Water temp gauge just shot off the scale

Discussion in 'All Things Technical' started by andyscoob, Jun 8, 2017.

  1. andyscoob

    andyscoob Active Member

    Evening all,

    Just after some advice if at all possible, got my classic out of the garage tonight to take it for a run. The engine temp was fine, it raised as per normal to the middle after a few minutes and then suddenly whilst driving it shot off the scale and was indicating that my car was overheating. No warning lights or anything have come on.

    I don't appear to have any water leaks, coolant that is in the overflow tank is fine and the level is reading normal, Engine temp appears to be no hotter than normal when I popped the bonnet and lamco oil pressure and oil temp sensors are reading normal.

    Any help is greatly appreciated.

  2. ZANNY


    Temp sensor on rad faulty?
    Have you topped your coolant up lately?
    Are your fans operating?

    Can't be stat as the fail on open
  3. andyscoob

    andyscoob Active Member

    I will look into the sensor on the rad. The coolant was replaced completely about 6 months ago due a pipe perishing and it started to leak. The fans are operating as they should.

    I am wondering if this has been building for some time as the car has been running rough (revs going up and down) on idle for a while. I changed the MAF sensor recently as that was playing up, this made things better but it is still not 100%.
  4. ZANNY


    Check all pipes again rough idling doesn't sound good
    sounds like could be maybe airlocked I hope it's not the ... hg as these impreza s do have shitty temp gauges by the time it tells you its hot it's baked all ready, hope you get it sorted pal with least hassle
    let us know how you get on
  5. andyscoob

    andyscoob Active Member

    All pipes checked, I seem to be weeping a little coolant from the pipes near to where the engine coolant temperature sensor is located. Also I was able to undo the old sensor by hand, surely this should have been tighter than that considering its pressurised? New sensor is on, just need to refill the coolant now and bleed it and then test it out. Hoping this will sort it out.
  6. andyscoob

    andyscoob Active Member

    Bl**dy car still not right. I think I am going to have to bite the bullet and get the head gasket done. Everything I can do myself has been done and made no difference. :-(
  7. ZANNY


    You sure you haven't airlocked it mate??
    Pretty tricky to sort if it's airlocked and that switch shouldn't be lose enough to be opened by hand in first place to be honest

    Re do the coolant or get someone competent enough to make sure it's not an airlock hope it's not headgasket mate
  8. andyscoob

    andyscoob Active Member

    I have had a neighbour look over the car with me today, he works on all his cars himself. He shares my view that the airlock appears to have been removed.

    So far I have put a new coolant temperature sensor in it, made no difference. I have put a new thermostat in and renewed all the coolant, made no difference. Also I tested the old one tonight after seeing a you tube video about boiling it in water and it should open, my old one which I removed is working.

    What I did find out today when renewing the coolant was that there was a load of what I can only describe as brown sand like material in the top of the radiator hose going to the overflow tank, this was completely blocked and I have no idea how long it has been like that.

    I also fitted a spare set of clocks into the car to see if by some long shot the gauge was faulty, Gauge was working fine.

    Before I bite the bullet and just get the head gasket done am I correct in thinking that I could change the radiator and the water pump to see if this makes a difference?

    PRICE wise I am being quoted £850 - /£1000 for the head gasket to be done, does this seem about the correct price to pay?

    Thanks so far for the help I have received.
  9. ZANNY


    Get it over to cams performance or your local subaru specialist mate who give it all the tests etc and have it sorted for you
    £800/£1000 for a headgasket change? Who gave you that quote if you don't mind me asking
  10. andyscoob

    andyscoob Active Member

    God I love my classic. She has been into a garage who I have used before and they have never let me down, they have carried out all the relevant tests and they are advising that head gasket is fine and the engine is actually doing everything it should, the coolant is getting around the engine and the sensors/thermostat are working.

    They have advised that I need an auto electrician out to the car, they have advised that the fans are not coming on now and the sensor appears to have a live feed on it or something like that which is should not have and this is causing the sensor to send the gauge in the car false readings.

    Does anyone know of any good auto electricians?
  11. andyscoob

    andyscoob Active Member

    Not been able to get on here for a while but the classic becoming a pain in the bum recently.

    Thanks to Adge at Adgespeed for helping me get the car running right (sort of). The car runs a lot better now and does not cut out, overheat or anything like that. However the idle on the car is not sitting right, it seems to idle fine for a while at about 700/800rpm but then it starts dropping to 250rpm then recovers and then drops again. Am I right in thinking the throttle body could be a cause for this happening?

    Also on Thursday night on the way home from work on the motorway the gearbox decided it did not like 5th gear anymore and just keeps popping out of gear whenever it is in 5th. All other gears are fine. Was really hoping to come on the run out on the 22nd October but dont think I will be able to get the gearbox sorted in time.
  12. scooby251

    scooby251 Well-Known Member

    Sounds like you have a few separate issues.
    When the car is idling rough. Have you tried tapping the top of the idle control valve with the backend of a screwdriver? They do stick sometimes.
    If that doesn’t work loosen the two screws at the side of the idle control valve and twist is slightly when the engine is running and see if that helps and re tighten after.
    Last edited: Oct 17, 2017
  13. scooby251

    scooby251 Well-Known Member

    Failing that. Take a trip to Brian at Cams

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