hi All,

My fan clutch seemed poor last year, it would not tighten up significantly when hot. I got a spare from a junker. I installed it this weekend, but this one seems maybe even more loose than my original...

OK so they have a heat sensative coil at the front, which turns with temperature increase and turns a center shaft which *apparently* should tighten the clutch. Both the ones I have have intact coils. I put a torch to one coil, in turned about half a turn as expected. The clutch did not tighten up.

Both clutches are very *damped* when I turn them by hand, they are in no means loose, it's just that they don;t tighten up any more. I took off one coil, and verified that the total turn amount of the shaft seems to be about 1/2 turn, hence it is turning to max capacity, just not tighteneing up the clutch. So problem is inside.

Q: Are these repairable? Is there any way to open? The screws all stripped, so they would need drilling.

Anyone have any advice, other than electr fan, or buy a new unit...

Let me know.

Greg Mustang
Montreal
Canada

As vvpete mentions the coil spring in front of the clutch is a bimetal that change form with heat. With heat it is opening a valve inside that let the oil flow in the friction disks chamber. This valve is simply a flat metal piece approx. 1/2 in. x 2 1/2 in. that is welded in the center to that small center shaft. When bimetal spring cools down, the flat metal piece slides over one hole at each end. That will force the friction disks to push the oil in a donut shape chamber thus letting the fan almost free.

When engaged the clutch never locks because it is oil between friction disks.

I took one apart years ago by curiosity. I though it was a smart desingn.

I do not recommend someone to rebuilt one.

When looking for a used one you should bring a flat screwdriver(quarter inch blade) and attempt to turn the center shaft no more than 1/8 of a turn. You can pry near the center shaft. That will confirn that the center shaft is not frozen with corrosion and that the bimetal spring is calling back the center shaft to the closed position. If the center shaft is not spring loaded to the cool position then the spring is defective. A stucked open valve engages the fan at all time, it is very noisy at high engine revolution not to mention highway driving.

The fan is operated by a a viscous fluid inside the clutch. The exterior bi-metallic element is for valving and the work is done by the viscous coupling between the shaft and the fan. This fluid can leak out or simply loose it's viscous properties after a while. The viscous fluid is an oil base material that gets more viscous as the temperature rises. Once gone, you need to replace the whole thing.
I had to replace the orig one on my 245 last summer. It wasn't too bad, but a used one from the older B21F 242GT engine that I had works a lot better. More drag on the engine, but it provides better cooling. I have an elec fan that I got from a 940 at a P&P yard for $50 that may go in, but the car runs pretty well for me to mess with it any more right now. If your in a hot climate (like TX), I would not recommdend the elec fan, becasue the viscous fan cools better and is more reliable. In Canada, you may want an elec if it's easier to find.
I think the OEM fan & clutch are ~$65 USD, sold as one piece from aftermarket suppliers. The older one like I have, is a two piece aluminum fan that has a replaceable clutch unit, so you may want to find one of those.
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'89 245 Sportwagon, '04 V70 2.5T Sportwagon

If you put in an electric from a 940 or elsewhere, doesn't it need a thermostat to switch it on and off?

Anyone have details on setting that up?

The 940 n/a in '94 &9 5 was the only B230 engine that came with an electrically controlled 'smart' fan & controller without an engine mounted viscous clutch fan.
All the Volvo B230FT's had the electric fan as an auxillary fan, and in their wisdom Volvo would never use only an electric fan on a turbo, unless of course they had no other choice for FWD vehicles. The poster below describes a thermostatic switch located in the lower radiator hose. This was used only on a B21FT turbo as an axuillary fan and the stock switches trip the fan at much higher temps than the engine should see for an electric fan only setup. The lower radiator hose is after the radiator cooling takes place, and the temps for normal running should be from the top hose or on top of the radiator.

The 940 n/a system has a fan mounted behind the radiator and two stage control relay next to the battery that is tripped from a two pole temp switch located in the top left side of the radiator. The whole fan & shroud assembly (which btw needs to be cut down to fit the 240 or pre '90 740, but will fit any late 740 & 940 radiator),sensor,control relay,main relay that controls cooldown after the car is switched off (in the fusebox behind the ashtray) and wiring harness should be taken from the donor car to make it work. The first stage is tied into the A/C compressor wire, lower temp switch, as well as the low speed setting on the fan. The high speed fan setting should be tied into the high temp sensor as well as the coolant temp sensor (via signal from the ECU) and high speed setting on the fan.
Some aftermarket fan control relays a can do the same thing, but they're pretty expensive. This system is a completely different beast compared to the fan & relay systems put onto cars that have the auxillary fan mounted in front of the radiator. I'm not sure but I think this same system is used on the 960's.
I tested this set-up off the car with a sensor that came mounted into the new Nissen tripple row radiator that I have, that came with the radiator, and it worked fine, but hooked up only to the temp sensor pins one at a time. In theory it will work great, and even puts out a lot more air flow than the engine fan when on the high speed setting. Obviously it is a PITA to hook up properly, so it sits and waits.
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'89 245 Sportwagon, '04 V70 2.5T Sportwagon

...the same as described for '94/

You could use a thermostat. There is a pipe with a bung welded onto it to accept the thermostat. It goes in line with the radiator hose. I do not remember which one . . . upper or lower. Everyone of those thermostats I have seen at the wrecking yard have failed. I suspect they would not be too reliable.

Optionally, you could use a Bosch 12V30A Solenoid and a switch. Holding it in your hand, with the spade termianals facing you: #3 Fuse Yellow Wire to the single vertical terminal, White Wire comes off the Air Conditioner Thermostat that has the aluminum tube coming out the top. It is the power wire and connects to the left parallel vertical terminal, Green Wire is power to the fan, and connects to the upper horizontal terminal, and the Black Wire is Ground, and connects to the right parallel vertical terminal.