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MG MGF Technical - coolant loss,need help

Hi guys,i know this is a thread title that most of you hates,but i need some advice and help.I am the owner of 1998 VVC, which is very well looked after, and never pushed hard.(a weekend car at only 15000 km)When i was driving tonight,the engine temp level started to rise.It rose one bar above the normal.5 minutes later i stopped to check it.Just when i was parking i noticed on the right wing mirror steam coming out of the engine.Checked the coolant and it was nearly boiling.It rose to nearly the top of the coolant cap and there was coolant on the cap, some was spilt on the engine(on the cover where it says VVC), and coolant coming out of the water.There was also a smell but it may be the coolant i guess.This does not look like a loose hose to me, as the hoses were checked and tightened 4-5 weeks ago.Anyways, i waited for 20 minutes,and drove back to home which was 20 km away.Nothing abnormal happened on the way.I waited 5 minutes for the engine to cool down and checked the coolant level.Before the incident,it was at max level, now the coolant tank is half full.What do you think is wrong? If the head gasket is blown, how can i know it? Also i know on the trackdays many people experienced stuff like this and all were not the hgf.Could it be because of the hot weather? Nearly 35C.Many thanks.
Phantom

I think that you had too much coolant in your reservoir to start with. If you say after the incident the coolant was half full then it must have been full to the cap before and when it gets too hot it boils and will automatically try to escape through the cap because that is the neareast it can go to. My coolant level is at max when its half full in the reservoir so it has some room to boil. Hope it makes sense. So make sure it's not as full as a new coke bottle otherwise it will spill again ;-)

Jorg
Jorg

The level of coolant goes up and down depending on engine temp. It's supposed to be filled to the seam line on the reservoir tank when cold, as Jorg says, superflous coolant will try to escape when hot.
Dot

Phantom, I think it's not HGF, which is a good news. Your coolant should be always half filled where the seam is running.

How about getting a new coolant cap with a white dot on the top of the cap? It's cheap and should fix any future problems.

Good luck!

Regards,
Hanah
Hanah Kim

Thanks guys,but the thing is,the coolant level when cold is at the max.(at the level where it says max on the tank not that the tank is full,somehow the max level is shown on the interrior side of the tank :)).Again i was suspicious that something was wrong so i bought a new cap two weeks ago and made sure that it was properly fitted.Anyway i went for a drive today for about 15 km,(no coolant on the ground where it is parked) normal traffic,engine was hotter than usual and the side fan was on more than normal(not sure about the front one).This is not something new by the way,for the last 3-4 rides it gets extremely hot, when i go for a coolant check,i can feel the it is much hotter than usual.Also after i stopped today,some more coolant was on the plastic stuff around the coolant tank,and some nearby.However none on the ground,after i parked.What do you think is the problem? Tomorrow is monday,and first thing on my list is a visit to the dealer.Hope all will be sorted.
Phantom

Posible that:
Broken water pump(does the radiator get hot at all?- does the heater matrix get hot?)
Faulty fan (check fuses and for fan spining)
Faulty temp sensor ( there are two, I think they are the same spec - one goes to the gauge, the other toi the MEMS - swap the connectors over and see if it cures the problem and buggers the gauge)
Sticking Thermostat (does the radiator get hot at all?)
faulty coolent cap (oh and don't touch it whilst at all hot or the system will boil!)
Air lock in the system (does the radiator get hot)
HGF Water/combustion mode (does the coolant smell of petrol?)

HTH

Will
Will Munns

>faulty coolent cap

FYI, installed the third spare of this sh*t part today to my 2 years old car (50k km now on the clock).

IMO after having spotted for now 4 weeks how the coolant level rose and went down under temperature and after about half a liter loss back to the standard maximum mark. (Lots of stains around the expansion tank)

Coolant was topped up by mad dealer at the 40k km Service about 2cm above the maximum seam. I let it there to see what will happen further on ;)

Theory:
Space for expanding coolant is to less then. Coolant meets the cap and some drops always pass through if the engines is hot.
Dunno whether possible from dry derivates or what or just from the high temperure coolant. But I believe this damages the cap within the next 5k km.

Any thoughts ?
I'll cut the broken cap with the small hacksaw soon in any way. Got now one old without the white dot and one newer with that dot (to get comparisons of the design).

Dieter
Dieter Koennecke

Went to the service yesterday and they did the pressure tests and everything is ok.And then they found out that one of the fans was not working because of a faulty fuse.(phew)I feel much happier now that it is all sorted out and no hgf.However i am still worried that i might have weakened the head gasket and as i intend to keep the car for a looong time, i try to keep it in the best shape.What annoys me recently are the interrior rattles.Has anyone got a cure for this?
Phantom

This thread was discussed between 03/08/2002 and 06/08/2002

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