radiator ooling fan

Post by **autojohn** » 15 May 2008 09:45 am

I have volvo 340 with rad fan and I need a thermal switch replaced. The one I have seems to be `intermitant` in that when my dash indicator shows about 185 F and I tap the rad switch, it sometimes works, but not every time,
I removed it and connected my multi meter to it then placed it in a cup of boiling water, and within about 5 seconds it worked.
I then replaced it in the rad and run the engine up to about 195 + and it wouldn't work even when I knocked it.
I bypassed the switch and the fan worked fine.
Any ideas on what I should do now will be very much appreciated.
By the way, does the power to this switch go through a relay? I do realise this question re the `relay` has no bearing on my problem, but I just thought that maybe there are burnt out contacts in the `switch` through DC surge

Post by **pettaw** » 15 May 2008 06:33 pm

I would just buy a new switch, they're not too expensive, about 20 quid I think.

One other thing I would just give the contacts both on the switch and the connectors a good clean out. They might just be corroded.

Post by **autojohn** » 15 May 2008 10:01 pm

pettaw wrote:I would just buy a new switch, they're not too expensive, about 20 quid I think.

One other thing I would just give the contacts both on the switch and the connectors a good clean out. They might just be corroded.

Thanks for the reply mate, But the switch is srewed into the rad and the contacts are sealed. The wireing is new with new spades.
I am trying to scource one tomorrow. Thanks again regards, John

Post by **pettaw** » 15 May 2008 10:17 pm

I didn't mean the internal contacts on the switch, I meant the spade connectors you plug the connections into, they often look a bit green to me and a good squirt of contact cleaner does no harm.

You say the wiring is new with new spades. Did you put the spades on yourself? If not the crimpy ones you get from Halfords etc aren't the best and corrode again pretty quickly from my experience, not to mention pulling off all too easily so if you haven't replaced them yourself it may be worth replacing them again.

Good luck with sourcing a new switch, the volvo part number is 3286641. It looks as though Eurocarparts has them in stock too, cost 8 quid.

Post by **autojohn** » 16 May 2008 04:28 pm

Thanks again `Petaw` I contacted Eurocars with that part number you gave me and they are getting one in stock for me tomorow Satuday.
I did do the wiring and fitted thouse pre insulated spades but I have ,on your valued advice, fitted two new ones.
I will keep you informed of any progress. Kind regards. John

Ps; I don't suppose you happen to know what the running tempriture for the rad is?

Post by **pettaw** » 17 May 2008 07:58 am

Running temp for the rad, erm, the engine running temp is approx 90-95, but the thermostat is quite low down on the rad. From memory its an 85 degree thermostat, but it'll have it stamped on the side of it somewhere.

Post by **autojohn** » 19 May 2008 08:45 am

Hi Pettaw. I got the new stat switch and you were right in that the deg's were stamped on the unit...87 -82 c. I'm assuming the two that have a 5 c difference is of no consiquence to the out come. So I was correct in my earlier thinking that 180 - 188 f on my dashboard dial is where the fan should kick in then.
I would have expected that `Intermotor` parts would have put a new copper washer inside the box with the switch, knowing that it is always necessary to renew it when re-installing, but then again we live in a `modern? ` world where common sence is rare in business circles. Come to think of it, I have never seen a ``Common Sence` diploma on any business property wall

I ran the engine up to temp and it seems fine now thanks mate.
Now I am going to install the same set up in my JBA kit car which is fitted with a Ford 2.ltr `Pinto` engine, though the rad is slighty different in that , where the Volvo rad has the fan switch at the lower side of the rad, I can only fit it in the base of the Ford rad. But we'll see how it performs.
Take care Pettaw. regards. john

Post by **pettaw** » 21 May 2008 12:37 am

No probs, regarding the Pinto engine, you might need to buy a lower temp stat to get it to kick in at the right time. I would say that approx 80ish wouldn't be a bad place to start, but some experimentation is needed, cos there's quite a temperature differential across radiators.

Post by **autojohn** » 23 May 2008 09:12 am

pettaw wrote:No probs, regarding the Pinto engine, you might need to buy a lower temp stat to get it to kick in at the right time. I would say that approx 80ish wouldn't be a bad place to start, but some experimentation is needed, cos there's quite a temperature differential across radiators.

I have tried to get more info on the `Lower` temp stat you mentioned but no luck there.
I'm assuming you do mean the screw in one I have for the rad and not the main egine state? so I fitted the same type in the Pinto as in the Volvo, then ran it up to 185 deg and the fan kicked in.
So all seems to be fine though I can't test it on road because it is not taxed or insured and not likely to be by me because I am just waiting for the very long delay by the DVLA to post my details on their data base on line. If and when this happens the JBA clb will be able to advertise it on the club site because I will never be able to drive it again because of being house bound you see mate. Thanks for everything again. take care. regards. John

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