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MG MGF Technical - Coolant level warning - worthwhile?

OK - first question! - on our newly acquired '99V F.
It's done a genuine, documented 43k miles and has a full service history - including a massive full service (cambelt / tyres / Hydragas recharge) at Brown and Gammons last year.
However, there seems not to have been a head gasket failure (or upgraded HG as insurance) - so, going from a bomb-proof MX5 to an F as my partner's daily drive, I want to do all I can to mininise that "ticking time-bomb" feeling.
As an F enthusiast for many years (I had one of the first in early 1996) I'm well aware of warming-up precautions, bleeding the system, checking underfloor pipes, hoses, rad, coolant reservoir etc. regularly.

But I've just found that both Mike Satur and Brown & Gammons do a low coolant level kit for around 90 - which seems to consist of a replacement reservoir - presumably with integral float, and buzzer / light / wiring etc. B&G claim that low coolant level is the cause of "9 out of 10 head gasket failures".

Question is - Would this be the best 90 I could spend on the F for peace of mind? Anyone else fitted one? Any difference between the 2? (Mike's website currently shows "out of stock" - so someone must be buying them!)

Steve Clark

Hi Steve,
YES, yes and don't know.
I have had the B&G one for a couple of years and am very happy to recommend them - something very similar became a belated factory fit from about 04 models on. There is another kind called a Lolarm which is easier to fit and less money, but there have been reports....

The sensible thing to do is check the water level before a trip anyway, so for daily commuting the alarm is superfluous, although it might have a use for long distance travel.

I have the B&G version fitted which worked well for a couple of weeks but then started to sound when warm (water up to the mark in the reservoir but alarm still sounding). Consequently I have now disconnected the box of electronics until I have time to investigate a possible sticking sensor.

Peace of mind? Not for the couple of days I spent stopping imediately it went off in slow moving traffic with limited places to pull off the road.


Steve As you know I have had my car for a few weeks now and had considered exactly the same as yourself.

I am trying to find one from a donor vehicle of some decription but have so far not found a suitable donor however a weeks or so ago it could have paid huge dividends.

For some reason I borrowed the car off my wife for a week to take me to work. Fortunately I park it just outside my office and one afternoon as I walked outside I saw fluid under the car. Yep it was water and antifreeze. Investigating immediately I found that the bleed plug at the top corner of the radiator was leaking as the top had sheared off through overtightening. (not by myself I hasten to add) I think the garage who had done the headgasket before I got the car had just nipped it up a little too much. Had my wife been using the car she would not have noticed this water loss and thus problems may have occured. Must get a level sensor quickly
Bob (Robert) Midget Turbo

Yes, Yes, Yes I recomend having one fitted. I bought one of the first B&G ones and it paid for it's self within the first 5 weeks of fitting. No not HGF but a failed water pump, the warning went within seconds, so I filled up the reservoir and drove to my workshop keeping an eye on the temp gauge and listening for the beep. I did not fit the warning lamp and have found the SOUND loud enough even with a helmet on whilst racing.
Andrew W Regens

B&G fitted two years ago. It has done its job very well. The only time my F lost the cooling fluid -which can happen in seconds- the sensor immediately went off. Allows you to stop, call the AA and avoid further expensive damage.
JM Vega-P.

Fitted a loalarm to my car and it spotted the leaking inlet manifold gasket which was dropping the level only very very slowly but could have failed catastrophicaly if left, so was able to get it changed before it casued a head gasket failure. ( Although I did have a precautionary head gasket change at the same time as my car had 50k miles on it and is a 96 F on its original gasket )

I would not recommend a loalarm though they are hand made and a little to delicate for long term use. I would recommend the B&G as it is based on MG Rover components fitted to production TF's from 2005.

I now have a hybrid of Loalarm with MG Rover tank and sensor, the Loalarm sensor having fallen apart.

I'd recommend fitting one, I have had the B&G one for nearly 2 years, and it made me a lot less paranoid about coolant levels. It means you can get away with waiting for the radiator, coolant pipes and hoses etc to fail rather than replacing them in case they start leaking and cause HGF.

That said, my HGF (81K) happened gradually between oil and water and there was no associated massive water loss. But its the loss of coolant which writes off K series engines, and the low level sensor should prevent that.

