Coolant Problem

[jongray1810]

I am new to the forum. I have an 4 Liter Explorer 4x4 SOHC XLT 1998.

Over the holidays I replaced the water pump and theromostat and a few dodgy hoses around them because the water pump was squeaking on start up and there was a leak on top of the thermostat housing that turned out to be due to the theromostat seal.

Got it all back together and it seemed fine - however driving out a day later the temp guage went off the dial, I stopped and found most of the coolant in the expansion tank. I gingerly opened the radiator cap and found it empty (naturally) - I filled it and emptied the expansion tank into a container and drove on ... all was fine. Next day same deal, just as the engine gets hot and the thermostat opens (presumably) the expansion tank fills and the temp guage goes off the scale. I am carrying a 'fix it kit' and stopping every trip when the engine starts from cold going through the same charade of filling the radiator and emptying the expansion tank.

I have tried ...
- burping the car (uphill slope, open radiator cap while heating up with heater and AC on)
- checking the thermostat is in the right way round), belt is on correctly etc
- put the old thermostat back in incase I bought a wrong one
- replaced the radiator cap

Another odd thing is when I put the old thermostat back in and when I replaced the radiator cap the car worked fine for 1 - 2 days then this starts all over again.

No significant leaks and the coolant is where it should be each morning.

The pump that was sold to me was listed for a 2 wheel drive model not a 4x4 however it was the only one with the right hose fittings and it fits the manifold.

Bottom line once hot and 'replensished' the thing seems to work fine although I have only driven 25 mile journeys. Clearly some sort of overpressure .... any ideas?

 

[DBNathan]

I have a similar problem with my 97 explorer. temp gauge only went to halfway but had no heating in the car checked the heater hoses and rad hoses. heater ones were warm and top rad was hot, lower was cold. So i changed out the thermostat was fine for a couple of days then did the same today.

No heat in the car, lower rad pipe cold, oh and there is NO pressure in the rad or pipes after driving rad water is luke warm. The only issue i have found is the heater flap selector in the heater box is broken so i cant select hot or cold, I was thinking that maybe the reason for no heat was the flap had got stuck on the cold side. but that wouldn't explain the hot top pipe and cold lower even after a 10 mile run in the car

 

[albi1cnobi1]

Sounds like a clogged radiator. Possibly when you did all that work you stirred up some gunk and it ended up in the radiator.

 

[jongray1810]

The heater pipes get hot on my car too but the heating works fine. In my case it only seems to happen on the transition of the thermostat opening - my next plan is to run without a thermostat and see what happens.

 

[wood1]

Not that I am sure it's your problem, but I have personally seen new thermostats that are no good.

 

[DBNathan]

I ran mine with no thermostat for a few days while i had to wait for one to come in. Didn't have any warmth and even after a 20 mile run to a hospital appointment i was able to remove the rad cap with no blow or pressure and rad was luke warm.

 

[Torqueranger]

Did you check any of the hose ??? Sometimes the hose collapse inside them selves..

 

[jongray1810]

Thanks - hoses all ok, I am going with a clog and new thermostat (I'll do a check on old and new before I replace). BTW I have been taking off the plastic upper inlet manifold to get to the termostat but have read you can get it out without all that hassel ... I'll try that too over the weekend.

Thanks for the suggestions, I will leave an update when I have completed this.

 

[DBNathan]

been and checked mine and is now working like it should again normal temps etc, must have had an air lock.

 

[jongray1810]

Mine seems to be fine now too. I flushed very carefully...
- removed radiator and flushed it top to bottom, and vice-versa
- flushed block from thermostat orofice into the block and out via the lower radiator hose
- from lower radiator hose back up
- from both heater hoses

Refilled very carefully...
- radiator cap off and filled slowly from the thermostat orofice
- put new thermostat in and opened upper heater hose and filled from the radiator
- sealed upper heater hose and completed from radiator

No gunk I could see came out in the flushing so I think air lock or thermostat were to blame although both old and new t'stat opened at about the same temp (preinstallaiton test), the old one felt a bit sticky on opening by hand and may not have opened as far but I cannot be sure.

I have run twice from cold and when the thermostat opens you can see a small drop in t on the guage. I hope this episode is done.

Thanks to everyone who made suggestions.