1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.
  2. Welcome To LandyZone!

    LandyZone is the biggest Land Rover forum on the net. We have plenty of very knowledgable members so if you have any questions about your Land Rover or just want to connect with other Landy owners, you're in the right place.

    Registering is free and easy just click here, we hope to see you on the forums soon!

Running cool and no pressure?

Discussion in 'Land Rover Discovery' started by towsey956, Sep 18, 2020.

< Previous Thread | Next Thread >
  1. towsey956

    towsey956 Well-Known Member

    Joined:
    Nov 25, 2015
    Posts:
    1,083
    Likes Received:
    109
    Location:
    Northyorkshire
    Hi all

    There’s alsorts going wrong with disco at the moment, todays issue is that I noticed it wasn’t rite upto temperature (just below half) in the time it usually would be and the blowers not as hot as usual either so ruled out the sender/gauge. It warms up as normal to a certain point then stays there and some harder driving gets the gauge up but then it cools back off again after slowing down. When I opened the bonnet I wasn’t met by the usual heat that lives under there either, it was like it’s only been running a few mins, and also there isnt pressure in the header tank when I remove the cap. All pipes feel the same temp but not hard and I’ve checked level in tank and thermostat housing

    Please help I’m getting fed up with this

    Thanks in advance

    Towsey
     
  2. sierrafery

    sierrafery Well-Known Member

    Joined:
    Jun 30, 2007
    Posts:
    13,912
    Likes Received:
    2,130
    Location:
    West of Transylvania
    Hi. Seems very like stuck open thermostat so start from there, the easy way is to put in a new one and bleed the system well
     
    kermit_rr, Stanleysteamer and Bantam1 like this.
  3. towsey956

    towsey956 Well-Known Member

    Joined:
    Nov 25, 2015
    Posts:
    1,083
    Likes Received:
    109
    Location:
    Northyorkshire
    Thank you

    I didn’t mention that I’ve just changed the matrix yesterday so there’s now 4 jubilee clips under there aswell as the 2 pipe clamps but all seems ok there when I’ve checked

    I should of looked at the ‘stat while I was checking the level in there

    Am I rite in thinking it’s not actually the pump that builds up the pressure, and what are the common symptoms of pump failure in 300s?

    Thanks

    Towsey
     
  4. sierrafery

    sierrafery Well-Known Member

    Joined:
    Jun 30, 2007
    Posts:
    13,912
    Likes Received:
    2,130
    Location:
    West of Transylvania
    IMO a pump failure would lead to overheathing due to lack of coolant flow
     
    Stanleysteamer likes this.
  5. towsey956

    towsey956 Well-Known Member

    Joined:
    Nov 25, 2015
    Posts:
    1,083
    Likes Received:
    109
    Location:
    Northyorkshire
    Cheers

    I suppose sticky ‘stat would explain why there was pressure but then there wasn’t would it
     
  6. discool

    discool Well-Known Member

    Joined:
    Apr 25, 2007
    Posts:
    12,425
    Likes Received:
    1,305
    Location:
    Sector 12 in Kent, The Garden of England
    Yes u are, the pump is is for circulation only.
    As the coolant was drained because of the work involved in replacing the matrix it appears that air is still in the system after filling refilling, so drain again, refill slowly and bleed the system as specified for the 300tdi engine.
    It a good idea to also replace the thermostat as well if unsure, but it shouldn’t go faulty due the the previous work done.
     
  7. Stanleysteamer

    Stanleysteamer Well-Known Member

    Joined:
    Nov 22, 2013
    Posts:
    11,084
    Likes Received:
    9,537
    Location:
    East Dorset
    agree with all that, and pressure only builds up as temp builds up, see Boyle's Law!
     
    kermit_rr likes this.
  8. towsey956

    towsey956 Well-Known Member

    Joined:
    Nov 25, 2015
    Posts:
    1,083
    Likes Received:
    109
    Location:
    Northyorkshire
    Cheers for that

    It’s been bled properly 3 times now to makes sure, when the gauge and blowers cooled off it was my first port of call, I would of thought one of the pipes would of been at the top of the matrix tho rather than both in the bottom half! I hope it’s just coincidentally a sticky ‘stat that’s happened the day after I did the matrix...after all it is a Land Rover!

    There’s a thermostat coming Monday (apparently)

    So can you think of anything mechanically really bad that would stop me using it giving these symptoms?

    Towsey
     
  9. Stanleysteamer

    Stanleysteamer Well-Known Member

    Joined:
    Nov 22, 2013
    Posts:
    11,084
    Likes Received:
    9,537
    Location:
    East Dorset
    Apart from the fact that an engine that is running cool is not taking up the clearances it should so things like the pistons will be running a bit loose in the cylinders leading to possible wear, No not much at all!!!!! Only kidding. Well sort of!

    But TBH, if you are worried, make up some kind of a radiator blind and put that over the front of the rad, experimenting until you get the temp up.
    Not one for the purists but there you go. Used to have to do that for my old Mk1 Cortina in the winter. It may possibly also help push the air out. But i would be really interested to see what you find when you take the old stat out. Maybe a foreign object will be found to have jammed it open.:eek:
    So often wax stats fail closed, not open, as they overheat and then the wax comes out so it can never fully open again.
     
