Temperature linked to heater

[mile eater]

On a 1900 petrol engine (1989 G) my temperature gauge goes up when I turn off the heater and then goes back down again to normal when I turn the heater on again.

Whats the reason for this? And how do you fix it?

Mileeater

[Mocki]

hi, it would help if you told us what engine you have?

sounds like either an airlock or a blocked radiator from what you have said..... but could be other things

[Plasticman]

I have a 1.6 D and it runs fine on temp however when I stick the heater on it does drop on the gauge a bit and after 10 min creeps back up a bit.

My interpretation is that the heater matrix is in effect another radiator and is disipating engine heat.

As Mocki says thogh what engine you got and where does the needle go if you didnt use the heater?
Mike

[NOT ANOTHER LEAK]

if the needle doesnt stray in to the red and stays just over half way i wouldn`t worry too much,just call it a characteristic

[stuckin88]

On normal use the needle should run just to the right of the warning light---have the heater on full & the needle will be slightly lower because of the extra cooling---when the engine is working hard--ie driving up a mountain pass--the needle can go well to the right & the cooling fan will come on---if you put the heater on full-the needle will drop dramatically---this can also happen when standing in heavy traffic---technique for driving in hilly country is to keep revs high in low gear--let engine labour & that needle will climb high---if red light starts flashing-stop--but otherwise ok--even if needle is well to right--

[lhd]

On normal use my needle settles just to the left of the light. Also my heater is rubbish, do you think this may indicate a probem? 1983 1.6d JP.
lhd.......................