Coolant Issues

[firebane]

Ok so a bit of the backstory. Rebuilt the top end of the truck over the winter and got it running and immediately noticed that when I run and shut it off I can hear what sounds like coolant leaving the heater core. When the truck has cooled off I take a look at the radiator and notice the cooland is down signifigantly.

Here is what I have done and noticed...

1) Thermostat replaced once with a 185 and noticed after I pulled it today it was faulty and replaced with a 195 that tested good in a pot of boiling water.

2) Heat blows damn hot in the truck

3) Top radiator hose gets hot

4) When the top is hot the bottom is usually cold

5) If I let the truck sit the bottom hose will get warm and the rad cap will get hot.

6) Radiator is brand new

7) No white smoke out the tail pipe nor any sweet smell

The only thing I have left to try is changing out my water pump as I have no idea the age of the one in the truck. People say you can tell if your water pump works by watching the cooland in the radiator and it should be pouring back into the radiator which I don't see this happen. But I have also heard this can be a bad thermostat but the top hose gets hot so that means fluid is getting back to the radiator.

Could I perhaps have a bad water pump casing all this? I am really really hoping that its not a bad head gasket somewhere but with as much coolant as I'm losing I would think it would show up in the exhaust or somewhere.

Does the top of the overflow bottle need to be sealed off? Mine doesn't have a cap on it but the hose sits in it.

 

[chengny]

How much coolant are you losing? Like in how many quarts do you have to add per week?

People say you can tell if your water pump works by watching the cooland in the radiator and it should be pouring back into the radiator which I don't see this happen.

This only works as long as the coolant in the outlet tank is below the level of the upper most row of cross-tubes.

Also the engine must be fully warmed up (at least hot enough for the t-stat to be well open and allowing a good flow into the radiator's inlet tank).

When the engine is good and warm and the coolant level is...say at least 4 inches down (low enough that it can be seen flowing out of the ends of the cross-tubes into the outlet tank) - reach over to the carburetor and grab the throttle linkage. Then, while looking down into the outlet tank, rev the engine a bit. Not too much. Two times normal idle is fine - no need for a tach, just do it by ear.

As the engine rpm increases, so does the speed of the water pump. Coolant flow increases with the increased speed of the pump. The suction side of the pump is piped to the bottom of the outlet tank.

The water pump now begins pulling a greater volume of coolant from the outlet tank and the level falls - even lower than where you dropped it to at the beginning of the test.

This is because of the piping restrictions of the radiator cross-tubes. The pump is removing coolant from the outlet tank at a faster rate than the cross-tubes are able to deliver into it from the inlet tank.

While the water pump has the level down low, you should be able to easily see dozens of little streams of coolant pouring out of the cross-tube ends and dumping into the outlet tank.

If you release the accelerator linkage and let the engine fall back to idle speed, the level in the outlet tank will immediately rise back to where it was when you started.

If you play with the engine RPM for a while and see that the level rises/falls in quick response to decreases/increases in engine speed - you have will have verified that your water pump is in good shape and working as designed.

 

[firebane]

This isn't per week this is per startup.

I top it off put the cap back on let it run for a bit then when I shut it off in an hear the coolant rushing.

Once the truck is cool enough to open the cap if I look inside the radiator the coolamt is almost down to where the upper line for transmission connects.

I can them repeat this process and it's always the same amount of coolant lost.

This completely baffles me.

Regarding water pump what if I don't see any streams? I would assume pump is not working as it should? Since the lower rad hose is always cold when the upper is hot? And the lower as well as the rad cap doesn't get hot until I shut off the truck?

 

[mistaake]

I don't think the water pump would cause it to lose/consume coolant, just not pump it. Your coolant could go a few places:
-an external leak, but you'd probably notice if you left the truck running for a few mins and found it on the ground
-into the oil. should be obvious on the dipstick though. in this case, probably head gasket issue
-into the combustion chamber. should be obvious by white smoke out the tailpipe. in this case, probably head gasket issue
-into the transmission cooler lines, if your radiator has a built in transmission cooler. but you would notice problems with your transmission before you noticed problems with the coolant level

 

[firebane]

I don't think the water pump would cause it to lose/consume coolant, just not pump it. Your coolant could go a few places:
-an external leak, but you'd probably notice if you left the truck running for a few mins and found it on the ground
-into the oil. should be obvious on the dipstick though. in this case, probably head gasket issue
-into the combustion chamber. should be obvious by white smoke out the tailpipe. in this case, probably head gasket issue
-into the transmission cooler lines, if your radiator has a built in transmission cooler. but you would notice problems with your transmission before you noticed problems with the coolant level

Exactly. And none of this is showing ANY symptoms. Its not my first rodeo with coolant and finding out what is going on but this is absolutely baffling.

See here is my thought. When I start the truck it pulls fluid into it through vacuum and then the pump doesn't have enough oomph to push anymore. So when I shut the truck down the fluid is warm enough so that it ends up in the radiator which causes the lower hose and cap to be warm.

I'm going to replace the radiator cap tonight to see if that makes any difference and if doesn't then I'm going to be replacing the water pump.

 

[MadOgre]

Exactly. And none of this is showing ANY symptoms. Its not my first rodeo with coolant and finding out what is going on but this is absolutely baffling.

See here is my thought. When I start the truck it pulls fluid into it through vacuum and then the pump doesn't have enough oomph to push anymore. So when I shut the truck down the fluid is warm enough so that it ends up in the radiator which causes the lower hose and cap to be warm.

