Cooling System Issues

[Guest Dan_Norfolk]

Hi all, I'm new to the forum and new to the kit car world; I bought a Robin Hood running a 2 litre pinto engine back in August and drove it around for a couple of months before garaging it for the winter. Now that spring is around the corner it's time to get the car ready for the summer so that I can make full use of it. One of the issues that I need to sort out is the running temperature as it runs a little hot.

 

From the day I collected the car it has been running a bit hot (temp gauge needle sat at the very top of normal and occasionally touched inside the red). I got the car home without it overheating (100 mile journey which in hindsight I should have done with a trailer). I took the car out for a couple of smaller runs when I got it back and the problem persisted so I took a look under the hood. The bracket which mounts the alternator to the engine had snapped at one point which meant that the belt which comes off the engine to drive the alternator and water pump was running a touch slack. This was obviously causing some inefficiency in the water pump therefore causing the engine to run hotter than it otherwise would. I got the bracket welded back up and got it all back together and it has helped the issue but the car still runs a fair bit hotter than I would like.

 

So, given that the water pump now has a good bit of tension and the system seems to be running to the maximum of its cooling ability I am looking at what measures I can take to improve the cooling capacity of it. It currently has one large radiator (which runs at an angle so that it fits into the chassis), this in turn is fed by two fans, one which is attached to the face of the radiator and the second which sits directly behind the grill to suck more air into the engine bay. At the moment the radiator just has standard anti-freeze mixed with water. The fan behind the grill kicks in after 5 minutes or so but there is an override switch so that it can be switched on from cold but either way it makes no difference, the temperature is always sitting towards the top end of the normal zone.

 

I'm not sure if the current radiator is the most efficient option. It is obviously larger than the typical option however as it sits at an angle it wont be as efficient as one which is sitting vertically. I guess I need to know whether it is actually better than a smaller one running vertically. If the radiator that I have is the best option then I suppose some options I have are uprating the fans and looking into other coolants I can use. Any thoughts on the above would be greatly appreciated. Thanks

[theduck]

Does your existing setup having an expansion tank?

 

 

[Peter Bell]

Hello Dan, first of all is it actually running hot or is just the gauge telling you it is? a missmatched sender/gauge combination is not unusual as there are quite a few different senders, so try to find out the actual temperature. It sounds a bit of an odd setup with 2 fans, personally I would get rid of the fan in the grill as it will act as a restriction and just have the one fitted attached to the rad. some form of cowling around the rad to stop air passing around the radiator will help. Normally getting air into the rad is not a problem, getting it out of the engine bay so there is a good flow is a different matter, most cars have additional vents/louvres in the bonnet to improve this. If you do a search on this site you will find quite a lot about this subject. Whereabouts are you, there may be someone near to help or at least drink your tea.

[speedtripledan]

My tuned pinto ran that rad, 1 decent fan should be enough I also used an 82deg stat it only ran hot when thrashing it on a hot day Sounds like the gauge is wrong to me. Perhaps buy a 52mm gauge and hose adaptor and see if that concurs with your existing gauge

[Guest Alan_builder]

Hi Dan,

 

This is a well documented problem on this forum.

Unfortunately everyone including myself has a different opinion. Your problem will be to find out what advice to take.

Lots of owners report overheating, My 2B/04 (sloping radiator) has boiled over three times, once when the expansion tank split, once when the radiator split and the last time was when the fan ran the battery down! This last occurrence was in France queuing for the telepayage some 6 miles in 38 dec C a long time on tick over (no airflow) and no battery charging! My electric fan never cut in unless I was below 20mph or in 1st gear all the time.

 

So my point is if your water system is sound and installed as Ford & Robin Hood intended, it is fine, however many will claim you need extra vents, may be if you have a 200BHP Pinto but first look at what you have, the heater / carb bypass pipe are common problem areas.

 

Peter Bell's reply starts off well, buy a cheap Laser temperature probe £10 on flebay so you can check. (You can always check the laser temp reading against a boiling kettle of water) but these things claim 2 deg accuracy.

