Coolant Issue

[Stu606]

Hi guys,

I need help with my wifes 2000 4.0SOHC AT 4x2

Every weekend I need to put a little coolant into the radiator (appox 4-6ozs maybe 8ozs on occasions), and there always seems to be a little air in the top hose , as it goes into the metal hose on top of the valve cover. Which i loosen to let the air out and ensure coolant flows out when i top it up. We live in Nassau Bahamas so the coolant temp is already 80-90 deg ambient before you start the engine.

I recently did change a head (passenger side, rh, genuine Ford exchange) due to silicate drop out blocking the cooling passages and creating airloocks when the coolant was changed causing it to overheat. This vehicle had been sitting for 7 years and its now got 20,000 miles (twenty thousand). 13,000 when we bought it.

It runs fine just the coolant issue. Temp gauge is where it should be. The coolant goes into the expansion tank but does not return to the rad on cooling. The tube between the two is good and sealed and the rad cap is new. As far as i know no external leaks. Radiator looks new ... 20,000 miles etc.

This is really bugging me as the car is a nice one with very low milage.

Should the coolant level always be full, to the bottom of the radiator neck, and if the coolant excess gets put into the exp tank then surely it should suck it back as it "cools".

Any ideas , its driving me nuts.

Many thanks

Stu

 

[jlsparky7]

First of all, lucky you living in the bahamas. I live in Michigan and we got 4 inches of snow last week and expecting more this week.

The radiator should always be full cool or hot. Unless the water is evaporating or you have a head gasket leak then the problem is its escaping from the engine, rad, or tubing. Have you done a thermostat yet? Might be leaking onto the block then evaporating when you drive it. There is plenty of room for the coolant to sit under the thermostat before itll drip down onto th ground. Heres a vid to help you out of you need it.
http://www.youtube.com/watch?v=C9d4Jzp9ef4

 

[Trefty]

I'd try replacing your rad cap. Sound like you might not be getting the proper pressure in your system if it's not drawing any coolant from the overflow tank.

 

[Stu606]

Thanks guys,

Yeh I think I'll try the new cap. Its not that old but not worth not doing either.

Pretty sure its not leaking anywhere externally. But it runs great and starts as it should. But I believe it should suck the coolant back in as it cools. Maybe the hoses have had it ???

The cooling system has been flushed twice and I always use a good Shell coolant. 25-30%.

I even installed a flushing kit in the heater hose to really clear it out and it comes in handy to vent the air out of the engine.


Just out of interest how easliy shoud a 4.0 SOHC purge all the air out of the system when doing a flush and coolant change. Is there a specific proceed ure to follow. I open the flush fitting, crack the top hose open at the metal pipe and put the heater on full hot before I park the night before. (otherwise I never use the heater except for demisting occasionally - its 8pm and 80 deg at the moment)

Thanks again