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Well onto the next item to fix...what appears to be a head gasket problem :(.  I'm extremely certain that my issue is in fact a bad H.G. but I took a short video so you all can see what I see.  The video was taken right after shutdown on a hot engine.  What caught my attention, initially, was the upper radiator hose becoming quite firm upon squeezing it at operating temperature.  For what it's worth, I had gotten some air into the system (changed the thermostat and radiator cap/went on a short drive up to operating temperature).  I cant imagine these bubbles have anything to do with air being bled out on its' own?  I did park the truck nose up and burped the system the best I could prior to my short trip.  I pulled over when I saw the dash reading 190 and looked into the overflow tank and didn't see any bubbles?  Maybe I didn't look long enough?      

 

I've had coolant loss during my ownership of this vehicle (onto year 5 now).  I flushed the system back in 2015 and my overflow tank went from the full mark to the add mark in these five years.  I don't have any details other than that because that's all I can remember.  For example, I cannot pin point a certain date when I noticed a significant loss of coolant.  I discovered, in 2020, I had a leaking heater core which I replaced earlier this year (not sure how long that was leaking).  Perhaps that had something to do with it as well.

 

At the current moment:

  • Truck does not overheat
  • Thermostat is opening and closing
  • Oil level is normal on the dipstick
  • Radiator and oil caps showed no signs of contamination when changing coolant (Spring 2020)
  • No visible antifreeze leaks
  • Can't see any white smoke out of the tailpipe

 

I have not been driving the truck very much because I don't want to make the problem much worse or get stranded.  With that, I can't say unequivocally if the truck has been (lately) using coolant or not.   

 

My biggest concerns now are the upper radiator hose being very firm and these bubbles which I now discovered.  I can't tell if the lower hose is firm as well because of the spring inside of it. 

 

I'm at 156.5K miles on the vehicle.     

 

Thanks All!

 

         

 

 

 

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How does the oil look? Like oil or milky? When mine failed it was leaking outside the head and never got in the oil. But I could see the wet spot on the head/block junction right near the tstat housing. 

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Coolant system will be pressurized to whatever psi it says on the cap...  and 190 is ok if you have a 190 thermostat

 

What is not ok is if the 2 conditions happen very fast..... ok if within normal warm up time

 

Full to add in 5 years is ok... full to add in 5 days is a leak

 

Can you borrow a coolant system pressure tester or a gas tester ? Gas tester checks for combustion gas in coolant system

 

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6 hours ago, sooxies said:

My biggest concerns now are the upper radiator hose being very firm

 

You may have a valid concern..., or not.  You didn't mention what the conditions were when you noticed the radiator hose was firm.

 

Normal cooling system operation with a 15 psi cap and an overflow container and an engine that has been shut off for at least overnight works like this:

 

*  Before engine is started the radiator will be 100% full and the overflow container will be less than half full (coolant will have be drawn into the radiator from the overflow container during the night from a cooling engine.  A one-way check inside the radiator cap accomplishes this task.)

*  As soon as the engine is started, pressure will start building as the coolant temperature rises with a closed thermostat.  It won't be long before the pressure reaches 15 psi and some coolant is transferred to the overflow container.  If you checked the firmness of the radiator hose at this time, you will find it very firm.  This would be normal.

*  As you start driving the truck, additional fueling generates more heat and more coolant is transferred to the overflow container.  After driving a while, a balance will occur as the thermostat adjusts to the rate the engine is heating and the radiator is cooling.  At this time coolant stops being transferred to the overflow container because the coolant pressure is no longer rising.

*  As soon as you reduce the engine load (such as pulling off of the freeway and parking the truck) the coolant pressure drops considerably - down to as low as 2 or 3 psi.  At this time with the engine still running the radiator hose should not be firm.  If it is very firm, I would be concerned.  (In the old days when trucks had top tank radiators and no overflow containers, this was the time to check coolant level on a warm engine).  The next morning before the engine is started, the radiator should be 100% full and the coolant level in the overflow container should have dropped some.

