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MG MGF Technical - water loss

Driving to work this morning, I noticed the heater was blowing cold air. Being a very cold morning, ignored it at fast, half way to work, stopped at traffic light notice temperature guage going up. Switched on the fan to cool the engine down, after a few miles heater started blowing hot. Got to work and checked water collant bottle late morning, to my shock noticed it was very very low. Filled it up, started engine, temperature guage went up after 5 minutes, still blowing cold air. Any ideas lads.
Jeanne Dyson

Sounds like an airlock to me.

The heater is a very simple affair, it consists of a fan that blows air over a small radiator (matrix). If there is no heat coming from the system, then it suggests that there is no hot water in the matrix, this coupled with your description of a lack of coolant rings true to me.

When you say 'very, very low' do you mean 'empty expansion tank?' I ask because if this happens then there is a very good chance that air has got into the system.

The main issue here is not the heater blowing cold, that is a symptom rather than the problem. The problem is that the heater pipework is a spur off of the main cooling system, and if you have little / no water in the heating system then there is a very strong liklihood that you also have a similar situation with the engine cooling system.

My advice is to be very, very careful. Get the car looked at ASAP and try not to drive it if at all possible.

It sounds to me like you have at the least a coolant leak (which could be something as simple as a failed expansion tank cap, or something as expensive as HGF). Driving it around with low coolant / air in the system could provoke a Head Gasket Failure and you don't want one of those just before Christmas (or any time for that matter).

Good luck

SF
Scarlet Fever

Do you think I should replace the radiator, I'v been guoted a price of £85.00. The leak seems to be coming from the front end of the car. How long do radiators last, any ideas.
Jeanne Dyson

Jeanne,

Others with more experience of leaky MGFs will be along soon, but ...

the radiator on the F has been known (not quite prone) to corrode the fins away and eventually hole out and leak.

also the metal coolant pipes from radiator (at front) to engine (at back) go the length of the car under a cover plate. These also can corrode with time.

I've seen mention on hear of both pipes and rad failing anywhere from 5 years onwards.
JohnP

Hi Paul, thanks for your quick advise, my car is R reg over 7 years old. So maybe its time for a new one. Last year my car engine blew up on me, had to have a second hand engine put in as the dealership had run out of engines. Labour was very expensive.
Jeanne Dyson

>> Do you think I should replace the radiator, I'v been guoted a price of £85.00. The leak seems to be coming from the front end of the car. How long do radiators last, any ideas <<

Depends on where the leak is coming from.

It is true that radiators tend to be on the way out by year 5, so you are right to suspect it, however it may be OK, you should have it inspected at any rate.

If you have a coolant leak coming from the front of the a 5 year old + F, here are the things to check:

1 ) Radiator bleed screw.
This is a plastic bolt that screws into the top of the radiator. It provides a seal by the head clamping down on a rubber washer, because the bolt is plastic, if it is overtightened (by a grease monkey during a coolant change for instance) the head can shear resulting in a leak. Check this first because a) it is a common failure, b) it is dirt cheap to replace and c) it is easy to spot (open bonnet, look as bolt head through the square opening in the slam panel).

2 ) Radiator.
Original F rads are brass and consists of a number of horizontal pipes to carry coolant, with vertical cooling fins between them, all housed in a frame. At around 5 years, the radiator will exhibit some corrosion, normally in the bottom left hand corner. Because the radiator is housed in it's own enclosure it is difficult to inspect, but a torch held behind the radiator whilst looking through the lower grille is a reasonable way to do so. You should at least be able to tell is there are fins missing this way. You can also do this by feel, run your fingers lightly over the radiator surface (when the car is cold!) and feel for any fins breaking away. If it is gone, replace with either a TF one (it is aluminium) or one of Mike Satur's uprated ones (also aluminium). Mike's one also has the added advantage of curing the bleed screw issue (it's bleed screw is metal).

3 ) Hoses.
Hoses are pretty rubust here, but check the spring clips where the hoses join the radiator and the underbody coolant pipes. The can relax / corrode over time causing leaks.

4 ) Underbody coolant pipes.
These also corrode, but usually from the inside out. Mike Satur does aluminium replacements.

Hope this helps

SF
Scarlet Fever

My P Reg needed a new radiator earlier this year (after ~80k miles and six months of my local MGR dealer telling me they didn't know where my coolant was going). The price you've been quoted looks okay and - as others have said many times - you don't want to be left with no coolant in the engine!
Steve Madden

This thread was discussed on 21/12/2004

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