hgf maybe

Steve42 · 16th January 2020, 06:32

hi guys,
my old mk1 v6 is pushing out more coolant than I can put in out of the cap. its been forced out by bubbles.
have no mayo in the cap or water in the oil . seems ok till its warmed up.
so far had new stat and pipes new header tank cap.
car when running seems fine. no miss fire, revs as they should be.no water in the v. mpg has gone down by about 1 or 2 mpg .
holding a lot of pressure in the coolant system.
temp was always 93c since the new stat and sender unit runs at 88c till its starts to over heat. when it starts to go does not come down.
fan works ok . kicks in at 100 but temp does not come down. been as high as 115c but manged to pull over and let it cool down. never got to the killer 120c.
one place local has said its hgf . but most garages round me will not touch it or just want to change the engine. engine only has 74 thousand on the clock.
any pointers .

thanks
steve

SD1too · 16th January 2020, 07:45

Start by draining and refilling the cooling system following exactly the MG Rover procedure for the KV6. It's highly likely that you have an air lock. Ignore misguided guesswork involving head gaskets and replacement engines.

Simon

Steve42 · 16th January 2020, 07:56

It's the old story . It's a rover must be hgf .
I don't think it is. But the pressure is coming from some place.
It's high enough to kick the cap in to releasing it.

SD1too · 16th January 2020, 08:20

Quote:

Originally Posted by Steve42

But the pressure is coming from some place.

An air lock Steve. Other members have been on this journey from disbelief to heartfelt joy.

Simon

thanos.m · 16th January 2020, 10:35

I had a similar issue when I bought my last 75 v6 it was puking all its coolant out and couldn't get it to fill up a full drain, refill and bleed by MGR procedure with the expansion tank raised up etc. Fixed it and didn't have any issues ever since. I did think it was a hgf as well because I had mayo but it turned out it was just the short journeys that cause it

Steve42 · 23rd January 2020, 13:52

well done the refill was fine when cold but soon as all was fitted back hit 93 and just forced all the water back out.
also found out that I have more oil in the air pipe from the air filter than in the sump. not a small amount but I could pour it out .
not looking good.

T-Cut · 23rd January 2020, 15:41

Quote:

Originally Posted by Steve42

- - - holding a lot of pressure in the coolant system.

Holding it for how long? Even when stone cold?

With air locking, the system pressure will rise faster than without and may well eject some coolant from the cap. However the pressure will drop back to 'zero' when the system cools back to ambient. If the coolant level is checked, then you establish ambient pressure in the system. After running the engine under driving conditions, the pressure will again rise, but should drop back to ambient ('zero') when it fully cools down. Any significant pressure remaining at that point is not good.

You could try the cold pressurisation test for exhaust gas by running the stone cold engine at high revs for a minute or so, then stop the engine and open the cap. No significant pressure should be released since the system hasn't warmed up.

TC

Steve42 · 23rd January 2020, 16:59

Hi all new cap has been fitted. In fact has had two new ones. Plus a old one off a v6.
As for pressure it holds it for a least two days.
New thermostat and pipe work and sender unit.
No external leaks
Only forcing coolant out when it hits from 90 to 100c its seems to change from day to day.but always I would say after the thermostat has fully opened.
Fan working.
Mpg has dropped from around 23 to 21 ish .
Engine sounds and running ok as in no miss fires.
Starts up first time.
No mayo in the cap
Tick over is normal.
3 garages have said the same as in hgf.but that would.
None will touch it or it's over a grand.then if more is found could be a new engine.

16th January 2020, 06:32	#1
Steve42 I really should get out more....... mg 190+ Join Date: Feb 2013 Location: Bedworth Posts: 2,267 Thanks: 191 Thanked 368 Times in 248 Posts	hgf maybe hi guys, my old mk1 v6 is pushing out more coolant than I can put in out of the cap. its been forced out by bubbles. have no mayo in the cap or water in the oil . seems ok till its warmed up. so far had new stat and pipes new header tank cap. car when running seems fine. no miss fire, revs as they should be.no water in the v. mpg has gone down by about 1 or 2 mpg . holding a lot of pressure in the coolant system. temp was always 93c since the new stat and sender unit runs at 88c till its starts to over heat. when it starts to go does not come down. fan works ok . kicks in at 100 but temp does not come down. been as high as 115c but manged to pull over and let it cool down. never got to the killer 120c. one place local has said its hgf . but most garages round me will not touch it or just want to change the engine. engine only has 74 thousand on the clock. any pointers . thanks steve

16th January 2020, 07:45	#2
SD1too Doesn't do things by halves Rover 75 2.5 Connoisseur Auto (1999) Dealer launch model. Join Date: Mar 2007 Location: Former Middlesex Posts: 20,391 Thanks: 1,587 Thanked 3,749 Times in 3,181 Posts	Start by draining and refilling the cooling system following exactly the MG Rover procedure for the KV6. It's highly likely that you have an air lock. Ignore misguided guesswork involving head gaskets and replacement engines. Simon __________________ "Whatever is rightly done, however humble, is noble." Sir Henry Royce.

16th January 2020, 10:35	#5
thanos.m Avid contributor Rover 75 saloon Join Date: May 2019 Location: West Sussex Posts: 224 Thanks: 54 Thanked 41 Times in 26 Posts	I had a similar issue when I bought my last 75 v6 it was puking all its coolant out and couldn't get it to fill up a full drain, refill and bleed by MGR procedure with the expansion tank raised up etc. Fixed it and didn't have any issues ever since. I did think it was a hgf as well because I had mayo but it turned out it was just the short journeys that cause it Last edited by thanos.m; 16th January 2020 at 12:01..

23rd January 2020, 13:52	#6
Steve42 I really should get out more....... mg 190+ Join Date: Feb 2013 Location: Bedworth Posts: 2,267 Thanks: 191 Thanked 368 Times in 248 Posts	update well done the refill was fine when cold but soon as all was fitted back hit 93 and just forced all the water back out. also found out that I have more oil in the air pipe from the air filter than in the sump. not a small amount but I could pour it out . not looking good.

16th January 2020, 07:56	#3
Steve42 I really should get out more....... mg 190+ Join Date: Feb 2013 Location: Bedworth Posts: 2,267 Thanks: 191 Thanked 368 Times in 248 Posts	It's the old story . It's a rover must be hgf . I don't think it is. But the pressure is coming from some place. It's high enough to kick the cap in to releasing it.

23rd January 2020, 16:59	#8
Steve42 I really should get out more....... mg 190+ Join Date: Feb 2013 Location: Bedworth Posts: 2,267 Thanks: 191 Thanked 368 Times in 248 Posts	Hi all new cap has been fitted. In fact has had two new ones. Plus a old one off a v6. As for pressure it holds it for a least two days. New thermostat and pipe work and sender unit. No external leaks Only forcing coolant out when it hits from 90 to 100c its seems to change from day to day.but always I would say after the thermostat has fully opened. Fan working. Mpg has dropped from around 23 to 21 ish . Engine sounds and running ok as in no miss fires. Starts up first time. No mayo in the cap Tick over is normal. 3 garages have said the same as in hgf.but that would. None will touch it or it's over a grand.then if more is found could be a new engine.