Cooling system questions...

[Phatty]

So I installed an aluminum radiator in my '78 FJ40. I seem to be chasing a leak through the cooling system. I have been replacing hoses along the way and have replaced the radiator cap. I have burped the cooling system to make sure all air removed. It feels like I am getting to much pressure in the lines too fast and coolant is seeping out wherever it can. I did not hook up the rear heater yet. Could this be why? The cap that came with it was a 1.1 or 16 psi. I have replaced it with a 0.9 / 13psi cap. Lower pressure on radiator cap? My overflow for the coolant is not coming in or going out.
The radiator cap is a 45mm.
Thanks in advance!

 

[Phatty]

Here is a pic of the radiator

 

[3_puppies]

does it happen when run with the rad cap off?
did you forget a rag in a hose and now it is plugged/blocked flow of coolant?

 

[php74]

Where is it seeping from exactly. Also is it running long enough to open your thermostat? 160 or 180 degrees or so

 

[emac]

I was having an issue and it turned out to be a freeze plug under the valve cover that was leaking! You may want to run it with the front end higher than the rear. Let it run with the cap off and see if you can get any more air out. Hopefully it is just an air pocket. Is your thermostat installed properly (gaskets) and working? Overheating?

 

[sggoat]

does it happen when run with the rad cap off?
did you forget a rag in a hose and now it is plugged/blocked flow of coolant?

If it leaks with the cap off, it should leak while just sitting idle(not running) The water pump does not produce any significant pressure(being a centrifugal pump without any significant pump seals or tight clearances). it is designed for flow only. Pressure is developed when the heat from the engine begins expanding the water, eventually turning it to saturated steam. The cap allows the saturation temp to rise somewhat, so that the coolant stays in the liquid state beyond the saturation temp @ atmospheric pressure(212) From the pic you posted, this rig is not on the road yet, so temps would be way low compared to that. If you are having leaks now, in that state, they could be much worse when the rig is on the hwy @ 55 mph!
Best you continue to follow your hose check and replace scheme(I don't think your cap is the problem)

 

[Phatty]

does it happen when run with the rad cap off?
did you forget a rag in a hose and now it is plugged/blocked flow of coolant?

I haven't tried it with the radiator cap, i did try with the cap loose though. Still had some coolant seeping at the heater.