 

So, I would start from scratch and the first thing I would do is make sure that the radiator is 100% full and the overflow container at least 1/3 full before starting the truck after it set overnight.  Then I would drive the truck and work the engine a bit and bring it home and before shutting the engine off, I would check the over flow container and the firmness of the radiator hose.  If the hose is very firm, that could indicate that combustion gases are entering and pressurizing the cooling system.  After several hours and before starting the engine again, I would check the coolant level in the radiator.  It should be filled to the brim.  If it is not, then again, this could be caused by combustion gases entering the cooling system.

 

I would repeat this procedure everyday for at three days or so to get rid of the possibility of trapped air in the cooling system.  A radiator pressure tester would be useful to find leaks and also to prove the radiator cap is relieving at the proper pressure and the cap doesn't leak.

 

- John

 

 

 

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Soox,

 

TL:DR  at bottom

Think of it like this.   When you start a cold engine,  there is lets say 6 gallons (notice the measurement is a volume) of coolant in the system.  All of this coolant is 60 degrees F.   When it gets to 190 degrees F, it is 6.25 gallons of coolant. (the mass of coolant stayed the same but the volume increased.)

 

If our coolant system was just open to the atmosphere, you would push out the 1/4 gallon.  Our system has a pressure cap.  So the expansion of fluid is allowed to pressurize to a pressure, THEN it will allow some to spill to the reservoir. 

 

One thing to keep in mind, while the water temperature may be 190F,  most of the surfaces inside the engine of the cooling system are much hotter than that.  In fact many of the surfaces the coolant is touching are WAY above the boiling point of the coolant (if you are 50/50 it is about 225F with no pressure).  The coolant in touch with a surface that has a temperature higher than 225F IMMEDIATELY BOILS, but then cools down quickly.  This boiling will cause small bubbles in the coolant.  This is bad, but unavoidable, for many reasons.  The bubbles do not transfer heat well.  the bubbles lead to cavitation in the pump etc.  While the engine manufacturer cannot avoid the sudden bubble formation, through good design, they minimize the effects.  High turbulent flow keeps the insulating bubbles from staying on the surface.  turbulent flow causes the hot gas to cool and collapse, reforming into a liquid.  

 

A hot engine, turned off will form bubbles out the behind.  There is now no flow to break them up and move them.  (pop your belt off and run the water pump with a drill, bubble formation will be minimized.)

 

To look at this at home, grab a pot and put some water in it.  Throw it on the stove.  Crank the stove eye to high.  Watch the water.  The very first thing you will see is the formation of bubble on the bottom surface.  now stick your finger in the water (or stick a thermometer in it for weenies), is it boiling?  no, its not close, but the water near the bottom of the pot is boiling, but the whole mass is not near boiling.  now start stirring the water, are there more or less bubbles?    Now as the whole mass of water begins to get hotter, more bubbles will form.  Until we hit the point where it is at a "rolling boil".

 

The "hard upper radiator hose is a head gasket leak" has a HUGE caveat.  The engine must be cold.  The hard hose should be noticed in the first less than a minute of running.  (so basically that there is no way that expanding coolant can create the pressure.)   As many head gaskets (and cracked heads) as I have replaced, I can only think of one case where you may have noticed a hard hose during cranking...  but the other signs were still huge and more obvious.  

 

When they catch the bubbles in a cooling system shooting for a head or head gasket diagnosis, they capture the expanding gas and test it for byproducts of combustion, (probably carbon monoxide, or carbon dioxide)  otherwise they couldn't tell the difference between natural formation of bubbles from head/head gasket problems.

 

Now when our cooling system cools down,  If the radiator cap operates properly, the coolant goes from 6.25 gallons back to 6 gallons.  This cooling creates a negative pressure, and "sucks" the coolant back from the coolant reservoir back into the radiator.  ( ambient air pressure is greater than the pressure in the coolant system due to the reducing volume, and the coolant is pushed back in....)

 

TL:DR  probably nothing wrong.  but keep an eye on it.

HTH

 

Hag

 

 

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Posted (edited)

@dripley Oil looks great!  Nice and golden.  The level on the dipstick has not risen at all.   

@wil440 Yes...running a 190 thermostat.  I will pressure test to be certain.

