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MG MGA - Engine Heater, frost protection.

Hello MGA people.

Just wondering if anybody out there has used a device to heat the engine oil to protect against frost, and to allow for better starting in cold weather.

Took about 10-15mins of gentle starting to get going at the w/e. When i have the chance, I always try to take her out for a run if I can, even if it's seriously parky

We have antifreeze in the water, battery is on trickle charge/conditioner and is fine.

car is in storage which is dry but very cold in winter, not practical to heat the whole space. I could put a small tubular heater under the sump, but most of the heat will be lost.

I see oil dipstick heaters on the web but they are all 120V. seems like a sensible idea as, if the oil is kept warmish, the whole block will also be warm.

Incidentally when out at the w/e wipers stopped working along with brake lights, this turned out to be the fuse, it had moved in the holder, slipped of the end cap, some of the roads are very rough, a quick push back in place, and all was well.

ideas, comments, advice on the heater thing please.

Early RHD 1500

laurence dunnett

Living in Alaska, I have engine heaters installed on my daily drivers, but not on the MGs. Just heating the oil will not keep the whole block warm, but it can help, especially if the cold temperatures are not extreme. For starting under sustained temperatures below freezing, a coolant heater is more beneficial, if you are only going to have one heater. On my daily rigs, I have a coolant heater, battery heater, oil pan heater, and transmission heater. That's likely overkill for your requirements.

I would not use a heater that is inserted through the dipstick. Here, we use a heating pad that is attached to the underside of the sump using RTV adhesive. It's fully reversible, although in practice you aren't going to remove it easily (not that you'd really want to if you are operating your car in the winter).

The above heater is typical of the type. To install, first get the bottom of the sump as clean as possible. There is no need to remove paint unless it is flaking off, but there can be no trace of oil or grime. Spread a thin layer of hi-temp "ultra copper" RTV on the upper surface of the pad, and stick it to the sump. Then hold it in place with several pieces of duct tape, of sufficient length to wrap up the side, and hold the pad in place securely. You will want to have also cleaned the sides of the sump so the tape will stick. Get the tape tight, and there is no such thing as too much tape.

Route the power cord to suit, and once the RTV has cured, it is ready for use. You can leave the duct tape in place if you want, but removing it will leave a neater appearance. Once the RTV is fully cured, it is not necessary. I have installed many of these pads in this manner, and never had one come off.

D Rawlins

What do you call cold? Have had wonderful results with magnetic sump heaters. Warms the sump, oil and a little heat conducts into the block. Have used them on diesel engines to -40C.

Just don't ask where to get them in the UK.

Was writing same time as Del. He would be the expert. It gets way colder where he is than where I am.
C.R. Tyrell

Dip stick heaters are almost useless, too small and not heating enough of the oil. Flat heater on bottom of the sump (oil pan heater) can heat the oil well enough, but the upper engine, especially the cylinder head and carburetors, will remain cold.

The most effective engine heater is the core plug heater. It is a resistance col-rod heater to be installed in place of the center core plug (right side of the block in the MGA/MGB engines).

1500 watts - 12.5 amps @ 120-volts. Should also be available in 240-volt version, about 6-amps.

1500 watts may be overkill for the small MG engines. 750 watts may be adequate. You can hook it up with a clock timer to switch on maybe two hours before you want to drive the car. Heated water will warm up the whole engine for easy quick start, fast warm up after start, and maybe even have the heater working soon after start up.

Search the net for "core plug heater"

Barney Gaylord

The item Barney mentioned is ideal and very cheap - if you live in the States. Shipping one to the UK and then being charged VAT & Import Duty on landing bumps the price up. In the UK, Kenlowe do a pre-heater but is obscenely expensive at over 350!! We could all chip together and buy a box of 10 "in-line" heaters from China for about $160!! On these units you just cut a heater hose and fit the heater. It has a small impeller which circulates the water. The same principal as the Kenlowe.

Colin Manley


An MGA shouldn't need a heater in the UK to get acceptable starting times. I would suggest you have a problem somewhere, choke would seem the first suspect.

The reason I say this is that for my first 5 years of MGA ownership I did 30k miles a year living in London, mainly Birmingham and then Edinburgh and I never had starting times anything like yours (well unless I had some specific issue!).

Take this as encouragement that your solution is easier than you think.

Paul Dean

Hi all, I am in the UK, so not dealing with really cold as you guys are in the US. we can expect a max of -10C

Car starts on the button when it's not too cold.

Will take a look at the choke next next time I get a chance.
I'll also try a heater underneath the sump for a while before starting.

It's an original early GB engine and bits, so may need some work.
Once going, and warmed up it goes really well, and is very reliable.

Thanks for all the info.


laurence dunnett

I agree with Paul, it sounds like the choke is not adjusted correctly. Very common problem. Once it is properly set, the car should start instantly, whatever the temperature (in the southern UK at least!)

The heaters are still a very good idea as they reduce the wear an engine suffers when started from cold.
Neil MG

> The heaters are still a very good idea as they reduce
> the wear an engine suffers when started from cold.

Yes, this. A vehicle which has been plugged in for a couple hours prior to starting in freezing temperatures will achieve normal oil pressure more quickly than one which has not. It's worth noting that a modern fuel injected engine in good condition will almost always start at temperatures as low as 40 below zero without any pre-heat, but that doesn't make it a good idea. Been there, done, that, forgot to plug in, and had to get to class.

And as Barney noted, it also reduces the amount of time it takes for the heater to begin producing usable amounts of heat. That can be an important consideration.

I have vehicles with both the "freeze plug" style heater, and the circulating heater which tees into a heater hose on one end, and the engine drain on the other. Both types work fine.

D Rawlins

I agree about the secondary reason to put an electric heater of some kind in particularly in very cold climates. In the 1950s my father used to leave a mains inspection light on under the bonnet on cold nights in the the then rather old prewar Morris and Wolsley he had. Inspired by this thread I thought it was about time I started my now recently rebuilt 1800 MGA and it started in about 10 secs at about 3C. I have sometimes over winters, as an extra security measure, swapped 2 plug leads, and then in the still cool Spring I have forgotten and succeeded in starting the engine on 2 cylinders, not recommended as it also backfires on the other 2 cylinders, but it does show how easy 1500 MGAs should start.

Last summer I went to an outdoor museum at Ironbridge in England and they have a working model of Richard Tretherick's 1804 steam locomotive which was the first in the world to pull a train, see link below.

The relevance to this thread is that it had a caravan style electric plug. When I asked about this the guys who were operating this reluctantly admitted they had a domestic immersion heater in the boiler to speed up start up in the morning! Tretherick certainly didn't have that option in 1804.

Paul Dean

This thread was discussed between 02/02/2015 and 04/02/2015

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