Bad fan clutch replaced...new t-stat...coolant mix correct and full.as engine warms heater producing heat.temp gauge reaches norm.heater then gets cold.suddenly temp gauge pins max.upper hose is not warm and can be squized easly...just as suddenly the gauge returns to norm-i get heat again and the upper hose is now warm and hard and truck runs well.weep hole on water pump is dry also no noise
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Re: 97 f 150 runs hot for minutes then runs ok
It could be a faulty thermostat. Did it do the same thing before u replaced the t-stat? It sounds like it's sticking closed, then all of a sudden it opens, coolant flows correctly. I'd consider changing it again. Check to make sure parts store is giving u the correct temperature thermostat also. Maybe it's too high for your Ford, delaying the opening.
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Assuming the fan works ok, it sounds like the cable from hand control to heater valve has come off or needs adjusting or replacing. Or (less likely) there is a problem with the mechanical valve. The valve needs to open to allow hot water to flow through to the mini radiator (heater radiator) and then both coolant pipes and mini radiator get hot with a warm engine. Try moving the valve lever by hand (somewhere above the clutch pedal).and If you start getting heat with the fan on the fault is the cable..
does the fan run at full speed on high, sure it does, i bet.
the heater only works on a hot engine.
180F min. and holding. some go to 200F (on newer cars)
so does it? get fully hot, and NORMAL.
the heater uses ,engine coolant to steal its wasted heat.
1: bad or missing engine coolant thermostat.
2: RAD fans stuck on, or is just too cold.\
3: no location stated. and we do get posts from the yes, north pool. or up in high Canadian provinces??? or Norway?
up in alaska we keep some engines running full time (no heated garage)
and all have rad blocked 1/2 way with cardboard.
and some we spray the whole engine with foam to keep it warm.
so not stating location (not one ever in 4000 posts) we cant answer you.
what do we do, well, I point the IR PYRO gun that the thermostat
housing, (need photo?) and see 10 less that stat rating.
if 180 i see 170 if 200 i see 190.
this is the www, and we get posts from all over planet earth.
It would appear your thermostat is stuck in the closed position , find where it is on your engine, drain coolant and remove thermostat housing and stat, replace housing(liquid gasket OK) and coolant. now run engine, turn heater controls to hot leaving filler cap off, top up any water to max and replace cap now warm up to temp until fan comes on. if all ok replace thermostat with a new one and new gasket, you could also flush the sytem out at the same time with a hose pipe by loosening one of coolent pipes and flush radiator.
check your water. if it is winter and you running your heat, then it could be your heater core. a sure sign is a wet passenger floorboard.
also check your radiator hoses. both should be hot. if one is not hot, then you have no coolant flow.
check your oil. milky, dirty white oil is a sign of a blown head/headgasket. water mixes with oil and it makes a distinct color.
if all that checks out, then check your fans. FOR ELECTRIC FANS ONLY: let the car warm up, start getting to a normal temperature (may have to drive it), and then stop and pop the hood. if you do not see a fan moving, then you have a bad relay (common) or a bad fan motor (not so common).
FOR CLUTCH FANS: there is no real way to test them. if all the steps before have turned out to be ok and normal, then you need your clutch on your fan replaced. most of them are on bigger v8s and RWD cars.
The temperature you see on the dash board gauge is not necessarily the actual temperature of the coolant. The engine has a 'coolant sensor' which sends information to the electronic control unit (ECU /PCM) and there is a separate 'sender' which governs the gauge reading you see on the dash board. The sender usually has just one wire connected to the top of it. The sender is basically a heat dependent resistor and the temperature gauge simply reads this resistance. Sometimes corrosion in the electrical connector can inhibit the correct readings, so first disconnect the sender and inspect/clean the pin with a little wire wool. Now check the coolant. First put the interior heater on maximum heat. Run the engine up to working temperature and then squeeze all rubber hoses to help shift any trapped air. Top up the coolant if the level drops when air pockets have been shifted.
