9" Fan Kits

[William2]

I need to purchase a fan kit for my S4 and was going to go for a complete 9" fan kit with adjustable thermostat. I assume that the temp. probe would be located in the upper radiator hose. Does this type of arrangement generally work reliably compared to the original Otter switch? What is the best way of sealing up the original hole in the rad where the switch would have been located as I do not have the old switch and rubber seal?

[AHM]

What is the best way of sealing up the original hole in the rad where the switch would have been located as I do not have the old switch and rubber seal?

The easiest way would be to buy a new otter switch! You wouldn't need to buy or fiddle around with the adjustable thermostat then either.

[TroonSprint]

This is something that I need too. I wonder if a thermo probe in the top hose works properly. Isn't it likely that the top hose is partially empty due to the impossibility of filling the system completely as the radiator is lower than the top of the thermostat housing? Cliveboy does a very nice fan kit, but it's expensive. He does single or double fans, but I can't see a double would be necessary.

Fortunately, my new radiator doesn't have a probe hole, so I can't help you with that problem.

Mike

[William2]

Mike, that also occurred to me, what if the top hose is empty or partially empty of coolant then I can't see that the probe would be reliable. Is the alternative option to locate the probe in the bottom radiator hose?

[nigelrbfurness]

Using the probe-in-hose system is perfectly reliable for twin-cams, despite the possibility of low water in the top hose, because when the engine is running water is being constantly pumped through the hose and the probes are very sensitive. The thermostat does not switch off immediately the thermal signal is removed, either, so if there is a brief drop in water level for some reason, then the fan will continue to operate for a few seconds to cover the interruption. I've used this arrangement many times over the years and found them to be consistently reliable - the early Kenlow systems used just such an arrangement. The modern replacement push-in Otter switches available from several sources seem to vary greatly in accuracy and cut in anywhere between 85 and 100C; I've also had two recent purchases arrive DOA. Also they equally need to be immersed in water to work, so the low water level argument applies to them too. If functionality is more important to you than originality, I'd go with a probe in the top hose. You can buy them cheaply enough plus there is no real problem setting the adjustment, fire the engine up, let it run until the temperature gauge is showing around 80C then adjust the thermostat so the fan cuts in. Job done. And it is very easy to observe its behaviour.

One tip to make the job easier is to buy a spare thermostat housing gasket so you can remove the top hose with the thermostat cover as one unit - this saves you the job of having to manipulate the hose off both the rad and the thermostat housing.

Once again if originality is not your thing, a pair of Suzuki GSR600 fans is much more efficient, quite likely a lower electrical load than one single 9" fan and looks so much, er, cooler.

[69S4]

I'm sure I posted a reply here yesterday but it looks like it got lost en route as nothing is showing

Anyway, the point I was trying to make is that a previous owner did a Kenlowe top hose thermostat conversion on my S4 many years ago and whilst it works ok when I calibrate it in hot water to set the on point it's unreliable (= inconsistant) when the car is running. I'm fairly sure that's down to the top hose not being filled when the engine is at idle in traffic although there may be other reasons I suppose. My cheap fix for it has been a manual bypass switch.

[terryp]

I think you may be better of with the Revotec in line switch. You basically cut out a section of the top hose and it's inserted inbetween the parts. I installed one on my old +2. You can vary the temperature to switch on the fan. I never had a problem with no coolant in the top hose but I did have the recuperating system working fully.

Terry

[TroonSprint]

Are the Suzuki fans mentioned by Nigel pullers or pushers? That is, do they mount in front or behind the rad?

Mike

[elanman999]

EErr,
Why is the top hose not full of water? If your recuperator bottle system works correctly then it will be.
I use 9" fans from Car builders solutions now controlled by the ECU but before that I used a Revotech probe in the top hose.
Edit , in the past I have used a Kenlowe probe in the top hose but found the sealing of the probe a bit of a problem
Cheers
John

[nigelrbfurness]

To answer Mike's question, the pair of Suzuki fans I have will run in either direction depending on how you wire them up, so you wire them to push and fit them in front of the radiator. So they will pull or push as you wish, really. There are undoubtedly other motorbike fans that will do the job, a browse through ebay usually pulls up a few.

Not having water in the top hose sounds a bit odd to cause the problem described. If you take the radiator cap off and start the engine, does the water disappear? Doesn't on any of my cars, even when the engine is hot. And you can usually see it pumping round, so perhaps we are talking about a slipping fan belt here? I'll admit that if you rev it, the water level does appear to drop in the top tank momentarily. I can see that there might be low water at the thermostat housing as it is higher than the radiator, but I wouldn't have thought that it would be immediately beyond the top hose connection to the radiator, which is where you'd put your probe. If you were really worried by that, the last one I bought (a few weeks ago) came with a thin enough pipe to enable you to wiggle the probe actually into the radiator top tank (although I didn't, though I might have if this thread had emerged then), so it would be slightly lower than the otter switch and rest on the top of the matrix. The same problem, if that's what it is, will therefore afflict any solution that involves measuring the temperature in the top hose, will it not? Anyway, I stick by my previous assertion, I've used various makes over the years and not seen any strange behaviour at all, nor ever had an engine overheat with one fitted. At that point I rest my case.