Plan to replace fan sensor and heater hoses - anything I should know?

Technical Area Engine, Transmission, Exhaust etc
2

Hi

Mr car has been running hot, ( I mean it just seems to be hot), and ‘using’ water from the expansion tank. Even after an hours ‘hard’ driving on a hot day the car has not lost enough water for the radiator to not be nearly full, just the expansion tank empties. The temperature gauge though does climb to about mid way, (the climbing rather than sticking or instantly going to a point makes me think it’s working) and has not gone higher. I’ve not seen any steam or signs of boiling over. Then it dawned on me the other day that the engine fan never comes on. Shorting the fan relay makes the fan come on. Swapping the fan realy with the working horn relay had no effect and shorting GND and TFA in the diagnostic box causes the fan to come on. I’ve ordered a new sensor.

I also noticed that one of the heater hoses is very soft and plan to change both heater hoses when changing the sensor. 

I couldn’t resist a spin after work this evening so shorted GND and TFA to force the fan to on, topped up the exspansion tank and almost immediately saw an alarming amount of water flowing from that area at the rear of the cylinder head where both the suspect sensor and suspect hose are. To quantify alarming, the stream was about pencil thick. I was wondering how I hadn’t previosuly run the car dry when the flow stopped. I think this is what has been happening for weeks because I did go for a 30 minute drive, the temperature gauge didn’t go higher than 'normal. The obvious thing is to change the hoses and sensor this weekend as planned but a few questions please:

 

  1. Why did that visible flow of water stop? In a pressured system I think I’d expect to continue to be able to see a leak after such a niagra start.

  2. Should I put some sealant around the thread of the new sensor and if so, what?

  3. While I’m changing the hoses and sensor is there anything else back there I should take the opportunity to replace?

 

I have ordered a service manual but was keen to make this post incase theres anything you suggest I need to get ordered for the weekend. Plus of course I’m a bit concerned about the car.

 

Thanks very much,

 

CTOAGUN.

 

 

 

 

 

3

Have since read about Cam Angle Sensor oil seals.

4

Sorry, not read your whole post, but one tip is to slice the heater hoses off the pipes where they go though the bulkhead, if you try to twist them off you’ll probably mis-shape the soft metal heater pipes and have trouble getting the new hoses to seal properly.

5

I suppose 12 lines was a bit too much to ask. I know about not yanking on the pipes.

 

Cheers :slight_smile:

 

 

6

It was really a time thing, it’s about 50 lines on my phone screen :wink:

7


Yeah sorry, I thought later you might think me rude when I was actually attmepting humour :slight_smile:

The service manual arrived today so can have a good read before the w.e.

Cheers.