Hoses feel hard and shoots coolant out overflow

[WadiaAbushanab]

I have been struggling with this issue for about a month or so. I had to fill and bleed the cooling system, as I have done many times before, but now I’m having issues.
Hoses feel very hard after driving, I don’t remember it being like this, and the overflow tank is constantly being filled to the top with coolant, then spraying coolant all over my engine bay. It’s overheating, I thought it would be air bubbles, but I’ve bled it many times before with no issues, but now it’s just doing this. The thermostat is opening because the bottom hose and the bottom of the radiator is hot, so maybe I have a dead water pump? Or any other ideas?

[rridge]

A valve in the radiator cap controls the pressure in the cooling system. An old cap can create eratic pressure or no pressure at all and can allow air into the system through poor sealing in the radiator neck.

[Nut124]

I feel your pain. Been following your troubles.

Water pumps do not really fail.

Here is what I'm thinking:
- The external thermos is installed in the wrong orientation. This can happen pretty easily, even to the experienced. To me this is the most likely cause. Different makes may look similar exeternally but are plumbed different internally. Porting must be examined carefully.
- There is an unknown thermostat in the head, under the coolant outlet. known to happen.
- The radiator is plugged. Never seen myself but have heard of it.
- The entire coolant system is gunked up. I have never seen nor experienced this but I hear it could happen if incompatible coolants are mixed.

Does the radiator fan come on and run? It should run non-stop if that hot.

[TX82FIAT]

The overflow can be caused by a radiator cap, water pump, thermostat, or even the radiator. If hoses are full and hot going into and out of the T-stat on the passenger side than I would not expect that is the issue as hot/full on all hoses would indicate the T-Stat is opening. I would lean on some restriction causing very high backpressure as the coolant may not be able to flow. These cooling issues can be difficult to diagnose. A new radiator cap should be about $10 ordered on-line and received in a couple days if you want to try that first. Not a bad idea to have a spare on hand anyway. How was the car running before you bled the system? You said "I had to fill and bleed the cooling system". Why? Was there a reason other than preventive maintenance that spurred the coolant bleed. Have you checked the oil consistency and is there any white/blue or extra black smoke coming from the tailpipe? Good luck.

[WadiaAbushanab]

The overflow can be caused by a radiator cap, water pump, thermostat, or even the radiator. If hoses are full and hot going into and out of the T-stat on the passenger side than I would not expect that is the issue as hot/full on all hoses would indicate the T-Stat is opening. I would lean on some restriction causing very high backpressure as the coolant may not be able to flow. These cooling issues can be difficult to diagnose. A new radiator cap should be about $10 ordered on-line and received in a couple days if you want to try that first. Not a bad idea to have a spare on hand anyway. How was the car running before you bled the system? You said "I had to fill and bleed the cooling system". Why? Was there a reason other than preventive maintenance that spurred the coolant bleed. Have you checked the oil consistency and is there any white/blue or extra black smoke coming from the tailpipe? Good luck.

I installed a new intake manifold and carb, and there was a coolant line running through the old intake which emptied a lot of coolant so I had to fill it after and bleed it. Oil looks normal. The radiator is only 6 months old along with the thermostat both from Autoricambi. Maybe it’s gunked up. There seems to be a film of rust or something brown at the top of the overflow tank and radiator, but just a film, however there seems to be small specs of stuff too.

[Nut124]

Did it overheat before the intake swap? What does the temp gauge show when you think it is overheating?

If it ran fine before the intake swap and the only thing done was to refill the cooling system, then it would seem it'd have to be air or gunked coolant. I have never had trouble with air but have heard others having. I hear some coolants may not mix well with others, could gunk. Never seen it myself.

If it ran fine before and the thermostat was not touched, then;
- Jack up the front and burb the air out of the cooling system. This is what I have done for seemingly decades. Never had an overheating problem.
- Examine the cooling system for clots, signs of solidifying. Never seen this, but have heard of it.

I still think the most likely cause is the external thermos in incorrect orientation.

Or, Perhaps your radiator fan does not turn on?

Overheating the engine will cause head gasket to fail.