Hot engine, cold rad, missing thermostat

4th January 2022, 23:56

Hi All,
The other day after a small trip, I noticed that some water was falling from the radiator. It was not a leak, but getting out from the cap.
The water was cold but it shouldn't. I had to go so it cold down all, when I restarted the engine, I noticed that it was overheating, but the radiator was cold, and full of water, cold too. I thought it could be a faulty thermostat, but when I went to changed it, it came out my car was missing it. So I thought it could be the water pump, but it seems that it was changed recentely from the previous owner, so the radiator.
I still havent tried to flush the coolant and refill it,
Is it possible that it's just bubbles in the radiator?

5th January 2022, 19:43

Quote:

Originally Posted by fastuko

Hi All,
The other day after a small trip, I noticed that some water was falling from the radiator. It was not a leak, but getting out from the cap.
The water was cold but it shouldn't. I had to go so it cold down all, when I restarted the engine, I noticed that it was overheating, but the radiator was cold, and full of water, cold too. I thought it could be a faulty thermostat, but when I went to changed it, it came out my car was missing it. So I thought it could be the water pump, but it seems that it was changed recentely from the previous owner, so the radiator.
I still havent tried to flush the coolant and refill it,
Is it possible that it's just bubbles in the radiator?

The radiator could be blocked?

Also is the engine actually overheating? There is always a chance that the gauge reading is faulty. does the warning light come on?

6th January 2022, 13:04

Hi MartinObviously
This morning I flushed the coolant and refill following strictly the instructions about the 3 valve to open adn be sure all the air came out. And it's working. So I can say the problem was that, and it's resolved. But i noticed, while I tried to warm the engine, other small things. Like that the fan didn't start anymore, not even at slow speed, the air from the internal heater was cold, and some white smog from the muffler. All these 3 things together, could be related to an engine running colder, cause of the missing thermostat?

7th January 2022, 00:33

Quote:

Originally Posted by fastuko

Hi MartinObviously
This morning I flushed the coolant and refill following strictly the instructions about the 3 valve to open adn be sure all the air came out. And it's working. So I can say the problem was that, and it's resolved. But i noticed, while I tried to warm the engine, other small things. Like that the fan didn't start anymore, not even at slow speed, the air from the internal heater was cold, and some white smog from the muffler. All these 3 things together, could be related to an engine running colder, cause of the missing thermostat?

Yes the missing thermostat could definitely be the problem, especially on a cold day the engine might never heat up properly.

9th January 2022, 08:49

Good morning MartinObviously, are you having a good weekend?
Unfortunately the problems keep going. Yestarday a small but fast ride, i parked the car and fan was running. After a while I noticed some water dripping from the radiator cap. The car is still withou thermostat. Toghether with the new thermostat I'm going to get a new cap (it could get air inside from a faulty one?), and a new temperature sensor just to be sure. But I have the feeling this is not going to resolve anyway. Any suggestion?

9th January 2022, 14:23

Quote:

Originally Posted by fastuko

Good morning MartinObviously, are you having a good weekend?
Unfortunately the problems keep going. Yestarday a small but fast ride, i parked the car and fan was running. After a while I noticed some water dripping from the radiator cap. The car is still withou thermostat. Toghether with the new thermostat I'm going to get a new cap (it could get air inside from a faulty one?), and a new temperature sensor just to be sure. But I have the feeling this is not going to resolve anyway. Any suggestion?

Remember it will spill excess coolant from the radiator, the "full" level is quite far down on the chamber.

9th January 2022, 17:10

Yes I know, but it was too strange that the fan was running at maximum speed after a short ride. Anyway i took another close look today and it seem that rad cap was changed, with one at 1.1 bar. It should be 1.4 bar doesn't it? Considering that in this way the boiling temperature is lower than it should, and I'm running with just water, this could be cause of steam and indirectly air inside the circuit?

9th January 2022, 23:08

Quote:

Originally Posted by fastuko

Yes I know, but it was too strange that the fan was running at maximum speed after a short ride. Anyway i took another close look today and it seem that rad cap was changed, with one at 1.1 bar. It should be 1.4 bar doesn't it? Considering that in this way the boiling temperature is lower than it should, and I'm running with just water, this could be cause of steam and indirectly air inside the circuit?

Didn't realise you can get 1.1 caps, yes 1.1 would boil at 102C.

1.4 would be something like 109/110C

With no thermostat though, it seems unlikely that boiling is a problem.

10th January 2022, 10:31

Yes, that's true. But My real problem is that I get air inside the circuit. Considering that a lot of water was coming out from the cap yestarday, I could state that a lower pressure cap, get more water out from the circuit, and that space get filled with air instead... it has it's own logic now, what do you think?

13th January 2022, 15:08

Have you bought this car recently?

Missing thermostat and air suddenly appearing in the cooling system, excess cooling system pressure and showing signs of overheating could be a head gasket problem.

13th January 2022, 18:12

Yes I bought it recently.
The head gasket was made new recently, as the water pump. So i think the problem should not be in neither ones

15th January 2022, 18:24

Quote:

Originally Posted by fastuko

Yes I bought it recently.
The head gasket was made new recently, as the water pump. So i think the problem should not be in neither ones

And you bleed it correctly?

Engine off, cold, header of water on the radiator. (the important bit is the engine is OFF)

radiator bleed screw, open then close after no air.
Thermostat bleed screw, open then close after no air
Heater matrix bleed screw, open then close after no air.

If you're following that exactly, then there should be absolutely no chance of any air getting into the system.

22nd January 2022, 10:22

Yes, I knew it and did it correctly.
I have some news:
I changed the rad cap, the sensor and added a thermostat. And it's working, I can say the problem was the cap, yestardau I took a 6okm ride with no problem at all.
The only strange thing I can't explain, heater still give cold air. I touched the hoses that bring hot water to the heater and they are cold even if the engine it's hot, is there maybe an obstruction, maybe made by the mechaninsh as a fast fix for something?

24th January 2022, 14:00

Quote:

Originally Posted by fastuko

Yes, I knew it and did it correctly.
I have some news:
I changed the rad cap, the sensor and added a thermostat. And it's working, I can say the problem was the cap, yestardau I took a 6okm ride with no problem at all.
The only strange thing I can't explain, heater still give cold air. I touched the hoses that bring hot water to the heater and they are cold even if the engine it's hot, is there maybe an obstruction, maybe made by the mechaninsh as a fast fix for something?

That's a good start, yes there could be a blockage.

It's safe to block these pipes, never bypass them.

Try removing the hoses and flushing cold water though the heater core