Coolant Sprays when Driving

[drbob78]

HELP!  My 68 Riviera 430 intermittently sprays coolant all over the underside of the hood.  The system was pressure tested, and it holds pressure, and there are NO leaks.  New radiator 10 yrs ago, new hoses, new water pump 10 yrs ago, new fan clutch 15 yrs ago, new radiator cap one month ago.   I drove the 12 miles at 60 mph (all down hill -from 6800 ft. to 5200 ft.) to fill the fuel tank.  When I entered the gas station it looked like smoke from under the hood.  It was coolant that had gotten on the exhaust manifold.  The hoses were NOT pressurized and the temp. gauge never went past the half-way mark.  Filled the tank, added coolant and drove around town and then home - all up hill from 5200ft. to 6800 ft.  Temperature remained normal.  Sometimes the coolant is sprayed and sometimes it isn't.  Where do I look next??  

 

[RockinRiviDad]

Maybe your thermostat is intermittently sticking & not allowing coolant to circulate then it finds a way out somewhere??

[edinmass]

I would change the thermostat and radiator cap. Cheap, easy, and probably will resolve the issue. After that, if it still has issues, check for a head gasket leak using a chemical test. Another easy and not too expensive test.

[rodneybeauchamp]

On 3/30/2021 at 11:50 AM, drbob78 said:

 The hoses were NOT pressurized and the temp. gauge never went past the half-way mark.  Filled the tank, added coolant and drove around t

 

Usually you can feel pressure in the radiator hoses (feel tight) after it has been running if the system is holding pressure from the cap.

 

 Can you test the pressure cap to see if it holds and releases at correct pressure?

 

Is there something in the cap area preventing a proper seal.

 

Interested to see what you find?

Rodney 😀😀😀😀😀

[Seafoam65]

In my experience, a mystery intermittent leak like that is a loose hose clamp. Tighten all your hose clamps

and see if the problem goes away.

[60FlatTop]

If you pulled into my driveway with those symptoms the first thing I would to is check your brakes. One or more could be dragging.

 

 

[EmTee]

Is the coil spring present in the lower radiator hose?

[Turbinator]

On 4/2/2021 at 8:42 PM, EmTee said:

Is the coil spring present in the lower radiator hose?

The coil springs are installed on the car frame close to each tire and wheel. I put two coil

springs In the rear of my 63. For me it was exceedingly trying to install the springs. The best way to tell a never ending story is don’t tell it. 
Turbinator

[RivNut]

Sometimes a wound spring with ab OD the same as the ID of the lower radiator hose is inserted into the lower radiator hose to keep it from collapsing when a vacuum develops.

 

This thread is all over the place. 🤪 We have coolant leaks, dragging brakes, and coil spring issues.

[EmTee]

https://www.youtube.com/watch?v=fZLeaSWY37I

 

[RockinRiviDad]

Every thread on here goes in different directions 

[60FlatTop]

From what I have seen on TV the only real way of diagnosing a car overheating would require two men walking out of a cloud of steam in slow motion with tired, has been, rock music in the background.

 

[NC1968Riviera]

On 4/2/2021 at 9:36 AM, Seafoam65 said:

In my experience, a mystery intermittent leak like that is a loose hose clamp. Tighten all your hose clamps

and see if the problem goes away.

I had a small leak at my thermostat housing the other day. I tightened the hose clamp and problem solved!