Under bonnet steam

__chris__ · 2nd November 2012, 13:59

Forgive me if this has previously been covered elsewhere; have done a search and couldn't find a solution to this problem:

When driving along, particularly in slow stop/start traffic, the engine heats up quite quickly with the result that steam soon starts to appear from under the bonnet.

I've put the diagnostic mode on and can tell that it happens shortly after the temp. reaches 108. At this point I start to hear the faint sound of what appear to be water running along pipes and if I don't keep the car moving then steam starts to be generated. Popping the bonnet shows me that water is seemingly leaking from somewhere, hitting the engine block and producing the steam.

The problem is that I don't know where to start to look. It only happens once the temp. has reached 108 so I assume this is part of the key to solving the problem. The wettest area seems to be at the front, between the engine and the radiator. Is there a part of the cooling system there that only opens at this temperature?

The temp. needle in the car never moves above the halfway point and I'm wondering if there is air trapped in the system. I've read one post on the forum that the expansion tank ought to be raised up when refilling the system; can anyone confirm this?

Many thanks.

RPWC · 2nd November 2012, 14:05

There is a T piece in the cooling system which can break,and leak coolant,I'm not 100% sure,but I think it's on the left of the engine,as you look at it from the front of the car

__chris__ · 2nd November 2012, 14:08

Quote:

Originally Posted by RPWC

There is a T piece in the cooling system which can break,and leak coolant,

Thanks.
I've seen the photos of this and the replacement ones that someone is manufacturing.
Does this only come into play at the higher temperatures then ?

RPWC · 2nd November 2012, 14:15

TBH mate,I haven't a clue,not clued up on the petrol engines,been running a diesel for 3 years,so out of touch with petrols. There are p,entry folk on here though,that will advise you better,just watch this space.

greendriver · 2nd November 2012, 14:19

Your fan should switch on at about 104-5c. Have you checked the coolant level, it needs to be topped up regularly if leaking, & the leak found.

chipsceola · 2nd November 2012, 14:27

The only time my 1.8T had steam under the bonnet it overheated and blew the head gasket, that was due to a leak in the small hose to turbo off the T piece, when AA man refilled system improper bleeding, air lock, over heat and HGF all in 4 miles in a 30mph zone!

Refill header tank when cold, fill to level just above fins, then recheck level daily to determine if you have leak, if you do, fix as matter of urgency or suffer HGF in double quick time!
Chips

NB these car have a tendency to leak coolant on cooling down cycle, most often noticed with short trips and therefore lots of cooling down for miles covered. Often no coolant loss with a long journey as leakage doesn't occur while driving.

Steve916 · 2nd November 2012, 14:30

As above, the fan should've kicked in way before it gets to that temp.
Have you checked the fan works on all speeds?

stugee · 2nd November 2012, 14:34

Mine had exactly the same problem. It happened twice 2 weeks ago and hasn't happened again. I couldn't find where it was coming from either

I'm keeping an eye on the coolant level and it hasn't dropped, very strange!

Please keep this thread updated if you manage to find the fault and/or rectify it!

Cheers

kaiser · 2nd November 2012, 14:47

It has been covered, many times.
Here is one from 2008!

http://www.the75andztclub.co.uk/foru...hlight=t-piece

__chris__ · 2nd November 2012, 15:14

Quote:

Originally Posted by chipsceola

Refill header tank when cold, fill to level just above fins,

Thanks - that might well be the start of the problem. I'm new to the car and have been relying on the illustration in the owner's handbook (page 194) which shows a small tab marked 'max' and 'min'. I've just been covering the 'max' mark and this is at the bottom of the header tank, nowhere near the top of the fins.

I'll order one of Kaiser's t-pieces to be safe, too.

How do I check that the fan's working? Without wanting to sound too thick, do I need to take of the front bumper to see it as it doesn't appear to be visible if I just pop the bonnet?

Your ongoing help is much appreciated.

Chris.

2nd November 2012, 13:59	#1
__chris__ Avid contributor 2003 MG ZT 190+,(2005 Facelift R75 1.8T SE Conny now consigned to be a donor car) Join Date: Sep 2012 Location: Sidcup Posts: 149 Thanks: 34 Thanked 4 Times in 4 Posts	Under bonnet steam Forgive me if this has previously been covered elsewhere; have done a search and couldn't find a solution to this problem: When driving along, particularly in slow stop/start traffic, the engine heats up quite quickly with the result that steam soon starts to appear from under the bonnet. I've put the diagnostic mode on and can tell that it happens shortly after the temp. reaches 108. At this point I start to hear the faint sound of what appear to be water running along pipes and if I don't keep the car moving then steam starts to be generated. Popping the bonnet shows me that water is seemingly leaking from somewhere, hitting the engine block and producing the steam. The problem is that I don't know where to start to look. It only happens once the temp. has reached 108 so I assume this is part of the key to solving the problem. The wettest area seems to be at the front, between the engine and the radiator. Is there a part of the cooling system there that only opens at this temperature? The temp. needle in the car never moves above the halfway point and I'm wondering if there is air trapped in the system. I've read one post on the forum that the expansion tank ought to be raised up when refilling the system; can anyone confirm this? Many thanks.

