Urgent advice needed - radiator plumbing

[gouldsborough7]

Hi Guys
Sorry to hog the Forum page again. Just had overheating problems with my Hunter, and need a quick fix to keep the car going.

I first noticed the problem when the temperature gauge started climbing towards 100 degrees. It usually reads around 90 degrees quite reliably. First thoughts were duff electric fan, and on experiment I found the fan itself was operational, but something was wrong with the electrical circuitry and it wasn't being switched on when the temperature got too high.

As a temporary (maybe permanent) repair, I have hard-wired the fan to a large illuminated switch I installed down by the ignition key area. So now I operate it, not some electrical gubbins attached to the engine. I also double-checked that my mod makes the fan blow through the radiator. Despite leaving the fan ON on a couple of days with air temperatures in the upper twenties, the temp gauge still reaches 100+. It doesn't actually boil, but not wanting to push my luck, and each time I stopped for 5 minutes to allow the engine to cool off! Switching on the heater helps, but my feet don't like this!

At a local kit-car meeting (SG7s - great guys & gals with allsorts of kits) in Baldock today, I discussed the problem with a couple of guys. Straight away one culprit suggested was the engine thermostat. I've have just janked it out of the housing and plan to replace it tomorrow. Other thoughts were that the raditor needs flushing out, and/or the fan is too small (it measures 300mm in diameter).

Another surprising idea suggested was that the top & bottom hoses to & from the radiator are coupled upside-down, i.e. the hose from the thermostat housing on the engine (adjacent to the alternator) is coupled to the radiator at the BOTTOM, and the hose from the water pump is coupled to the TOP of the rad, with a top-up cap halfway along the hose. In my experience, these connections are usually the other way around.

Does this upside-down arrangement matter? It should be born in the mind that the car was factory-built 12 years ago with all-new parts, and has done only 10,500mls. Also, I have driven it for 2,000mls without any overheating problems, until this recent heatwave.

Your advice/suggestions would be much appreciated.

Cheers
Mike

[CABRIOBOB]

Re: Urgent advice needed - radiator plumbing

If its a Pinto engine you may have a stuck open thermostat and have been very lucky and is now getting hot due to the hot weather, but the top radiator hose goes to the thermostat on the cylinder head and the bottom hose on the rad goes to the water pump.

[dcunn]

Re: Urgent advice needed - radiator plumbing

If the hose with the top up cap is not horizontal, and is below the top of the rad. header tank it is possible you have air in the system and not totally coolant ???
Just a thought

[danny_nelson]

Re: Urgent advice needed - radiator plumbing

Hi Mike, This was the way that Mark Matthews plumbed the 8valve twin cam engine. There has been a lot of debate on this over the years.

[cabrioman]

Re: Urgent advice needed - radiator plumbing

Mike

Whilst I have never been very convinced about running the cooling system with the hoses reversed, (after all Ford tend to check these things out)I didn't have a problem with my 8v plumbed this way. I think given its been running ok before, I would go back to basics and start by checking the thermostat open temp or just remove it to check if it solves the problem. After that you can start to scratch your head harder if the problem is still there.

cheers

John

[gouldsborough7]

Re: Urgent advice needed - radiator plumbing

Thanks Guys
The engine is a 1998 2 litre 16v DOHC Granada injection. Its design is slightly uncertain as there is no engine number to check against. Some kit-car mates are a bit puzzled by it all, as the 4 sparking plugs are sort of horizontal on the offside, and not vertical deep in the middle of the valve cover.

I think for the moment I will leave the plumbing as it is, as it has obviously worked OK for 12 years and 10,500 miles. I am in the process of renewing the thermostat, and will also thoroughly flush out the radiator with Holts Speed-Flush. This is the type of cleaning fluid where first you drain out the antifreeze coolant, and refill with just water + the fluid. Strangely, there is then a choice of running the engine at a standstill for 10 minutes, or on a 20-30 mile journey. I would think the latter is more thorough, and plan to do that. Finally, after another hosing out, antifreeze mixture replaces the water/cleaning fluid.

The hot weather has been exceptional, but maybe if all else fails I should uprate the electric fan. The current one is 12 inches in diameter, with straight blades. I could go for either a bigger one, possibly squeezing in a 14 inch model,or the same size with more efficient curved blades. Big problem with the Hunter is that the 'nose-cone' is a big one-piece job, and looks to be a nightmare dismantling job to do anything to the fan.

