Bleeding of cooling sysyem

[NewDan]

Hi Guys, have a 95 GQ with a TB42e. Blew a heater hose and just changed it would anyone know if you need to bleed the cooling system on these. it seemes to come up to normal operating temp and sit there ok, but there is no pressure when you take the radiator cap off and the radiator hoses seem soft when its running. Also the top hoses gets very hot while the bottom is cool enough to grab. Any help would be appreciated.Dan

[boots]

Run it with your heater on and cap off , let it get to running temp and top up . stop running and let it cool down , top up again . then put your radiator cap back on .

[NewDan]

Thanks for that boots, it didnt drop at all with the cap on, thats what worried me a bit but ill try it with the cap off. Really appreciate the quick reply and the advice.

[YNOT]

Park the car with the front facing uphill and run the engine at 1200-1500rpm with the heater on and the radiator cap off. When you see the coolant start circulating through the radiator let it run for another minute or two then top it up and put the cap back on.
The system will build up very little pressure idling in your driveway but if it still does not pressurise after a decent drive I would be checking for leaks and replacing the radiator cap.
Hot coolant enters the top of the radiator and cooled coolant exits through the bottom so as long as the coolant is circulating what you are feeling is normal.

Tony

[boots]

Mate no worries ,just noticed your weapons a 95 model , and its just done a hose . you may want to consider changing your other hoses and stuff . ie clamps and cap . its cheap insurance leading into summer and peace of mind .

[NewDan]

Yeah I reackon thats good advice, I just notice the bottom heater hose is looking a bit tatty so I do them all as a priority now.

[NewDan]

Is there a way to tell if the collant is circulating, havent been able to make the level drop. took it 30 k down the road and temp sits on about 1/3 without moving....reackon i may have to get the system pressure test as still no pressure at all.

[Clunk]

You should be able to see the coolant circulating when you take the radiator cap off (when engine cool), the coolant will come throught the thermostat housing return pipe to the radiator cap................. once the engine starts getting hot the thermostat will open then the coolant will flow through the engine instead.......
If the top hose feels soft from the outset, then maybe the thermostat is stuck in the open position.................. this happened with mine a few months back.

[YNOT]

Is there a way to tell if the collant is circulating, havent been able to make the level drop. took it 30 k down the road and temp sits on about 1/3 without moving....reackon i may have to get the system pressure test as still no pressure at all.

Take the radiator cap off (be VERY careful if the engine is hot) while the engine is running and look at the coolant, it should be flowing away from the top radiator hose - note that coolant only circulates when the engine is hot and the thermostat is open.

Tony

[NewDan]

Yeah thanks guys, I was starting to wonder if a thermostat problem and its looking more like it all the time as there is no coolant moving, its not droping, no pressure at all. In central Victoria at the moment so will drop into a mechanic here in the morning before the drive back to Melbourne to be on the safe side. Really greatfull for all the responses - what an amazing resourse this forum is. Cheers, Dan.

[YNOT]

A thermostat that is stuck open will cause the engine to take a long time to warm up. A thermostat that is stuck closed will cause the engine to overheat within a few minutes of start up.

Tony

[Clunk]

If the thermostat was stuck open, would the top hose remain relatively soft but get hot and if it was stuck closed hose would be hard and cool?

[patch697]

If the thermostat was stuck open, would the top hose remain relatively soft but get hot and if it was stuck closed hose would be hard and cool?

No not always.... Most modern cooling systems have a small bypass built onto them & this will get some heat into the top hose but as Tony said if the thermostat is stuck shut the temp will fly up pretty quickly.

If there is a beach in the cooling system somewhere, it wouldn't matter if the thermostat was jammed open or closed, the hose (in good condition) will remain soft as the system will be unable to generate any pressure through heat expansion.

[Ade]

Is it normal that my lower hose is way much softer compared to the upper hose no matter when the engine is cold or hot? Does it have any effect on the cooling performance..?

[NewDan]

The sender for the temp guage would obviously be on the engine side of the thermostat ???. It doesn't overheat at all it just wont build up any pressure. Got it booked in for Wednesday now to get the whole cooling system checked told him to change every hose on it as well as I dont know too much of the history of the truck, I figure any hoses that are in reasonable condition I can just throw in the back to keep as emergency spares. Will post the outcome when I know.

[fatboy-71]

Hey guys I have a question, just replaced head gasket, thermostat, flushed radiator, flushed block, temp still runs around 2/3 to 3/4 ford maverick 4.2ltr petrol manual, top hose is quite hot and bottom is near cold, what could it be????

[scottsauto]

i cut the bottum out of a water bottle and tape the top so it fitts snug in the radiator, fill it up with coolant and run engine until hot, ive found this to work.

[scottsauto]

you shuold feel a big differance in temp between top and bottum radiator hoses if your thermostate doesnt open

[tiny]

In a seperate thread that I started re fan clutch, I did the old trick and assumed the worst and worked backwards to no avail..
Today I used the driveway ramp( I live in unit block ) and bled system with heater on and low and behold the cap opening burped and farted after a few minutes!!!
It now sits on 1/3 temp with ac on even holding it a gear lower to keep motor hot..

Massive lesson learnt , don't assume radiator mob cares for your truck like you do.. I was minutes away from new alloy radiator and thermos at their suggestion.

This forum has saved me 10 times sponsorship and I'm still new to patrols.
Big thanks to all..