Hello All,
I'm new to this forum so please bear with me. I have recently purchased a locost and the overheating trouble started when driving it home that same day! Basically I had a long journey back and had to stop 3 times on route to allow the engine to cool down as the coolant was boiling over and when I had finally got home the engine had reached 130deg.
The engine being a ford kent 1.6 crossflow.
Since this happened i have been trying different things to try and rectify this overheating issue such as removing and checking the thermostat to find it was not there! Removed and checked the water pump-seems ok. Removed hoses and flushed system through with water- all seems ok. Fitted a better fan onto the back of the radiator so it's dawing the air through rad and blowing out over engine. Changed rad cap to higher pressure rated one as old one let by.
Other points to mention- expansion tank is brass type with outlet near the top but piped down inside to the bottom- this I have removed and soldered a straight outlet to the bottom of the tank and blocked of the old one. This outlet tees into the rad top hose to thermostat housing.
There is also a pipe from the water pump going into the bottom of the carb body/inlet manifold.
The top hose is on a very similar line to the outlet on the expansion tank but I cant get this up any higher than it already is under the bulkhead.
The fan is wired direct via a switch so I have this running all the time the car is.
Everytime I go out after a few miles the temperature climbs steadily past 80 onto 100 + and then I have to turn back as the coolant starts to boil.
Evidently the rad is from a 1.3litre cortina as I guess a larger one would not fit into the nose cone but tbh I dont think this is the cause.
Anyone have any ideas/knowledge that can help me sort this please?

Have you tried back flushing the radiator with a hose as that may have become blocked with sediment? To make sure you don't get and air lock jack the front of the car high up in the air or fill it on a steep slope and use hot water out a kettle, once you have replaced the thermostat. Your hose configuration is normal for not running a heater. Also use a 50/50 mix of antifreeze rather than plain water.

Failing that I'd do a compression check on the engine to see if the head gasket is sealing

[Edited on 6/9/13 by Mr Whippy]

Ok thanks Mr Whippy i will give it a try once my thermostat has arrived!

I have flushed the rad from the top hose but not putting the hose into the bottom outlet to see if it comes out the top. How does this back washing the rad out differ from the other way?

cleans out any crud/sludge thats built up in it.

I had a crossflow that ran very hot too. I'd recommend fitting a polo rad (have a search on the forum lots of info), and making sure your using good coolant. I've been told 'Water Wetter' is a useful additive, but never used it myself.

make sure to use a thermostat too - it may be the water is flowing to freely and not scavenging enough heat from the engine (sure someone on here told me that!).

Good luck, but the only thing that cured our over heating was fitting a Zetec

I had the same problem and turned out to be the return pipe to the header tank was blocked with sediment/something else and not allowing the coolant to be pumped round the system, try taking the hose that feeds the header tank off and fill up the coolant, turn the engine over and see if the coolant is being pumped round the system and out of the pipe (don't burn yourself). If no coolant comes out then you either have not bled the system properly or there is a blockage, if it is pumping round the something else is causing it.

Matt

A cortina rad is going to be pretty old, it may be worth biting the bullet and installing a £30 polo rad instead.

Back flushing is pushing water the opposite way through the rad, it is pumped by the car into the top and extracted from the bottom, by reversing you remove more crud as it silts up differently depending on water flow direction.

If the radiator feels heavy then I expect it is blocked, a kill or cure approach I have used in the past is to remove the radiator, fill with old battery acid and slosh about for 10 minutes then drain and run a hose through to flush out, you get lots of rubbish removed like this.

Regards Mark

Are you sure the ignition timing is right ? as this could be adding to your problem,

also, were are you based, as someone local may be able to help

steve

I had a similar problem when I first began using my x-flow - eventually I found that the problem was due to an airlock under the thermostat. I know you don't have a thermostat, but in investigating this problem I learnt a lot about this engine's cooling system when fitted to a Locost!

First of all, fit a thermostat! But before you do, drill a small hole through its base plate to let some air through. Something around 2.5mm - 3mm dia is fine, well away from the important bits.

When you fill up with coolant, keep squeezing the big hose connected to the water pump - this pushes the water around and (hopefully) pushes air along with it. The hole in the thermostat plate helps with this process as it lets air through during bleeding; it also lets air through while the engine's running. I have this sort of thermostat housing, and you'll need something similar if you fit a Polo radiator as that doesn't have a filler cap. It has the bonus that you can look down on the thermostat while you're clearing the airlocks and can see when the bubbles stop. I should point out that it was far cheaper when I bought it, and some shopping around may be in order!

There's a very good description about overflow tanks and how they work here.. He's talking about a Pinto engine, but the x-flow is identical in this respect.

HTH,
David

[Edited on 6/9/13 by David Jenkins]

Thanks guy's, all points much appreciated. i'm based near Sudbury in Suffolk.
i did wonder whether having no stat at all would hamper the flow of the coolant, especially around the block.

I had no end of coolant problems with my pinto, in the end i decided to bite the bullet and re did the cooling system completely i brought 2 bottles of coolant flush and flushed all the poo out the system before stripping down and replacing the head gasket, water pump fitting a low degree opening stat, replacing all the hoses with silicone from ebay and fitting a new Rover 25 header tank with a new polo rad and a 86degree fan switch for the rad fan.

the other thing i did was install the rad sitting verticle as my original install had it stilling slightly back and this was hampering the coolant, and causing air locks, now i rarely get over 88 degrees even on the hottest of days and the fan keeps the engine cool in traffic nicely.

the other thing to check is that the mesh in the nose cone isnt causing the air to be restricted coming in the front end, i remember reading about a guy on here who had fine mesh in his nose cone and it was acting like an air damn causing overheating.

Cowling in the front side of the radiator up to the nose cone is also a good idea to make sure that all the air goes through the radiator. Air will find the path of least resistance and without the cowling a lot will bleed around the edges.

I run a xflow, and do not have a header tank (now), just the filler that David J has,
before I went down the route of the thermostat /filler I had no end of problems, so ditched the header tank
and now it runs fine

steve

Thanks again for all your replies. I will let you know how I get on!

When replacing the core plugs as a matter of course when rebuilding a crossflow in a mark 2 escort years ago I found the remains of a couple of even older core plugs sitting in the water jacket. Whoever had done the job in the past must have just knocked the old ones in and forgotten about them. It didnt take too long to fish them out with the engine on a bench and it did run a bit cooler afterwards.

Essex Kit car club

Perhaps we can help, your not far away ( I have friends in Sudbury) and Chelmsford where we meet is an easy drive

Run the engine with no stat,with no rad cap on you will see the air bubbles comeing out ov the system keep squeezing the hoses.also put heater on so you no system in completely full and no air locks . Refit cap feeling the veins in rad to see if is all getting hot .if this fails I'd advise a local garage were they will do a chemical head gasket test.

What pressure caps do you have fitted?

With your brass tank type, you need a plain cap on the rad, and the overflow blanked, and the pressure cap on the brass tank.

If you have the pressure cap on the rad, and the radiator top tank is below thermostat level, the water level will settle way too low, and cause the overheating.