The following sequence should occur when the engine is warming up.
1) When cold the engine has higher then normal revs. This is due to the coolant sensor (not sender) telling the ECU that the engine is cold and that the injectors should add more fuel to compensate for the cold condition of the engine.
2) Within about a minute the idle revs begin to drop as the coolant sensor detects the engine warming up
3) After about 5 minutes the thermostat should open. You can detect yourself this by feeling the top rubber radiator hose getting hot.
4) If you have an electric cooling fan on the radiator this should switch on about now. If you have a fan driven by a viscous clutch this will engage a little later.
5) after about 2 more minutes the face of the radiator should be becoming hot and the bottom rubber radiator return hose should become warm, then hot.
If you have an electric fan and it fails to come on then check the electric relay and fuse for it. Viscous clutch fans should always show some resistance when turned over by hand when the engine is off, if it spins freely then the clutch coupling is faulty and it will need to be replaced. A sign of faulty fan related over-heating is a car than runs at normal temperature when cruising on the freeway but overheats when standing at the lights; fan engagement is to compensate for the lack of air flow across the radiator core when the vehicle is stationary.
I hope the above helps
AFTER REPLACING THERMOSTAT DONT STOP OVERHEATING.CHECK THE COOLANT FAN CLUTCH.WITH HOT ENGINE THE CLUTCH FAN SHOULD HAVE RESISTANCE WHEN TURNING IT WITH HAND.IF NOT FREEWHEEL.FAULTY CLUTCH FAN.HAVE TO REPLACE CLUTCH ON FAN.BAD CLUTCH ON COOLING FAN WILL CAUSE ENGINE OVERHEAT.WHEN CLUTCH FAN FREEWHEELS AT HIGH SPEEDS NOT PULLING ENOUGH AIR THROUGH RADIATOR CORES TO COOL DOWN ANTIFREEZE AND ENGINE.
Two reasons that the temp won't come up...Most common is that your thermostat is stuck open. There are tests to check that but the stat is inexpensive and relatively easy to replace. Use a 195 degree (f) and make sure that you put the new one in the same way the old one came out (spring end into the engine) make sure all gasket material has been removed or it will leak and use 50/50 mix of coolant to replace any lost while working. (system does not need to be drained to do that job but you will loose some) re-fill with heater on full heat, engine running. The other possibility is that your electric fan is always on. If the fan is running with the engine cold, replace the relay (usually found behind and below R/F headlight, accessible from under vehicle with a little work.)
Make sure the reservoir coolant tank is at 'full'. Start the car from cold and observe. After a couple of minutes when the engine has begun to drop in revs ( the coolant temperature sensor should tell the ECU to begin to shorten the injection cycle as the engine warms) the top of the engine and the coolant passage to the thermostat housing should become warm to the touch. When hot the top rubber hose to the radiator should become warm and then hot as coolant begins to circulate. If the top hose fails to get hot at any time then the thermostat is at fault. If you have electrically driven radiator fans these should now come on. If they fail to come an at all you need to check the coolant temperature sensor, the electrical motor fuses and the motor relay. Lastly check the motor itself (just run a 12v supply to it directly). As the ar continues to idle, with the fans running, the bottom return hose from the radiator to engine should also become warm. If the bottom hose fails to become warm this points to circulation problems. Either the radiator had become clogged with rust sludge and needs an extensive flushing out with a high pressure hose or the pump is not functioning as it should. Quickly check that the interior heater works by asking for 'full heat with fan on full'. If the interior heater works this indicates that the main coolant pump is probably OK.
To check the thermostat more thoroughly, remove it from the car and drop it in a pan of near boiling water; the 'stat should pop open. As the pan cools, at 88 degree centigrade or so, the 'stat should pop closed. Failure to observe this tells you the 'stat is a dead and needs to be renewed.