 

@Tractorman  @Haggar Thank you for the explanation!  I originally was running the 19 PSI cap that came with the Mishimito radiator but have now switched back to a 16 PSI to see if that had any effect.  I let the truck idle for about a minute in the driveway (before going on my test drive) and the upper hose didn't dramatically become firm.  Again, I don't know how firm is too firm at operating temperature.  It's a pressurized system yes, but how much is normal?  It's starting to rub ever so slightly on the black cover that surrounds the APPS sensor.  Is it just an old hose?     

 

This morning I checked the overflow tank and it went down about a quarter of an inch or so.  Upper hose was pliable and "limp" I'd guess you say.  I'll do another drive later today.

 

Thank You all!      

 

Edited by sooxies
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26 minutes ago, sooxies said:

It's starting to rub ever so slightly on the black cover that surrounds the APPS sensor.  Is it just an old hose?     

Every upper hose I have put mine needed some trimming where it fits on the radiator to be sure does not rub. 

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Posted (edited)

Soox,

 

Too firm and almost firm  etc etc are too subjective of statements.  The reason the cap has a pressure setting is, its allowed to rise to that pressure and then be relieved, maintaining at or below that pressure.  When we come to the hose, in theory you could determine the internal pressure by a deflection game on the exterior of the hose, but that information is not easily available, and would be different for each batch of hoses made... (what is the elastic properties of the reinforcing cloth etc.) 

 

You can do this for yourself if you are really interested.  Get a pressure test rig for the radiator (this way you can put differing pressures in the system.)  get  a tool like a belt tension gauge that allows you to put the exact same amount of force repeatably.  Get a tool to measure the deflection. (or a good reference on the engine if the tool has built in measurement.)

 

Make a chart for deflection vs pressure.    Now anytime you wanted to know the pressure, you could measure the deflection with the know force and voila  you know the pressure.  

 

(or as you are using the pressure test rig, just feel your hose at different pressures.  you may remember the feeling of the different pressures)

 

The other thing, you could put a pressure gauge in.  For testing purposes, just hook the pressure test rig up,  and run the engine.  As the pressure rises you can read it on the gauge. 

 

How much pressure should it have?  (I can hear my friends in unison...  The perfect engineering answer....)  "Well, it depends."  

 

There are too many variables there is no way to know what it "should be".  Has so many things to do with things that are totally not controlled (or specifically controlled individually, but only generally controlled as a unit).    I bet if you watched the "operating pressure at a given coolant temp" of each vehicle as it left the assembly line, there could be as much as 10 psi difference.   Most would probably be in a 5 psi group, only by accident would they be the same.... (mainly because they all got the exact same coolant mixture, it came out of the same rail car.)  Slight difference in hose lengths, slight difference in fan blade angles, accidental blockages in radiator or other parts of cooling system.  routing of hoses (is the heat shield in exactly the right/same spots.) dimensional differences in water pumps...  the list is ENORMOUS.

 

Be happy with.

1. when cold, hose is not pressurized.

2. when just started, the hose shouldn't immediately become pressurized.

3. when hot, the hose is firmer than it was when it was cold.

4. no loss of coolant.

5. (nice when it works properly) full cold radiator, when warm increases the level in the coolant tank, and when cools back down, pulls coolant sent to the tank back into the radiator.

 

GL  HTH
 

Hag

 

Edited by Haggar
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dont forget that a pressurized system will have a higher boiling point so that it wont "boil over". so at 220F its hotter then hell but it wont boil over while sealed up to the pressure max of the radiator cap. the radiator cap keep the system from popping a hose or headgasket or other water gasket.

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On 6/24/2020 at 1:54 AM, Tractorman said:

 

 

*  As soon as you reduce the engine load (such as pulling off of the freeway and parking the truck) the coolant pressure drops considerably - down to as low as 2 or 3 psi.  At this time with the engine still running the radiator hose should not be firm.  If it is very firm, I would be concerned. 

 

 

 

What you stated above seems to be an issue for me.  Whenever I pull over to take a look under the hood (truck idling/at operating temp.) the hose is still firm.  Not a good sign I take it. 

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Posted (edited)
4 hours ago, sooxies said:

Whenever I pull over to take a look under the hood (truck idling/at operating temp.) the hose is still firm.  Not a good sign I take it.