  10. kermit_rr

    kermit_rr Well-Known Member

    Joined:
    Dec 9, 2018
    Posts:
    7,879
    Likes Received:
    5,129
    Location:
    North Shropshire
    On my 4.0 Thor engine, the temp needle is about 1/4 at 70c and just below 1/2 at mid 80s, going to the halfway mark around 90c

    If that helps
     
  11. towsey956

    towsey956 Well-Known Member

    Joined:
    Nov 25, 2015
    Posts:
    1,083
    Likes Received:
    109
    Location:
    Northyorkshire
    Thanks for replies

    It's not running cold just not to temp, it warms up as normal to a point then that's it and I'm only popping to the inlaws and maybe shooting so not going far. I also used to put things in front of rads in old escorts and fiestas but this has A/C but I might just rake the fan off. Yeah I wasnt really expecting the 'stat to fail open, I did take the bung out for a look earlier before starting it and stat was closed with bypass open so?

    Thanjs again

    Towsey
     
  12. sierrafery

    sierrafery Well-Known Member

    Joined:
    Jun 30, 2007
    Posts:
    13,912
    Likes Received:
    2,130
    Location:
    West of Transylvania
    What you see stationary is not very relevant cos even if it's not stuck it can open right away when it gets flow... the only way to rule it out 100% is to replace it with new
     
    Stanleysteamer likes this.
  13. towsey956

    towsey956 Well-Known Member

    Joined:
    Nov 25, 2015
    Posts:
    1,083
    Likes Received:
    109
    Location:
    Northyorkshire
    Yeah hopefully will get one in Monday and go from there

    My main concern was that it could be something more sinister

    Towsey
     
  14. sierrafery

    sierrafery Well-Known Member

    Joined:
    Jun 30, 2007
    Posts:
    13,912
    Likes Received:
    2,130
    Location:
    West of Transylvania
    I have the feeling that you'll be ok with a new stat
     
  15. towsey956

    towsey956 Well-Known Member

    Joined:
    Nov 25, 2015
    Posts:
    1,083
    Likes Received:
    109
    Location:
    Northyorkshire
    Hope so but I’m waiting for it to be some rare 1/1000000 issue that basically ends up in a new engine after my recent few weeks with it

    Towsey
     
  16. tilly2

    tilly2 Well-Known Member

    Joined:
    Jul 28, 2019
    Posts:
    456
    Likes Received:
    119
    Location:
    Staffordshire
    When I bought my TD5 I mistakenly failed to adjust my nanocom and it kept coming up "Overheat"

    Radiator was cold, so I replaced the rad, and thermostat... Still the same. Rad doesn't get hot at all. I have a new waterpump but haven't plucked up the courage to replace it...
     
  17. towsey956

    towsey956 Well-Known Member

    Joined:
    Nov 25, 2015
    Posts:
    1,083
    Likes Received:
    109
    Location:
    Northyorkshire
    Well I thought it too much of a coincidence that the ‘stat goes the day after I did the matrix so I’ve bled it again (4 times now) and kept an eye on the level and the gauge is now rising to about where it used to but the blowers still aren’t very hot, in fact as I turn the blowers up it’s hardly more than warm. Even if the matrix is full of air from the top pipe upwards I can’t see it making this much difference. When I compared the new and old matrix they had a different amount of cores...could it be that this matrix just doesn’t conduct as much heat? Although when I touch the matrix it’s hot

    There’s a steep bank on one of the places I shoot I think I might go park on that and see if she takes more water

    Towsey
     
  18. Stanleysteamer

    Stanleysteamer Well-Known Member

    Joined:
    Nov 22, 2013
    Posts:
    11,084
    Likes Received:
    9,537
    Location:
    East Dorset
    Sounds like you may have had an airlock where the temp sender unit is as that can read low if it isn't in coolant.

    Looks like you are on the right track so best of luck with it.
    :):):):):):)
     
    towsey956 likes this.
  19. discool

    discool Well-Known Member

    Joined:
    Apr 25, 2007
    Posts:
    12,425
    Likes Received:
    1,305
    Location:
    Sector 12 in Kent, The Garden of England
    OK so the engine is at the the tempreture and hopfully your your happy with.
    So the only thing now is the heater its self, as heater is air blending unit are that the dampers that control the output temp are operating as they should when the dials are turned ie. open/close fully... only if that part of the system was touched in the matrix change ?
    Was the matrix sold as compatable with the 300 series disco heater system?
     
    Stanleysteamer likes this.
  20. towsey956

    towsey956 Well-Known Member

    Joined:
    Nov 25, 2015
    Posts:
    1,083
    Likes Received:
    109
    Location:
    Northyorkshire
    Well the temp gauge gets up there but still takes longer than it used to so there maybe is a bit of a ‘stat issue but it all seems a bit too coincidental to me how it was fine and with really good heaters and went straight up to temp and the the gauge never moved, then the matrix went so I bypassed it and it was all still fine, then I piped in the new matrix and this starts, it seems to have enough water and day by day the gauge has been coming up which I find odd in itself. Yes all controls are set up properly thanks, only the drivers side was taken apart but was put back together as should be and the passenger side that wasn’t touched is running the same temp as the drivers side. I think it’s the right matrix and fits nice just has slightly different cores

    Cheers

    Towsey
     
< Previous Thread | Next Thread >