I'll provide feedback to the Forum in due course, when I have hopefully cured the problem.

Cheers
Mike

[gouldsborough7]

Re: Urgent advice needed - radiator plumbing

Follow-up:
I've flushed out the cooling system quite thoroughly, including the small tank below the radiator. Not sure what its main function is apart from increasing the total capacity by a few pints, as it does not have any form of cooling fins or vent slots. Any ideas?

Checked that the electric fan (mounted in front of the rad) definitely blows back thru the rad towards the engine, checked by placing a sheet of paper in front of the grill to which it becomes stuck while the fan is running.

My village garage proprietor (who is into fast cars, Santa Pod and all that!) recommended that I use a coolant additive (Red Line 'Water Wetter'). He gave me some to try, by I suspect it was not quite enough. Have ordered some more from Demon Tweeks.

The result at present is that with the fan running constantly, the engine does not overheat with an air temp of 28 degrees. The temp gauge shows a higher reading than previously when the weather was cooler, but not so worrying. I'll try more Water Wetter in the rad, and might replace the supplementary water tank beneath the rad with an oil cooler type of rad (assuming one is available).

I am hoping that I wont have to remove the existing radiator to either replace it or get it professionally flushed out. Question: how the devil does one remove it? Looks like half of the front of the car has to be dismantled. Your advice would be welcome.

Cheers for now
Mike

[CABRIOBOB]

Re: Urgent advice needed - radiator plumbing

Mike.
You are correct, It depends on how much room you have in front of your engine and if the radiator side fixings are in front or behind the uprights. If radiator fixings are on the engine side of the up right supports the radiator will come out (just) without removing the front nose, but you will have to remove the bonnet and water pump pulley and viscous fan if fitted. If the radiator side fixings are behind the uprights then you will need to remove the head light bar and the front nose to allow you to lift the radiator out.

[gouldsborough7]

Re: Urgent advice needed - radiator plumbing

Hi Bob
Just had another squint at the likely problems facing me if I ventured down the rad/fan removal route. The front nose looks as if it is held by at least 3 nuts/bolts on each side of the horizontal 'apron' under the headlight bar.

Also,inside the engine area there are 2 large Pozidrive-type screws going into the vertical part of the nose on both sides. So that's 10 screws/bolts minimum that I can see. There's bound to be some others! Also, the headlight bar will be in the way, so that means uncoupling the wiring before unscrewing the bar on both sides. What a design! What a pain in the proverbial! Why couldn't Marlin have made the grill removable with a few self-tappers? That may well have helped a great deal.

When I flushed out the system, the rad appeared to be clear, because when I poked my garden hose on full bore in the top-hose connection, the water poured out of the bottom hole with no apparent restriction.

As a likely solution for hot-weather running, I am tempted to buy a jumbo electric fan from Car Builder Solutions, say a 14 inch diameter, and mount it between the rad and the engine. There is a fair amount of room there. (The existing fan is on the front of the rad) I could then wire up the 14 inch on another switch, and have that as a back-up. All a bit Heath Robinbson, but so what! Better than boiling over!

Cheers for now
Mike

[gouldsborough7]

Re: Urgent advice needed - radiator plumbing

Hi Guys
Thought one or two of you might like to know my progress for future reference. Apart from lots of flushing-out of the rad and pipes, I have fitted a supplementary radiator.

I identified the existing rad as fitted by the factory as being of Ford Escort size, and realised that the correct size for the 2 litre Granada engine would not have fitted in the restricted space of my Hunter. The factory had also fitted a small aluminium tank beneath the rad, which is in the heater plumbing circuit. Apart from increasing the overall capacity of the cooling system, having no fins or slots it does nothing to get rid of any heat!

So, as an experiment in the same circuit as the aluminium tank I have fitted a Ford Focus heater matrix. This is well finned and should assist in removing some heat from the cooling system. I have mounted it between the rad and the engine on a home-made bracket.

Into the coolant, I have also added some Redline Water Wetter, which on advice from my local garage (with dead keen young proprietor, sprints cars at Santa Pod etc) will help to get the the coolant to circulate the system more efficiently. A bit like Warfarin prescribed to people with bad blood circulation!

So far I have only made a few short trips to ensure that airlocks are removed from the system. All is well at present! Needs another heatwave to really test it all out. The final tweak might be a bigger electric cooling fan, say 14 inch diameter. Think I have worked out a way of removing the grill to swap over new for old fan, without dismanting the whole of the front of the car.

Cheers for now
Mike