The Fordson Tractor Pages Forum

I have just rebuilt the engine of my NP Super Major. It runs beautifully after a good bedding in pulling a sub-soiling plough. However, it seems to run a little hot. On light work the needle sits at the end of the blue sector and with heavy work the needles sits halfway along the white sector. I wonder if the thermostat is opening at too high a temperature. I would be grateful for any advice. If it is the thermostat, which is the right one for the job and where can I get one?

Look at it like this. If you push an empty wheel barrow around the garden you won't break into a sweat, now fill it full of bricks and repeat pushing it around, bet you get a little warmer!

I would not worry as long as the gauge gets into and stays in the white, on light work the engine will hardly warm at all that is why they glaze up or the rings stick. It takes a fair bit of work to get the thermostat fully open.

In "the days past" we ran them with no thermostats in place without problems but they were in work every day. If you are worried, slip the thermostat out and check it. If you have fitted a new one of the latest design it is possible that the engine will not warm quickly as the proper 'stat was designed to shut off the bypass until the engine was reaching operating temperature. The new design just closes the path to the top hose.

The correct place for the needle to run is the centre of the white area, as yours does.

Hi Brian. The wheel barrow analogy explains all! My mind is now at rest. Many thanks, Adrian.

A word of caution of removing thermostat, apples to any engine, you need to restrict the flow to prevent the back of the engine overheating since coolant will take the easiest route and bypass most of the block with a stat removed. I test off highway machinery for a living including cooling testing, if an engine wont cool with a thermostat fitted then there is something wrong (assuming stat is working) Stats can be "jacked" open using a bit of brake bundy etc (usually around 10mm) but in winter your engine will suffer wear since it will not warm up quickly.
Not trying to say Brian is wrong since many a farm tractor has had a thermostat removed to aid cooling, the gauge may read lower because A) temp sensor is at front of engine and B) it can take an hour of continual use from cold even on a hot day for engine to reach working temp even with stat removed. The actual cooling capacity is governed mainly by the efficiency of the radiator, these get blocked externally and corroded internally which reduces the efficiency. Also waterpumps lose efficiency as the impellor corroded (some modern cars will overheat in a big way eg some rovers and it is all down to a failed waterpump).
Fordson thermostats should have a sleeve which is around the stat, this moves up as the stat opens to block off the bypass port I believe.
Regards
Ed

I feel that Brian's analogy hits the nail right on the head; but perhaps another one wouldn't be amiss as well. If you turn an open ended garden hose on water erupts out of the end for a certain distance. Place your finger over half the outlet and the water squirts a lot further out. Water pumps are designed to flow water to the far end of the block and cyl. head -- with the restriction of the stat. in place. Remove it, the stat, and marginal flow rate pumps will not do this [as mentioned the UK spec 6 cyl. Rover SD1 had a badly designed w/pump impeller].
In the early 70s when I worked at NIAE a couple of us played around [un-officially] with the the stat. on a Nuffield during a particularly hot '73 summer. By removing only the bellows and plate [or waxstat and plate] and refitting the stat. flange, the flow pressure was still good and the temp. was marginally lowered. Here in Oz many of us drill a 1/8th hole in the plate and this appears to help [in cars also].
Corrosion -- the bane of cooling systems. Here in W. Australia we have, according to the Encyclopedia Brittanica, the highest content of iron and calcium in our drinking water than any other country. Yet the answer is simple; use distilled water with an added inhibitor [or anti-freeze] even if you drain it for the winter months. Like good oil, it's very cheap insurance.
Pavel

OK, I know I am a dinosaur and this is slightly off topic but -

I started working with people on car engines in the mid 1950's and went into a large garage to serve my apprenticeship in 1959. At that time the majority of cars on the road did not have either water pump or thermostat. I got my first car with both in 1968. Ford did not start fitting either to their lower range cars until around 1961 with the introduction of the Ford Anglia. As overhead valve engines became the norm then so did water pumps and thermostats.

It is possibly because of this history that it was common to remove thermostats from vehicles that gave overheating problems as the thermostat was seen to be restricting the coolant flow. This was why they were removed, rightly or wrongly.

The thermostat that is sold as a replacement for the Major and Dexta is not the same design as the original. As has been stated in earlier posts, the original controlled the flow in the bypass circuit as well as the main flow so, fitting the later type MIGHT be on the same lines as removing the thermostat all together.

I tend to refit thermostats in vehicles that I find without them, but some have run for many years here in England with no ill effects, without them, as long as they have been working, not on light work.

Yes, I agree with you, Brian. If the cooling system of an engine/motor was originally equipped with a thermostat then it should have one installed -- even though the older thermo syphon systems worked well. My comments were in no way intended to lessen their importance, but rather to show that if push comes to shove there is a better way than just removing it entirely -- if only 'till a replacement can be fitted. The problem is that it is so easy to assume that the easily get-at-able parts, such as w/pump and thermostat, are at fault when in a lot of cases, especially in older engines, it is an accumulation of silt and corrosion that causes overheating.
As an aside, I too am of the 'dinosaur' brigade. I got my road licence when I was 16 in 1951 on an International W4. Even so, I'm still learning -- which is why I enjoy this site so much.
Pavel.

I have a question along those same lines. I just recently rebuilt my 1956 Major and the replacement thermostat from agriline was the newer style without the baffles. The tractor seems like it takes a long time to warm up, and I have yet to see the temp gauge go over 160* F, even during hard work (the tractor does not have shutters). Do you think an original style thermostat would work better, and if so where I could find one? Thanks.

That would not concern me at all. Around 160F is the normal range for those tractors. My original gauge has a white area around that temperature and that is where I try and run her, using the radiator shutters.

That's what I was hoping to hear, Brian. Thanks!

Hi Brian. A bit of a delayed post! I was chatting with a friend of mine recently who has around ten working Majors of differing models. He says that none of the Power and Supers he has with the same temperature gauge as mine (NP Super; replacement new gauge with yellow, blue and white sectors and with temperature range from 100c to 230c) goes as high as mine does. Just to remind you, I have recently done a total rebuild of the engine. She runs sweetly and in hard work (pulling a sub-soiling plough) the temperature reaches halfway through the white sector, which is three quarters along the scale from 100c to 230c, meaning she is operating at a temperature of approximately 185-190c. I notice in a separate post you mention that an earlier model Major should ideally run at 160c. Should a Super do the same or is it ok for it to run at the temperature mine is running at ie 185-190c?

Kind regards, Adrian.

My Major has the original gauge that was fitted to all Majors at the time and around 160 degrees is the marked area to run. I have not got more details to hand at the moment but I think that the later tractors ran a bit hotter. Will check and get back.

Thanks Brian!

Hi Brian and fellow members

I have now got my hands on an Operator's Handbook for a NP Super Major. It states: 'For optimum performance the cooling system should be maintained at a temperature of 160-190F (71-88C).'

It looks as if we are all operating within the optimum parameters, which means I have now got one of these on my face!

Best wishes

Adrian

This article gives an indepth understanding of how operating temperature affects the performance of a diesel engine, which was an education for me. The article states that 200F is regarded as an optimum temperature to ensure fast and complete combustion of the injected fuel as close as possible to the top of the stroke. An apparently paradoxical (but not when you read the explanation) result is lower exhaust gas temperatures. Another result is the reduction or elimination of 'smoke' caused by unburnt fuel.

As someone who knew a little about this subject, I now understand a little bit more! I think!

Best wishes

Adrian

http://www.monstermarketplace.com/diese ... thermostat