Member Since: 19 Nov 2019
Location: Cambridge
Posts: 15
Difficult coolant bleed
Guys,
Any advice appreciated on the topic title, having a bit of a mare tbh.
I had to give my recently new to me D3 numerous flushes to remove all kinds of crap from the coolant system - I had a real worry at one point the HGs were done but I am certain now they aren't.
It does not overheat, coolant level remains constant, no leaks visible. I have pressure tested numerous times and also vac tested and it holds both as it should.
I have the correct bleed procedure and have carried it out to the letter, slight variation and every which way I can think of.
It doesn't matter what I do I have a steady stream of bubbling from the top overflow hose into the expansion tank and in the morning when started it gurgles through the heater matrix.
How on earth do I get this air out of the system? I am at a loss, actually considering putting an additional bleed point in the heater hoses lol
Any tips for this much much appreciated, where is the air getting stuck? Heater matrix?
Has had new water pump and thermostat and like I say, hand flushed by me about 7 times. Lovely new pink coolant still looking lovely after several hundred miles, FBH works perfectly, heater blows hot (and stays hot at idle), warms up to 87 ish on the gap and no overheating.
27th Feb 2020 1:20 pm
M3DPO
Member Since: 22 Sep 2010
Location: Notts.
Posts: 8106
If that doesn’t cure it and you have bubbles coming out into the expansion tank it’s an head gasket, has the engine ever seriously overheated? - if it has its one or both head gaskets blown.It can when others can't,
It will when others won't,
It goes where others don't.
27th Feb 2020 1:55 pm
Disko
Member Since: 19 Nov 2019
Location: Cambridge
Posts: 15
I don’t know the answer to that as it’s a recent to me auction purchase. I’m not against the idea it could be HGF as I did suspect that and it’s no huge loss in the grand scheme of things. I’m trying to remain open minded lol
What I don’t get is how can it be displaying no other symptoms if that is the case? It will hold 10 PSI for 30 mins quite happily and it also held as much vac as I could apply.
Forgot to add in first post, also did a sniff test for CO2 with an ebay kit and it didn’t activate that either?
Have covered 2k miles in it now. Reason I overhauled the cooling system as was blowing colder at idle and when I did the belts (first job) I found evidence of a decent leak from the water pump area. I can’t say for sure whether or not it bubbled before my intervention.
27th Feb 2020 3:23 pm
Discoveringcomfort
Member Since: 16 Sep 2015
Location: Berkshire
Posts: 637
I watched a test of a cheap chemical test, it did not show up the HG but it was noted that the water level was low in the tank like a Disco, when the level was increased to exclude the air gap it showed positive.Series 1 V8
Series 2 Hibrid V8
Discovery 3 HSE V8
27th Feb 2020 4:18 pm
Disko
Member Since: 19 Nov 2019
Location: Cambridge
Posts: 15
Interesting, will have a try of that. It wasn’t the ‘cheapest’ test available but as testing alongside other methods didn’t want to go crazy. Tried it on a glass of flat tonic water after and the fluid changed colour in about 30 seconds...
I’m fully prepared to move this one on if needs be but would like to have a smoking gun of some variety as it drives soooo well.
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