pump? I mean they are cheap enough that replacing them is no huge deal, but I'm a bit strapped for cash right now.

What's your rough coolant/water mix?
have you touched your timing?
what about your fan system? mechanical or electric?
fan shroud clearance?

In my experience, water pumps have to be replaced because the shaft seal goes bad and it leaks coolant, not because it stops pumping. However, many years ago, I saw one where the impeller appeared to have eroded away, but I consider that very, very rare. At any rate, if it is not leaking, the pump is the last component I suspect when a heating problem is encountered. Check out the other suggestions mentioned in the earlier posts because the problem is much more likley to be one of them.

If the pump Is new, you may have what happened to me ----somehow a water pump got switched in the box in a parts house and I was given a normal rotation pump instead of a reverse rotation pump for my pickup. The darn thing would go all the way to hot before the thermostat would open, then it would go completely cold and shut off and go through this cycle several more times before it settled down-----since I was not the regular driver of this truck it took a few days for this to be communicated to me and the water pump replaced with the correct on----now the engine smokes a bit on startup and exhibits other wear symptoms that were not there before the pump was replaced----so my advise is find it as soon as possible before you "burn" the engine up................Dan

I will say that you can get bad "New" or "Re-built" parts from a parts house. It happens every day. But since you haven't purchased one yet, I'd let it run until it heats up to normal operating temp.

Shut off the motor, put your hands on the radiator, feel the temps from left to right. It should go from very hot to cooler but not cold on the right hand side or Passenger side. There should be a difference in temps about 20 or so degrees, left to right or driver side to passenger side.

If there is a cold spot that is unusually cool or cold then you have an obstruction in the radiator. More than likely it is sludge and silt built up from years of use or someone at one time or another put some Bargs leak or stop leak in it and that had congealed in the bottom finally. I would never suggest that as a fix unless you so damn far away from a place that is the only option!

Your fan should be, not flex type, spinning where you can feel the air with force blowing over the motor as it runs. The shroud should be in good condition and completely against the back side of the radiator with no gaps and no bug holes in the shroud. You can check the clutch by spinning the fan with the engine off of course. If it spins with no force then replace the clutch its bad. If it will not spin at all replace the clutch its bad. There should be some force to it but not a lot of force to it.

If the shroud is in good condition, the fan clutch is in good condition and your not using a flex fan, then remove the thermostat, put it in some boiling water, if it opens up it is "at least working" maybe not like it was suppose to but working. You can check the opening temps with a temperature probe from your kitchen. Meat thermometer its close enough.

If the thermostat is opening at or close to 180 / 190 then flush out the block with a good high quality Flush. If the radiator is cold in spots when you feel it then replace the radiator. Its just not worth it to have it rodded and cored. It would cost pretty close to the same as buying a new one. I got a new HD radiator for under 100.00, three row.

If none of that fixes the problem then you have a timing issue that should be fixed ASAP. I'm with the one that said don't run the truck while it is over heating.

By the way........ Does it over heat on the freeway at 55 or 65? If it does then I'd say its the radiator, but even that is a guess at this point.

http://elcaminoplace.com/technotes.html

Check out the third article down the page. Its all about the cooling system and how that all operates and what have you.

Good Luck

I agree with Elkypete about replacing the radiator instead of rodding or cleaning it. The last time I had one rodded, it cost me $70.00 and within a year the top tank was leaking. That was the last time I will do that. Another $30 bucks for a new radiator would have been the smart thing to do.

Hello: Overheating can be caused by lots of things, but lets start with some basics. At sea level water boils at 212 degrees, if you live higher than sea level it will boil sooner, say 200, 190 or something like that. Never remove your radiator cap while the engine is running or after you shut it off, unless you have a big rag over the cap to keep the water that will be above 212 from gushing out all over you. There is a cap on your radiator, not to keep the fluid in so much as to keep the pressure in. If the cap is working properly it will allow your engine to get hotter than 212 degrees without boiling the water out. What happens in a good working system that has say a 190 degree thermostat or so, when you turn the engine off the water actually gets hotter, possibly past 212 degrees (there is no radiator cooling when the motor is not running, no fan) If you open the radiator cap and temp is above 212, the water will instantly boil and blow your face off. Just about all the water in the engine will come out through the radiator cap in a second or so. Be careful when working on an overheating engine.

Next , when you start a cold motor the water will do nothing but sit there, it will not appear to be flowing (the thermostat is closed). If the thermostat is 180 degrees the engine may reach 200 before the thermostat has time to react and open fully, then the water should be at the thermostat setting.

The other thing that heats water up real fast is a blown head gasket into the water jacket. You can sort of test this by running a hose into the radiator cap opening and keeping the radiator absolutely full all the time. If you see bubbles always coming out of the radiator try to smell the air when they break open to see if they smell like exhaust fumes, or is smoke pops out of them. There should be NO bubbles in the cooling system at all.

Check your timing to be sure that the timing is within specs, if you have an adjustable light make sure it is set to O degrees for initial timing checks.

Water pumps usually always leak when bad ormake noise, but still pump water. I have seen some with plastic impellers break and not rotate due to the water drag, but thats been very few and far between.

To test the radiator remove both hoses and the cap. hold your hand over the lower radiator opening. Fill the radiator with water. Remove hand. Radiator should empty in a few seconds. If blocked or plugged water will drain much more slowly.

Make sure the fan is rotating, make sure the fan shroud is on, make sure there is a good operating thermostat in the engine. Sometimes removing the thermostat will cause the engine to run hotter because the water does not stay in the radiator long enough to really cool down any.

Try those things. Good thermostat, good pressure cap on the radiator, radiator clean and free of bugs and dragon flys, no blown head gasket
good luck
darryl..