I'll wave if I see another 75 LE in Southampton!


LE #1752, black with mulberry hood
P Davey

Totally agree with Pete Davey. I've had the B&G version for around 2 years, the paranoia's gone. The point is your engine may have a water leak from anything; once the level is too low, HGF/scrapped head/scrapped engine must occur through overheating which you won't know about. As I understand it, the water temp gauge sensor is on the RETURN line from the radiator! The level sensor tells you when the level is low, not when its too late, so the engine still has water; so alloy engine saved.
One thing. The B&G sensor is not actually failsafe. When the float drops it switches "on" as its normally off. If there should be a break in the wire to the tank the alarm won't sound. But the telltale start-up still beeps twice to say the system is working OK, which it isn't...
Recommend, every now and then, with ignition on, push the level sensing float down inside the tank for approx 15 seconds. Alarm should then sound. The delay is built in to allow for cornering.
Get the tank cap checked every service and carry a spare as they do fail.
Pete Tipping

I can't comment on the other types, but the B&G one is excellent with possibly the best fitting instructions I've ever seen. It worked faultlessly on my MGF. Checking the level before you drive off might be a good idea, but how many people would do it in the dark in the rain? In any case, there is so little reserve of coolant on these cars that a loss occurring while driving will swiftly "cook" the engine. The alarm will give you warning in time to pull over and hopefully prevent a major problem. Get one.
Mike Howlett

My B+G coolant alarm smart box packed up in August.I sent it back to them and that is the last I have heard of it.After several telephone calls,They said there was a mod coming out and that the smart box was on back order.

In the mean time ,I have modified my existing low coolant alarm to work just off the coolant sensor,it does bleep occasionally when I corner hard.

I have recently fitted the Rover coolant tank with low coolant alarm for two friends,I have used a bleeper from Maplins and 12v lamp,works fine and cheaper too!
simon connolly

Fitted a B&G coolant alarm virtually straight away after buying my Abingdon. Also at the time changed radiator for the improved Mike Satur one plus stainless underbody coolant pipes, also renewed all rubber hoses and changed old hose clips for decent stainless steel ones. Plus of course renewing the coolant.

Pease of mind with the coolant alarm but don't rely on it, still check the water level regularly visually.

Only thing not fitted yet is a PRT but will do that sonn as well.

S J Sibthorp


Don't have those on midgets...
Steve Clark


See attached picture.


simon connolly


So I'm guessing the T stands for thermostat.
Come on guys - help me out here.
Steve Clark


Go to this link.

simon connolly


I have a MGF K series fitted in my working London TX1 Taxi,so there was no point in buying this kit,so I went to a landrover dealer and just bought the remote thermostat only.I plumbed it in to my cooling circuit by using 28mm compression fittings ,including a 28mm tee piece, a couple of 90 degree fitting ,28mm copper pipe and 28mm gates flexi hoses from Halfords.I will find the part number for the thermostat,if you want it.

simon connolly

Dave where did you get the Rover tank and sensor from??
Bob (Robert) Midget Turbo

They're available from any X-part dealer, if you want to pay X-part prices! Alternatively, I think that they're fitted to all MG Rover cars from 2004 on ward (i.e. post face lift), so should also be available from salvage merchants.

B&G box of tricks is very good though - and well worth the money. I got one of the first, and it's been 100% reliable. Gone off a couple of times, just to remind me to top up the coolant a touch :o)

Buy one - it probably is one of the single best 'mods' available for our cars :o)

(I am not sure, but I suspect that Mike Satur retails the B&G coolant sensor - the two companies reciprocate by retailing each others products from time to time - and certainly no harm in that!)
Rob Bell

Rob I bought the parts from Rimmer Brothers they had them in stock.

Thanks for that Rob, and Dave how much did Rimmers charge you for the new bottle and sensor
Bob (Robert) Midget Turbo

Sorry Bob it was over a year ago so can't remember. They were pretty quick at mailing it out although I managed to burn out the first switch and had to get another! It was a panic at the time as we were preparing the car to go to the MGCC international event in Germany, where I had a rear hydrogas unit fail :-( Car came back in a big truck.

This thread was discussed between 04/11/2008 and 13/11/2008

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