Coolant problems in my 4.0

[Hopefiend]

My temp guage is registering very low, changed sensor no change...
Coolant overflowing the puke tank...
Newer waterpump...
Blackish looking residue floating in coolant...
Top radiator hose warm lower cold, radiator cold....
Hat works but not well and not at all at idle...

Some histrory here...
Replaced both heads, all was well for a month, suddenly missing, lost compression, burnt plug, coolant nasty black looking...
Had junker engine installed...
Now i have previously mentioned symptoms...
I pulled heads off the motor that was pulled, cracked head and intake valve missing a quarter of its top...
The coolant ports are lined thickly with some fine dark grey or blackish powdery residue... this residue matches the nasty looking head gaskets that looks like its just disintegrating...

my thoughts are that the cheap head gaskets i bought failed horribly and filled the head coolant ports causing the head to overheat and crack...
shop that swapped out the motors didnt flush the radiator and heater core and therefore coolant wont flow thru radiator... barely flows thru heater core...
this also means that residue has gotten into the head ports like before...

... what are the chances of flushing all this crap out of the heads and heater core? I dont wanna tear diwn the junker motor... thats why i put it in so i can work on the motor that just came out...
I can easlily replace the radiator but i dont wanna do that just to crud it up trying to flush the rest of the system...
i need some help here!!!
Will a chemical flush get this crap out?

 

[sgtsandman]

Make sure the radiator cap hasn’t failed before you do anything. If the cap isn’t holding pressure, the coolant is going to keep expanding into the overflow and it can boil in there.

It is possible that a head gasket has failed and it’s pumping coolant into the over flow but try the least expensive and easiest fix first.

 

[Hopefiend]

Will do that
Why would the top hose be warm but the rest of the radiator and bottom hose be cool?
And/or The heat get warm while rpms up but cold at idle...
And no matter what else i have to get that crap out of the system but dont know what will brek it all loose

 

[thorsranger91]

With the idle symptoms I would suggest check the water pump. As for flushing the system due to the thin walls of heater cores avoid chemicals. Disconnect the core and use compressed air to blow out the blocks coolant passages. Use a garden hose and run it backwards through the core until it comes out clean

 

[sgtsandman]

The lower hose receives the coolant after it’s been cooled by the radiator.

It is possible your water pump isn’t moving the coolant as it should. The impeller can corrode away to the point that it isn’t moving coolant as it should but the pump spins with no problems otherwise.

One way to check that is to look at the coolant in the radiator and look for movement when the engine is warm but that is harder to do with a radiator that has a cap on the side instead of in the middle.

 

[Hopefiend]

Thanks for the suggestions

 

[ekrampitzjr]

If the radiator is cool when the engine is running, it could be clogged. Did you or anyone else ever use a leak-stop product in the coolant? (Here I go again about that stuff...)

If the radiator is clogged, you should suspect the heater core is too. And then the clogged radiator would lead to the engine overheating again.

I suspect minimum you're looking at another engine teardown and a new radiator, thermostat, water pump, and hoses.

Are you still running a factory plastic thermostat housing? Is it sound?

 

[Hopefiend]

The waterpump is off of the first motor,( the one that cracked the head) and was fairly new... they didnt change out the thermostat but i have a new one for it. The housing is metal, OHV motor...

 

[thorsranger91]

The waterpump is off of the first motor,( the one that cracked the head) and was fairly new... they didnt change out the thermostat but i have a new one for it. The housing is metal, OHV motor...

I'm still thinking it could be issues with the water pump. Is it an oem replacement or an aftermarket cheapy? Aftermarket cheap pumps tend to have variations in the veins that can cause major troubles. This was made well known with Cadillac Northstar engines and is a problem across the board. If there are variations in the veins it can cause the pump to perform in an undesirable manner

 

[sgtsandman]

I have heard about people having issues with the impeller not being properly installed on the water pump and either coming off or not spinning as it should.

 

[RobbieD]

Coolant overflowing the puke tank...

May not be your main problem, but while you're in there, make sure that the overflow hose has tight connections at both ends (radiator neck and puke tank). I've had them putting coolant in the tank, but sucking air back into the radiator when it cools because the overflow hose was loose at the neck. After a few drives the tank is over full and the radiator is low.

 

[DILLARD000]

...make sure that the overflow hose has tight connections at both ends...had them putting coolant in the tank, but sucking air back into the radiator...

Yep, keep a small SpringClamp both ends of OverFlowHose for that very reason.

 

[Hopefiend]

Clogged radiator, thermostat stuck open, air in the system!!!
I believe it also has a cracked head...
Can i replace only one head?
I have one good new head, and a good but used head... the cracked head is new and has new guts all but one broken intake valve in the the cracked cylinder port...
My thought is pressure test the newer good head for peace of mind and also one good used one from before then replace the intake valves in the ild head and uae all the new hardware from the cracked head to make 2 good heads with new valves and springs etc...
Any suggestions on if that plan is doable?

 

[thorsranger91]

Clogged radiator, thermostat stuck open, air in the system!!!
I believe it also has a cracked head...
Can i replace only one head?
I have one good new head, and a good but used head... the cracked head is new and has new guts all but one broken intake valve in the the cracked cylinder port...
My thought is pressure test the newer good head for peace of mind and also one good used one from before then replace the intake valves in the ild head and uae all the new hardware from the cracked head to make 2 good heads with new valves and springs etc...
Any suggestions on if that plan is doable?

Doable? Yes. Just for safety I would relap the valves in both heads and use a quality head gasket this time. Also head studs. I would suggest a steel multilayer head gasket. I know it sounds like overkill but after your issues I would rather be safe than sorry

 

[Hopefiend]

I have a complete head gasket replcement kit from fel pro ???
I already have bought head bolts...
I dont remember right off what brand the bolts are but i know im done with off brand ebay/amazon parts...
the engine i pulled out has a good bottom end so i want to take my 2 best heads to the machine shop to be tested and prepped for reinstallation... and return that junkyard motor (has 90 day waranty)...
what do you think on that course of action?