Radiator removal

[Exowner]

Hi All, what a summer! I've had plenty of wonderful days to familiarise myself with AK1500. All's going well, but it does seem to be running hotter than I'd expect, even when the weather's cooler. It runs it's fan constantly once it gets to its normal temperature (between 80 and 95, sometimes a bit higher) I want to take out the radiator and to check the fan sender is opening and closing the circuit correctly and that the thermostat is opening and closing correctly and if it's the right temp range.
   
   So, 5 questions
   1/ can the radiator be removed through the bonnet aperture once the bonnet, wheel arches and various ancillaries have been removed?
   2/ What is the correct rad fan sender  (cut in and out temps, part number?)
   3/ What is the correct Thermostat (cut in and out temps, part number?)
   4/ Any recommendations regarding flushing/descaling the radiator core?
   5/ Does anyone know if a fan that is being driven constantly effects the cooling capabilities of the system, one way of another? I tried working it out, but it clouded the void between my ears.
   My engine is a standard EFi
   
   I hope some of you out there can help

[wenzeh]

I found that the best way on AK 1005 was to remove / install the radiator from bottom - you can remove the two lower brackets an then drop it down.   Even with a big engine my fan starts only to operate when outside temperate is very high and car is not moving a lot (stop and go).

[Flyinghorse]

Glen,
   When I had similar issues on a CRS I found one of the keys was to work out if  its really running hot or just the sensors think its hot. The sensor layout can be misleading,at least on my car-I have none on the radiator all on the heads/inlet manifold(the fan on off  thermo switch is near the thermostat housing,and the temp sensor is on the nearside in a well on the inlet manifold)
   I checked my timing was not retarded,and  cross checked the temperature gauge reading with an ( IR)infrared gun. I also took the temperature sensor /gauge out and checked it,and bled the air from round about it.I also tried no thermostat for a while.
   Other basics to check are fan rotation,and if the ducting/front grille are all set up to get maximum air through radiator.
   
   Re points 2/3--is there any reason to suspect yours are not original,but possibly non functional?
   
   I use one of these thermostats:
   http://www.summitracing.com/search/Brand/Milodon/Product-Line/Milodon-High-Flow-Thermostats/
   
   Re point 4 --I have used fernox central heating cleaning fluid recently in one of my other cars to flush /descale the system but you really need to get the rad  out and reverse flush it several times. I have also sat radiators in marine clean (frosts)overnight. If the rad is blocked thaen the heater matrix may also be needing flushing--does the heater work well?
   
   I dont think a new radiator is that expensive and may be the best way to proceed if a bunch of rubbish comes out the existing one.
   
   Re point 5 given the radiator and the air flow from driving  act as a heat exchanger having the fan on all the time will just increase the heat exchange capacity to a point/drain the battery.This assumes the fan rotates the right way.The other thing pushing the water arround is the water pump. The most important factor will be the rate at which the water passes through the radiator and the assisted heat exchange capacity of the radiator. Taking some IR readings on the bottom hose may indicate how well the radiator is doing.
   
   Lastly --you can get air locks. I rigged up a hose to the top of my radiator to ensure I could bleed all the air out.
   
   I even got to the point that I thought my water pump may be running the wrong rotation as the drive belts orientation was changed on my car,and then I looked at the pulley size as that determines the water pump rpm and hence driven flowrate.
   
   Graham

[Exowner]

Wenzeh, many thanks for the advice. It came out through the bottom with no trouble at all. Once again, many thanks for replying.
   Graham, also many thanks to you for taking the time to pen a detailed, informative reply. I shall use your guidance to work my way through this 'running hot' issue. I'll post my findings in due course. Many thanks for sharing valuable knowledge. Glenn

[Superarnie Mk2]

Hi Glenn, I wonder if I could trouble you to take a few images which will show how the radiator is installed/mounted (top and bottom).I have an AC Superblower which was built by AC Cars in 2001 but was never completed as they went bump. I have been completing the build of the car for the last 12 years or so. I am at the point of purchasing a radiator and giving thought to how it is installed. Any images you or other AC Mk4, CRS or Superblower owners would be very much appreciated. I'd also be interested how the oil cooler and shrouging is fitted if you can help. I suspect the oil cooler shroud and radiator mounting are interlinked some how??
   Kind regards
   Gary

[Exowner]

This is what I found. The thermostat had the markings- A160 and 4180, nothing else. I assumed (dangerous) that the 160 may be the opening temp in Fahrenheit (=71cent). I placed it in some near boiling water and nothing happened. I placed it in a pan with a thermometer and turned up the gas, as the temp reached 99 deg C it opened a fraction (no more than 1mm) and I noticed that there were signs of leakage of a waxy substance! I considered it to be U/S and sourced a new'un with an opening around 70-75 deg C.
   The radiator seemed to be in reasonable condition inside. No worrying amounts of muck or restriction in flow were evident. Upon inspection, the gills of the core were quite considerably blocked, especially the lower third, with insect and road debris. Also quite a lot, maybe 5-10%, of the gills were 'bruised'. First I spent an age straightening out the gills, after which I drove out almost all of the debris by repeated water hose and compressed air from both sides. This took an age as the gills are perforated and are almost designed to trap anything that gets past the outermost edge. It is not possible to poke anything other that a slim pointy thing through them (which does nothing expect further compact any debris!!), anything else catches on the gills and does more harm than good. My patience and persistence were rewarded and I was very happy that the radiator was almost 'as new' once it had a light coat of mat rad paint.
   Next, the fan switch which is located in the top hose connection of the radiator. Its 'on' temp was 86 degC and its 'off' temp was 77 degC!! No wonder the fan was running all the time. I didn't even bother testing it. I replaced it with one that goes 'on' at 95degC and 'off' at 88degC.
   With it all reassembled, it was time for a test run (I checked there was no air trapped in the top of the rad by cracking the bleeder at the top/front of the rad). Fortunately the weather was pretty hot when I test drove it, and low and behold it performed beautifully. It held a temp very slightly beyond midway between 70 and 100 on the gauge. It held this even when I kept it in 4th for an extended time. At no time did the fan come on. In the driveway I let it tick over until, at about 95 on the gauge, the fan came on. It remained on for maybe 4-5 minutes during which the temperature steadily dropped and the fan stopped, as expected, at about 85 on the gauge.  The test run was completed without the intake deflector or the number plate and bumper assy. Whether or not this will make any difference, who knows? I suspect not, now that the cooling system appears to working as it should.
   So there we are,  all done and I'm very pleased with the outcome.
   Many thanks to all who contributed. Glenn