 

Not necessarily.  If you are driving an empty truck around, the engine won't generate nearly as much heat as a loaded truck or a truck towing.  So in your case the hose would likely have a firmness to it.  As @Haggarpoints out, firmness is very suggestive and can be different for everybody.  I apologize for directing your focus on that point.  So, I would focus of something less suggestive, like monitoring the coolant level in the radiator and the overflow container for a few days and see if you can be confident that everything is either okay or at least narrow down the possibilities of what is going on.

 

One thing for sure - in a normally operating cooling system the radiator should always be full to the brim.  The pressure relief and the check valve that allows return flow inside the radiator cap ensure that the radiator will always be full.  There really is only one time that you can safely check the coolant level in the radiator and that is when the engine has been off for several hours.  And, when I say full, I mean that when you slowly remove the radiator cap in the morning before starting the engine, the coolant should flow or be ready to flow out of the opening.  If it is down a half inch or more, something is not right.  The following are some possible causes:

 

*  There is a small leak in the cooling system.  A small amount of coolant leaks out while the engine is running.   When the engine is shut off and the engine begins cooling and the pressure falls below atmospheric pressure, it is easier to draw air through the leak rather than lifting the coolant from the overflow container.

*  The radiator cap is dirty, faulty, not sealing, or just plain worn out - again drawing air into the cooling system as the engine cools down.

*  The small hose leading to the overflow container is cracked or not sealing which again allows air to be drawn back into the radiator while engine is cooling (a fairly common, but unobserved problem).

*  There are combustion gases flowing into the coolant while the engine is running.  This is the most serious situation.  As the combustion gases enter the cooling system the pressure will rise faster than normal.  The gases, being lighter than the coolant, will move to the top of the radiator.  When the pressure overcomes the radiator cap relief valve setting, the gases enter the overflow container along with some coolant.  Once the flow of the combustion gases entering the cooling system match the flow of gases entering the overflow container a  balance will have been achieved.  At this point the radiator cap is allowing a continuous flow of gases at relief pressure to enter the overflow container.   The engine will run fine and will probably not overheat.  After the engine is shut off and cools completely, coolant will NOT return to the radiator because at engine shut down the coolant pressure was at the cap relief setting and there are compressed gases in the uppermost part of the radiator.  After complete engine cooling the gases will decompress, but will still remain above atmospheric pressure, so no coolant returns to the radiator.

 

As you can see, there are a lot of possibilities.  I recommend that you start with the simple stuff in a methodical manner.   Don't jump to the worst case scenario.  A radiator and cap pressure tester is a very useful tool for finding leaks and for checking the condition of your radiator cap.  The tester can usually be loaned or rented from an auto parts store.

 

Keep us posted...

 

- John

 

 

 

Edited by Tractorman
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@Tractorman  Thank You very much sir.  I ordered a pressure test kit from Mityvac and it will arrive on Sunday.  Slowly building up a tool collection so I figured it's worthwhile to have around even if it will not get used very often.  I know they're self explanatory but I have never used one before.  I'm assuming if there was an external leak one would see bubbles and/or hear air hissing.  What about if there's an internal leak?  Will I be able to hear anything?  I think what I'm trying to say is: What is the process to rule in or out a bad head gasket using this tool.  :thumb1:

 

Thank You!

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While you are waiting for your pressure tester to arrive, go on-line and watch the 6 minute video below presented by Mityvac.  The video shows you how to use the tester and to diagnose cooling system problems, particularly the potential head gasket problem.

 

https://www.youtube.com/watch?v=cRoYbDDGHTk

 

- John

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I have the kit made with a plunger type air compressor and I have in some cases with pressurized over flow tank vehicles cut the heater hose and installed a copper fitting between the hoses  with a silver soldered schrader valve to test the system with air conditioning hoses. can set it in the window area and drive and watch the readings. Can pressurize at the schrader and look for leaks.

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On 6/24/2020 at 5:20 AM, wil440 said:

Can you borrow a coolant system pressure tester or a gas tester ? Gas tester checks for combustion gas in coolant system

 

Did you check for combustion gasses in coolant. 100% sure test.... if HG is leaking combustion gas into coolant the test kit will spot it, saves all the ...maybe... not sure..... and wasted time

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Be aware even when my head gasket failed there was no combustion gases in the coolant. Only the coolant leaking out the back of the head on the passenger side. It only randomly leaked too. The day I decided to change the gaskets and do the head job I ran the truck super hard, EGT passing 1,400*F, pulling 3,000 RPM , and came back to the shop and backed in the shop and there was ZERO coolant leaking. Now the night before it leaked a hamburger bun sized puddle on the garage floor.