Is the thermostat working? What temperature one is fitted?

 

So tell us about the car, power out, chassis type as these have big effects.

My best words of wisdom, don't try fixing non existent design flaws, make sure what you have works correctly first. Ok just remove the fan behind the radiator but only if you have a proper push fan fitted in front.

[Al Milton]

As Peter says, do a search and you're sure to find the answer to your problem.

 

I had an issue with overheating on my Zetec, so as part of the fix I fitted the largest sized fan that would fit on my rad.

Not one of the cheapo's from e-bay, but a Pacet, shifting around 1300cfm.

This provides plenty of cooling and the heat is removed from the engine bay as you can feel the draught at the rear of the car.

 

Each set up will be slightly different, but I used a process of elimination to find the cause and then put the rectification in place

[Snapperpaul]

Biggest difference for me was fitting the 82 degree thermostat, only costs a few quid

Pressurised systems only raise the boiling temperature they don't make it run cooler

Ducting the air from the nose through the radiator helps a lot, simply filling the gaps at the side of the radiator will force all the air through the rad.

Both these mods are cheap and simple

 

The thicker Coolman radiator is the next step but more costly

I run a twin 42 core rad and 82 degree thermostat for a high performance engine and it runs mid to high 80's

[Guest Dan_Norfolk]

Thanks for all of the replies, much appreciated. It's a 2B+ registered in 2005 in case this helps (I'm not too sure how much the models differ at the moment)

 

Duck, the car didn't come with an expansion tank. I was looking into incorporating one into the system but as yet I've not found a small enough tank and worked out how it would fit in. I'm hoping that I can find some inspiration on this by looking through other exisiting threads.

 

Peter, it has overheated a couple of times, however I think the second time was just an airlock coming out as a result of the first time. There is a water pipe that runs over the top of the engine and then feeds through the manifold so that causes an issue when the system gets topped up. Given that it has overheated it does seem that the temperature gauge is giving a true reading. I've been told that I might as well take the thermostat out since it's likely that I will only be using the car in the hot weather. Have any of you guys done this too? Will happily look into other thermostats too as suggested and see what I have fitted at the same time. I will check the sender unit and see if it is giving an accurate reading also.

 

I agree that the first fan behind the grill isn't really doing very much and could in fact be a hindrence. I suppose the only time it has any noticeable and useful effect is when the car is stationary. I think I will remove it for a bit and see if it makes a difference. At the same time I will see what kind of clearance there is around the radiator to see if I can restrict any airflow that is bypassing it. I will also check the rating of the main fan to see if it is powerful enough.

 

For the number and location of vents in the hood, there are several on the bonnet but I would need to look and see how this compares to other 2Bs to see if they are providing enough escape area. I will look at the other areas first. I don't have a 200BHP engine but I will check the bypass pipes. Forgive my ignorance but in what way are these common problem areas? Do they get blocked or restrict flow by other issues?

 

It looks like I have a lot of investigation to do to determine the most appropriate action to take. I will have a good look over the car in the next few days and report back with my findings! Thanks again for all the advice.

[Longboarder]

Previous posters have given all the usual advice and the solution is probably in there somewhere. You have not described the problem clearly enough to help narrow down the likely cause so this thread is building a reference work of possible causes of overheating in Hoods but not specifically tailored to your problem.

You have said it overheats shown by the needle hovering at the edge of the normal/hot zone of the gauge. Does it boil over and blow out steam and water? When does it overheat? At 20 around town, while idling on the drive or at 80 on the motorway? Does it have a heat sink problem where it boils over a minute after stopping in a motorway services.

Next thing you need to know is how hot does the water get? You need another way of measuring its temperature. Does that confirm it's running over say 95C?

Having two fans in series in front of the rad is odd and makes me think the previous owner had or thought he had overheating problems and you have inherited them?

I don't think the front fan is likely to be a benefit and is almost certainly reducing airflow so I would remove it.