I'm going to replace the radiator cap tonight to see if that makes any difference and if doesn't then I'm going to be replacing the water pump.

First off go down to parts source or Canadian tire and buy a fail safe thermostat. it costa like $2 more. I have had brand new ones fail instantly. The fail safes work for years and only had one fail but it failed open like its supposed to.

The other idea would be to run it with out a thermostat to be able to rule out the thermostat. If it still does it then I would disconnect both input and out put hoses and pour coolant in the top until it pours out the bottom. Then refill everything. as it sounds like maybe an air lock.

Water pumps are cheap so just replace it if there is any doubt

 

[firebane]

First off go down to parts source or Canadian tire and buy a fail safe thermostat. it costa like $2 more. I have had brand new ones fail instantly. The fail safes work for years and only had one fail but it failed open like its supposed to.

The other idea would be to run it with out a thermostat to be able to rule out the thermostat. If it still does it then I would disconnect both input and out put hoses and pour coolant in the top until it pours out the bottom. Then refill everything. as it sounds like maybe an air lock.

Water pumps are cheap so just replace it if there is any doubt

I picked up a Napa Premium 195 and tested in water to ensure it opened and closed and being that the upper hose gets hot would that not mean fluid is flowing throw the upper rad hose?

 

[DoubleDingo]

That is very odd. You would think the system would be out of air bubbles with all the times you've topped it off. And there should be a distinct smell if it's being leaked out. How does the oil look? Is it milky in appearance?

When I evacuated all the coolant from my engine I took a small diamter funnel and added coolant through the heater hose hole in the intake until it was full, and then filled the radiator. It was basically full at that point and needed very little to top it off. The top hose will be hot even if there isn't water going through. Steam is hotter than boiling water so the hose will feel hot.

 

[MadOgre]

You would think.

Don't go to napa they are rip offs. They sell the same water pump as Canadian tire but for $60 more.

The fail safes always fails open vs Napa's high end that will still fail closed.

Like I say probably a air lock or the pump and the pump is $35 at Canadian tire so either way youll get it done !

 

[PrairieDrifter]

The upper radiator hose gets hot only when the thermostat opens, have you checked the water pump weep hole to see if it's leaking?

It sounds like there's a lot of air in the system or getting into it somehow, do you just pour coolant into the radiator or do you have one of those radiator funnels with the adapters? Those special funnels work good for getting a lot of air out, better than just pouring it in or using a normal funnel.

 

[MadOgre]

If you just run it for like an hour with the cap off most if not all the bubbles will work its self out

 

[firebane]

That is very odd. You would think the system would be out of air bubbles with all the times you've topped it off. And there should be a distinct smell if it's being leaked out. How does the oil look? Is it milky in appearance?

When I evacuated all the coolant from my engine I took a small diamter funnel and added coolant through the heater hose hole in the intake until it was full, and then filled the radiator. It was basically full at that point and needed very little to top it off. The top hose will be hot even if there isn't water going through. Steam is hotter than boiling water so the hose will feel hot.

Hmm I suppose. But you would think that heat inside the truck means the waterpump IS working unless the waterpump is JUST pushing enough through the system to keep it warm.

You would think.

Don't go to napa they are rip offs. They sell the same water pump as Canadian tire but for $60 more.

The fail safes always fails open vs Napa's high end that will still fail closed.

Like I say probably a air lock or the pump and the pump is $35 at Canadian tire so either way youll get it done !

Yeah I'm not sure why I didn't replace the water pump LOL. I mean its got a new rad and thermostat.

Could the radiator fan being on all the time be a hinderance too? I mean if its cooling too fast the water could never heat up and allow the thermostat to open properly?

 

[MadOgre]

Hmm I suppose. But you would think that heat inside the truck means the waterpump IS working unless the waterpump is JUST pushing enough through the system to keep it warm.



Yeah I'm not sure why I didn't replace the water pump LOL. I mean its got a new rad and thermostat.

Could the radiator fan being on all the time be a hinderance too? I mean if its cooling too fast the water could never heat up and allow the thermostat to open properly?

No I don't think so. It will just never warm up all the way. It will run better with a fan clutch but I don't think that's the issue.

 

[DoubleDingo]

I have run them with a constant running fan in the dead of winter and the engine got plenty warm, just need the 195 thermostat.

 

[firebane]

You know you always hear those "stories" about people overcooling their vehicles and think to yourself nah ... no way!!! Dudes full of crap.

Let me tell you I can't be a naysayer anymore!!!!!

So I went to Canadian Tire and picked up a infrared thermometer because I was simply curious of what the temps were of things when they were running. The truck gets up to temp and I check the temp at the water pump where its entering the block...

180* F

So then I put the gun on the base of the waterneck..

170* F

I am showing a 10 degree difference between the water neck and the water pump... So I check the temp of the radiator ... 41* F. Hmmmm I go this can't be right can it?

So go into the shop grab a couple of tools and pull the fan off the truck and run straight pulley no fan. Start the truck again and let get running and now I put my gun on the water pump at the head again..

190* F

I jumped 10 degrees by removing the fan!! I'm thinking hmm really? So I let the truck run some more and then I check the pump at the head..

205* F

Well now I'm shocked! So I put the gun at the base of the water neck..

195* F

Look into the radiator and the coolant is bubbling and I can actually see the coolant flowing like its supposed!!! Succcesss!! Water pump is pumping.. thermostat is opening.

So guys.... Yes you can simply overcool your vehicle based off the fan you are running!!!

So this weekend off to PnP to pick up a clutch fan.