Outer Limits 4x4 Board

I have a 307 SBC with a 180F thermostat. Radiator is stock FJ40. The problem is that it dumps coolant out the overflow pipe as it warms up. It also leaks a little past the rad end of the top hose. The weird part is that it doesn't happen at normal or high temps - only when it is about half way between cold and normal. It seems to be developing excessively high pressures in the cooling system as it warms up.

Any idea why it does this and/or how I can stop it?

TIA

Ben

ive noticed the same with mine, i think theres an air pocket in one of the tanks

small block, standard 40 radiator with one sucking thermo

it heats up at idle rpms under load, like rockcrawling

im thinking of just ditching the rad and replacing it with a holden unit from a 5 litre, with twin thermos.

although. has anyone run two radiators before ?

sounds stupid, but why not ?

planb wrote:has anyone run two radiators before ?

sounds stupid, but why not ?

One problem would be be to balance the water flow between both radiators (flow takes path of least resistance). Don't think it would be worth the hassles!

had the same problem on my ford- the cap was the problem , when it got hot the spring wasn't sealing. Glad it was only a $5 fix. Failing that just get a radiator place to do a preasure test- they'll soon be able to spot airpockets or steam build up.

Thanks All.

I will try a new cap tonight. If it works I probably deserve the stoner of the week award.

BTW Planb - check out my thermo fan setup. Pics are in a General Tech thread about clutch fans and electric fans.

i saw that pic

how much were the ford fans ?

the thermo i have has a pretty good coverage over the radiator

ill probably try and pick up a an 18 odd inch davies craig fan

and whack it on the front.

planb wrote:i saw that pic

how much were the ford fans ?

the thermo i have has a pretty good coverage over the radiator

ill probably try and pick up a an 18 odd inch davies craig fan

and whack it on the front.

I'm running nice and cool, it's just the fluid loss that's bugging me. The fans haven't even come on for about three days.

Ive heard that Davies, Craig fans aren't as good as they used to be, especially for the $300 odd they charge for something that size.

2car wrote:Thanks All.

I will try a new cap tonight. If it works I probably deserve the stoner of the week award.

Well that worked

well its official

and the northsider thread of the week, with the mention of JOINING two radiators, and the major concern from fluid loss is also awarded here!!

thanks guys, good luck next week 8)