 

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Posted (edited)

Ok all.  I did all the tests that are show in the video (they are the same as in the users manual for the tool).

 

Test 1: System held 16 PSI just fine (cold engine and not running) :thumb1:

  • Stopped test just under five minutes.  Needle did go down.  

Test 2: Needle did not immediately rise upon startup (cold engine) :thumb1:

  • Stopped test around 90 seconds.  Seemed normal.

Test 3:  Needle was not vibrating with system pressurized to 16 PSI but was very slowly starting to rise (engine running/cold motor) :shrug:

  •  Ran this test for about 90 seconds.  No needle vibrations but the gauge was slowly starting to rise while the engine was running.  I shut down the engine.  It reached around 17 PSI.  Now, the test adapters have a spring in them like a normal radiator cap does but I cannot find out what they are rated for.  Shall I do a retest?  How high would be too high if I am seeing the gauge rise with the system pressurized to 16 PSI engine running?      

 

I did hear a very faint bubbling/gurgling sound when I started test number 1.  Sounded like it was near the thermostat housing.  No leaks are seen.  Could there be air trapped in there? 

Edited by sooxies

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10 hours ago, sooxies said:

Test 1: System held 16 PSI just fine (cold engine and not running) :thumb1:

  • Stopped test just under five minutes.  Needle did go down. 

 

Could be normal.  The air that you pump in will rise in temperature slightly and cool off (contraction) while you wait  - the laws of physics.  How much did the needle drop?  Were you doing this in the evening while the ambient air was cooling?

 

10 hours ago, sooxies said:

Test 3:  Needle was not vibrating with system pressurized to 16 PSI but was very slowly starting to rise (engine running/cold motor)

 

Was the system already pressurized to 16 psi when you started the engine?  You mentioned that it rose to 17 psi in about 90 seconds.  I have never performed this particular test, but I would expect the pressure to continue to rise at a slow pace because the engine is generating heat. 

 

10 hours ago, sooxies said:

Test 2: Needle did not immediately rise upon startup (cold engine) :thumb1:

  • Stopped test around 90 seconds.  Seemed normal.

 

This test showed good results.  Overall, there is not a red flag saying that your head gasket is leaking combustion gases into the coolant. For your peace of mind though, you could do the combustion gas test kit for your coolant as @wil440suggested.  I have never used one, but idea is a good one.

 

- John

 

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Posted (edited)

I find it very hard to fully fill the coolant system on both dodges.

 

The upper radiator hose is higher than the top of the radiator.   I can usually squeeze the hose and suck a bit extra coolant in there, but I can't positively ensure all the air has escaped.  Even when I use my funnel with the extension and radiator adapter, I don't feel like I have gotten all the air out.  Part of me wants to make a bleeder in the upper radiator hose.....  but then there are more hose clamps...

 

Grrrrr

Hag

Edited by Haggar
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@Tractorman I am so sorry.  I think when I was typing that last message I was too excited as everything seemed normal.  The gauge DID NOT go down when the system was pressurized, to spec, in test number one.  Held pressure just fine with no loss.  Needle held right at 16 PSI and didn't move at all.  I will continue to monitor engine coolant to be 100% certain that it is not using any during operation.     

 

Thank You all for your help!

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Posted (edited)

@sooxies, one of your best indicators of cooling system problems can be observed by watching the coolant level in the overflow container.  If it is checked first thing before you drive it for the day, it should be at its lowest level.  If you check it after you just parked the truck, it should be at its highest level.  If you check the level two days from now before you start the truck and it is 20 degrees colder outside, then the coolant level will be even lower than the two days previous.  The point is, is that the coolant level will probably never be the same and that is normal.  If the coolant level remains the same when checking the level under different conditions, that is a strong indicator there is a  problem.  So, the question always is - is the coolant level at the level it should be for the current conditions?  You get the picture...

 

I hope all is well.

 

- John

Edited by Tractorman
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