A little warm this morning
Discussion
Ah the delights of summer, not! After 3 miles this morning, temp guage off the scale (120+), no fans on. Stopped, radiator warm, (hand hot easily) engine tinkle, tinkle, twang and rather warm.
Gentle, very, creep home and get the daily diesel donekey out.
Am I correct in assuming that the thermostat has stuck?, if so which one do I need for a 99, 450.
regards from a rather warm
dave
Gentle, very, creep home and get the daily diesel donekey out.
Am I correct in assuming that the thermostat has stuck?, if so which one do I need for a 99, 450.
regards from a rather warm
dave
Did it go straight to 120 or rise gradually as you might expect?
Could be a faulty gauge or sender unit. I've had air locks and low coolant a few times over the years but it's never got that hot and the fans always cut in. Around 100 is the highest I have ever seen and that was when 2 litres of coolant had gone missing.
Suggest a test using the blower with the engine warmed up a little as from experience, I find that the heater/blower is a great indication of the state of the cooling system:
1. The temperature of the air when in the max hot position is a really good indication of the coolant temperature. If it is nicely warm, the gauge would usually be at around 70 deg. If the gauge is at 90, the air is so hot that you can't keep your hand by the central heater vent with the fan on for very long as it burns. Test the temperature of the output air with you hand, using max hot position and blower motor at max speed.
2. If you get a small amount of air in the system, you can hear bubbles going through the pipes as you open the hot valve from the cold position.
3. If you get low coolant, the first sign is that the heater will start blowing colder when engine idling but if you rev the engine a bit, it will suddenly go hot again. If the coolant drops really low, only cool air will come out even on max hot with a warm engine regardless of revs.
If the fans aren't cutting in and the blower air is not burn-your-hand hot, and the gauge is showing 90deg+, I'd bet your gauge / sender / wiring is faulty.
If the blower air is scalding, then yes maybe you have a blocked thermostat / failed water pump or very low coolant.
Of course, don't run the engine for too long if you think it is in danger of overheating.
Could be a faulty gauge or sender unit. I've had air locks and low coolant a few times over the years but it's never got that hot and the fans always cut in. Around 100 is the highest I have ever seen and that was when 2 litres of coolant had gone missing.
Suggest a test using the blower with the engine warmed up a little as from experience, I find that the heater/blower is a great indication of the state of the cooling system:
1. The temperature of the air when in the max hot position is a really good indication of the coolant temperature. If it is nicely warm, the gauge would usually be at around 70 deg. If the gauge is at 90, the air is so hot that you can't keep your hand by the central heater vent with the fan on for very long as it burns. Test the temperature of the output air with you hand, using max hot position and blower motor at max speed.
2. If you get a small amount of air in the system, you can hear bubbles going through the pipes as you open the hot valve from the cold position.
3. If you get low coolant, the first sign is that the heater will start blowing colder when engine idling but if you rev the engine a bit, it will suddenly go hot again. If the coolant drops really low, only cool air will come out even on max hot with a warm engine regardless of revs.
If the fans aren't cutting in and the blower air is not burn-your-hand hot, and the gauge is showing 90deg+, I'd bet your gauge / sender / wiring is faulty.
If the blower air is scalding, then yes maybe you have a blocked thermostat / failed water pump or very low coolant.
Of course, don't run the engine for too long if you think it is in danger of overheating.
Edited by taylormj4 on Monday 14th July 12:50
Thanks for all the thought. Had a play this evening. Water level is where it always is, thus no leaks. Checked fans by shorting out otter switch. fans cut in nicely. Started engine and it gradually warms up and just keeps on going up! After 5 minutes temp gauge is reading 110 degrees, engine and heater air exceeding hot, radiator and swirl pot cold.
will play again later in the week by 'cracking' swirl pot to see if air present. Hopefully I will hear a hiss before water comes through. However I am still favouring the stuck thermostat.
thanks again
dave
will play again later in the week by 'cracking' swirl pot to see if air present. Hopefully I will hear a hiss before water comes through. However I am still favouring the stuck thermostat.
thanks again
dave
Where are you checking coolant level, swirl pot or expansion tank,? I had an issue where the expansion tank was full (well normal level) but swirl pot was empty due to rad leak, base of expansion tank was blocked and all looked OK level wise, but wasn't, overheated quick then too as no coolant in system.
In your description of the engine warming up, you don't say if the fans cut in. Presumably not.
If they run when you short out the switch but not when the engine warms up normally, I would favour the otter switch being duff. But if the rad stays cold, as you indicate, I'd agree the thermostat isn't opening.
You could remove it completely and then retry to be sure.
If they run when you short out the switch but not when the engine warms up normally, I would favour the otter switch being duff. But if the rad stays cold, as you indicate, I'd agree the thermostat isn't opening.
You could remove it completely and then retry to be sure.
Edited by ianwayne on Monday 14th July 23:04
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