The thermostat adjusting flow/route of the cooling water is a time honoured and effective way of maintaining the running temperature of an engine. It relies on there being potentially more cooling capacity available in the system than would ever be needed. Removing the stat is a desperate, potentially harmful and usually ineffective action.

A radiator slightly angled to the airflow is supposed to be more efficient than one set at 90 deg to it.

A fan is more effective if it has a cowl, i.e. it's in a tube close coupled to the radiator surface and also more efficient if sucking from behind the rad than blowing from in front. (If it's in front of the rad check it is actually blowing and not sucking.)

It would also be helpful if you could rough out a drawing of your system pipework, components and flows including a heater if you have one.

With that information assembled you can make a much better job of working out if/why your engine gets too hot.

 

Nigel

[Snapperpaul]

The 16mm bypass hose in your instalation is now the highest point in the system and will cause air locks

You should fought round the front or back equal or lower than the gasket level.

I fitted a plastic bleed T and route round the front clipping it away from the cam belt, you can top up throught the bleed T eliminating air locks

 

Caterham, Westfield, kit car, Bleed Tee / Coolant valve

eBay item number 300836511252

 

Edited January 2, 2013 by Snapperpaul

[Guest Alan_builder]

Hi Dan,

 

Lots of people are sold 2B's and they are not, pictures from the front with close up of suspension, put some pictures from under the hood to.

 

The layout of the bypass hose can cause problems as you say air locks but others also like being a better route to return the water to the pump than through the radiator for cooling. Do you have a heater? My front radiator fan was donated by a Peugeot 205 and I have not blocked off round the radiator. Its a 2L EFi with lagged 4:1 exhaust pipes. Driving it runs middle of the normal and one can just see the thermostat open and close as the temperature rises and falls slightyl, thrashed it climes when you slow down and then returns to normal. On tickover the fan takes more power than the alternator provides so eventually it overheats due to the fan slowing down as the battery looses charge. See my web pages for the cooling system I installed prior to EFi upgrade. (yes I have seen poor layouts of hoses from those who I thought new better).

 

Why fit an 82 degree stat when the Ford one was 87? (see the Haynes Manual normal operating 88 C). The Pinto runs hot, if you read the blurb it was designed to run hot to give it the power and fuel economy. If you lower the operating temperature you will not have the correct engine oil temperature or clearance tolerances?

 

As Nigel says more input.

[Snapperpaul]

The Pinto runs better with temp lower, more power

Early opening stat gets the water flowing earlier so it is fully open at the required temp, the 88 degree one always struggles in a 7, any power upgrades ands its not adequate

The engines in 7 type cars run hotter because there is much less airflow through the bay

 

If you want supportive evidence as to ideal running temp for a pinto ask on Turbosports forum

[speedtripledan]

agree with snapper re stat anything other than the 82deg and it was running to hot, henry ford also put these engines in large well ventilated engine bays with massive rads the 7 environment is not the same nice stainless panals reflecting heat back etc

 

Once my pinto was tuned it generated a huge amount more heat and the above solution worked well, use all the above info in the posts and draw your own conclusions

[richardm6994]

A radiator slightly angled to the airflow is supposed to be more efficient than one set at 90 deg to it.

 

Nigel

 

Not meaning to hi jack this thread, but just a quick question picking up on Nigel's comment? Please don't take this the wrong way because I'm not argueing what you have said Nigel, but I'd like to know more about why the radiator at an angle is more efficient than if it was at 90degrees?

 

I'm looking at the new position of my rad (it's moving further into the nosecone), and it looks like it's going to end up at a slight angle (bottom of the rad further forward than the top). I've assumed it would be better at 90degrees and as such I've been thinking of numerous ways to avoid the angled mount, but if you're saying its better at a slight angle then it solves my problem without doing anything!

[Guest snotfart]

I suspect improved performance might be due to the additional turbulence through the rad core,only guessing though,I had the same problem accomodating a large enough rad vertically and gave up and fitted it on the slant(about 30 degrees )it works fine.Dave.