2nd November 2012, 14:05	#2
RPWC This is my second home 75 model car Join Date: Apr 2011 Location: Newcastle upon Tyne Posts: 20,177 Thanks: 4,008 Thanked 5,083 Times in 3,114 Posts	There is a T piece in the cooling system which can break,and leak coolant,I'm not 100% sure,but I think it's on the left of the engine,as you look at it from the front of the car __________________ Cheers. Rich…

2nd November 2012, 14:15	#4
RPWC This is my second home 75 model car Join Date: Apr 2011 Location: Newcastle upon Tyne Posts: 20,177 Thanks: 4,008 Thanked 5,083 Times in 3,114 Posts	TBH mate,I haven't a clue,not clued up on the petrol engines,been running a diesel for 3 years,so out of touch with petrols. There are p,entry folk on here though,that will advise you better,just watch this space. __________________ Cheers. Rich…

2nd November 2012, 14:19	#5
greendriver This is my second home MG ZTT 180 in Poseidon Join Date: Feb 2011 Location: Croydon Posts: 3,745 Thanks: 44 Thanked 86 Times in 75 Posts	Your fan should switch on at about 104-5c. Have you checked the coolant level, it needs to be topped up regularly if leaking, & the leak found. __________________ *None of my troubles are Rover*

2nd November 2012, 14:27	#6
chipsceola This is my second home Jaguar XF 3.0D Join Date: Nov 2010 Location: Southampton Posts: 4,364 Thanks: 119 Thanked 509 Times in 426 Posts	The only time my 1.8T had steam under the bonnet it overheated and blew the head gasket, that was due to a leak in the small hose to turbo off the T piece, when AA man refilled system improper bleeding, air lock, over heat and HGF all in 4 miles in a 30mph zone! Refill header tank when cold, fill to level just above fins, then recheck level daily to determine if you have leak, if you do, fix as matter of urgency or suffer HGF in double quick time! Chips NB these car have a tendency to leak coolant on cooling down cycle, most often noticed with short trips and therefore lots of cooling down for miles covered. Often no coolant loss with a long journey as leakage doesn't occur while driving. Last edited by chipsceola; 2nd November 2012 at 14:31.. Reason: NB added

2nd November 2012, 14:30	#7
Steve916 This is my second home Rover 75 1.8 Connoisseur SE and a Ford S-Max Titanium Join Date: Jan 2012 Location: Huntingdon Posts: 3,756 Thanks: 70 Thanked 31 Times in 27 Posts	As above, the fan should've kicked in way before it gets to that temp. Have you checked the fan works on all speeds? __________________ Mods so far: Plenums, bonnet release mod, handbrake compensator (arctic), rear parking sensors, coolant level sensor (Vindaloo), DRL's, Fan resistor upgrade ( Jules), Marmite lighting, Auto dimming rear view mirror, twin horns, fog lights, real walnut dash, walnut gear knob, Sean DD unit with DVB-T, message centre ipk, electric sun blind, auto opening boot lid, walnut steering wheel, electric seats Link to my Auto Boot Lift Mod http://www.the75andztclub.co.uk/foru...d.php?t=114273

2nd November 2012, 14:34	#8
stugee Avid contributor MG ZT+ 1.8T Join Date: Oct 2012 Location: West Lothian Posts: 249 Thanks: 0 Thanked 1 Time in 1 Post	Mine had exactly the same problem. It happened twice 2 weeks ago and hasn't happened again. I couldn't find where it was coming from either I'm keeping an eye on the coolant level and it hasn't dropped, very strange! Please keep this thread updated if you manage to find the fault and/or rectify it! Cheers __________________ "Understeer" is when you hit the wall with the front of the car. "Oversteer" is when you hit the wall with the rear of the car. "Horsepower" is how fast you hit the wall. "Torque" is how far you take the wall with you.

2nd November 2012, 14:47	#9
kaiser This is my second home 75 Tourer 2.5 Auto, 1.8T, 75V8ZT Join Date: Jun 2007 Location: Johannesburg ZA Posts: 6,200 Thanks: 1 Thanked 859 Times in 613 Posts	It has been covered, many times. Here is one from 2008! http://www.the75andztclub.co.uk/foru...hlight=t-piece