Go Back   The 75 and ZT Owners Club Forums > The 75 and ZT Owners Club Forums > Technical Help Forum
Register FAQ Image Gallery Members List Calendar Mark Forums Read
Notices

Reply
 
Thread Tools Display Modes
Old 13th February 2019, 10:40   #21
Simon W
This is my second home
 
Rover 75 2.0 Litre Club Saloon

Join Date: Nov 2006
Location: S
Posts: 3,280
Thanks: 38
Thanked 50 Times in 47 Posts
Default

Update - Residual Pressure Test

TC - I redid the test late last night (i.e. ran the engine for 30 mins).

I've just taken the tank cap off and there was a very slight hiss (engine completely cold).
Simon W is offline   Reply With Quote
Old 14th February 2019, 16:14   #22
T-Cut
This is my second home
 
Rover75 and Mreg Corsa.

Join Date: Nov 2006
Location: Sumweer onat mote o'dust (Sagin)
Posts: 21,751
Thanks: 341
Thanked 3,660 Times in 2,924 Posts
Default

Quote:
Originally Posted by Simon W View Post
Update - Residual Pressure Test
TC - I redid the test late last night (i.e. ran the engine for 30 mins).
I've just taken the tank cap off and there was a very slight hiss (engine completely cold).

A very faint sigh can be normal, but a sound like a pop bottle hiss would be concering. Can you repeat this test, but revving the engine to 3000 for 30 secconds every five minutes or so? Of course you musn't release the cap for 6-8 hours or till next day.



Quote:
On mine, there's a definite point where something suddenly changes and the coolant gushes out of the expansion tank at an alarming rate. It'll flood the complete tank rim very fast - much faster than I can turn the engine off.

I'd suggest you do the textbook bleed/top up and then repeat this test. The coolant shouldn't become pressurised in this manner unless it's overheating/airlocked/pumped (exhaust).


TC
T-Cut is offline   Reply With Quote
Old 14th February 2019, 17:38   #23
Simon W
This is my second home
 
Rover 75 2.0 Litre Club Saloon

Join Date: Nov 2006
Location: S
Posts: 3,280
Thanks: 38
Thanked 50 Times in 47 Posts
Default

Quote:
Originally Posted by T-Cut View Post
A very faint sigh can be normal, but a sound like a pop bottle hiss would be concering. Can you repeat this test, but revving the engine to 3000 for 30 secconds every five minutes or so? Of course you musn't release the cap for 6-8 hours or till next day.

TC
It's more of a sigh than a bottle hiss. Anyway, I've just done the above test (engine to 3000rpm etc.) so I'll take the cap off tomorrow and see what it does this time.


Quote:
Originally Posted by T-Cut View Post
I'd suggest you do the textbook bleed/top up and then repeat this test. The coolant shouldn't become pressurised in this manner unless it's overheating/airlocked/pumped (exhaust).
TC
Ok, I'll do a bleed/top up after seeing (hearing) what happens when I take the cap off tomorrow.

NB. If I turn the engine fan off (via Demist button) or switch the engine off I can hear some faint gurgling going on behind the centre console.
Simon W is offline   Reply With Quote
Old 14th February 2019, 20:36   #24
T-Cut
This is my second home
 
Rover75 and Mreg Corsa.

Join Date: Nov 2006
Location: Sumweer onat mote o'dust (Sagin)
Posts: 21,751
Thanks: 341
Thanked 3,660 Times in 2,924 Posts
Default

Quote:
Originally Posted by Simon W View Post
- - - - I can hear some faint gurgling going on behind the centre console.

Gurgling means air bubbles. Bleeding and topup essential.



TC
T-Cut is offline   Reply With Quote
Old 15th February 2019, 15:01   #25
Simon W
This is my second home
 
Rover 75 2.0 Litre Club Saloon

Join Date: Nov 2006
Location: S
Posts: 3,280
Thanks: 38
Thanked 50 Times in 47 Posts
Default

Quote:
Originally Posted by T-Cut View Post
Gurgling means air bubbles. Bleeding and topup essential.

TC
Ok TC - will do (bogged down with headlining removal at the moment - the usual nightmare with trim fixings etc. )

BTW, no hiss at all from the tank cap this morning.
Simon W is offline   Reply With Quote
Old 16th February 2019, 23:23   #26
Copilot
Regular poster
 
Rover 75 Saloon

Join Date: Jun 2018
Location: Odense
Posts: 70
Thanks: 60
Thanked 31 Times in 11 Posts
Default

Quote:
Originally Posted by Simon W View Post
(...)Pedro - if you put the 400ml of coolant back in so that the level is on the MAX line (measured at cold), then run the engine up to hot and wait (with the car standing still), is there a point when it suddenly starts gushing out of the expansion tank? Or does it only do it when you're driving the car out on the road?

On mine, there's a definite point where something suddenly changes and the coolant gushes out of the expansion tank at an alarming rate. It'll flood the complete tank rim very fast - much faster than I can turn the engine off. (...)
On mine, it only happens when I rev it up for some time ( I would say 5/7 secs.) after the engine is warm.
I also did a test idling until the coolant reaches 87/90º and nothing happens.

I'm suspecting the problem could be the cap or the O-rings. I will give a try and see what happens with the new one

I agree with T-cut, in your case Simon, that gurgling you mention definitely means air locked in the cooling system. Mine doesn't have that noise.
If I was you I would try bleeding the system and see if it can solve the problem.

Anyway I will report the situation in mine as soon as the cap arrives.
__________________
[SIGPIC][/SIGPIC]
Copilot is offline   Reply With Quote
Old 4th July 2019, 14:58   #27
Blink
Posted a thing or two
 
Blink's Avatar
 
Rover 75 Saloon

Join Date: Apr 2019
Location: Under the car
Posts: 1,840
Thanks: 210
Thanked 244 Times in 221 Posts
Default

Quote:
Originally Posted by Copilot View Post
.... Anyway I will report the situation in mine as soon as the cap arrives.
Pedro - did the new cap solve the problem?
Blink is offline   Reply With Quote
Old 5th July 2019, 01:16   #28
Copilot
Regular poster
 
Rover 75 Saloon

Join Date: Jun 2018
Location: Odense
Posts: 70
Thanks: 60
Thanked 31 Times in 11 Posts
Default

Quote:
Originally Posted by Blink View Post
Pedro - did the new cap solve the problem?
Simon I ended up replacing just the O-rings once I've changed the thermostat and after that, I discovered there was an airlock in the cooling system, mainly because I'm dum and I didn't bleed by the book.

So the spilling coolant problem in my case is almost certainly related to airlock.

Enviado do meu Redmi Note 6 Pro através do Tapatalk
__________________
[SIGPIC][/SIGPIC]
Copilot is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT. The time now is 00:12.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Copyright © 2006-2023, The Rover 75 & MG ZT Owners Club Ltd