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1998 Caravelle 2.6 fan not coming in
Posted: Tue Jun 04, 2019 7:23 am
by Bozwel
Hi Everyone,
I bought a 1998 2.6 Exclusive and the previous owner was running a manual switch to the radiator fan. The fan is running on high speed only.
I started to read up on this and how to fix it to standard way. I now understand that the fan has two modes and fan might be linked to A/C etc.
What I have done so far to try isolate the problem:
- I changed radiator fan switch
- I changed relay (number 7)
- I checked water circulation, (both pipes get hot at the radiator side, meaning hot water is being sent to the radiator and hot water returned to the engine as there is no cooling). This test I concluded that thermostat is opening
- I had the radiator flushed
Still with the above fan does not kick in automatically.
Any advice on how to proceed here.
Thanks,
Bozwel
Re: 1998 Caravelle 2.6 fan not coming in
Posted: Tue Jun 04, 2019 8:28 am
by Bozwel
Further tests:
- I noticed that when I switch on A/C the fan kicks in.
- I also noticed that though the water pipes get hot, the radiator only gets hot on one side where the pipes are and stone cold on the thermostat side.
Re: 1998 Caravelle 2.6 fan not coming in
Posted: Tue Jun 04, 2019 8:32 am
by Terry Phillips
On the radiator there is a thermo switch that has two or three wires bridge those wire at the switch if the fan works on 2 speeds then that radiator sender unit needs replacing.Just make sure the fuses are OK and the new sender unit has the correct temperature for that vehicle I got a switch that came on early and goes off late.
Re: 1998 Caravelle 2.6 fan not coming in
Posted: Tue Jun 04, 2019 10:07 am
by sean
You need to diagnose the problem by testing strategic points, don't just replace parts by guessing.
How sure are you the fan should be switching on? It only switches on low speed at 92 degrees and high at 98 degrees. If the radiator temp is below that, the fan wont switch on.
I would start by testing the low speed fan resister. It sits behind the drivers side headlight on SA build T3 kombis. Remove the headlight and test the resister. If the water temp is hot, you should have power in on the resister and power out as well, but at a lower voltage. If you have power in, but no power out, the resistor is burnt out. You can purchase a new one from VW. It has a different plug, but you can adapt it.
This is however for the low speed fan only.
If the low speed fan circuit is dead, you should still have the high speed engage when the water gets to over 98 degrees. This is normally on the first line on your heat gauge.
As Terry mentioned, it can be the fan switch on the radiator which controls the high or low, but sounds like you have replaced that already.
How are you testing water temperature? You must test on motor and radiator. You can have the water boiling on the motor side but nothing on the radiator if its not circulating.
Re: 1998 Caravelle 2.6 fan not coming in
Posted: Tue Jun 04, 2019 10:24 am
by Bozwel
Terry Phillips wrote: ↑Tue Jun 04, 2019 8:32 am
On the radiator there is a thermo switch that has two or three wires bridge those wire at the switch if the fan works on 2 speeds then that radiator sender unit needs replacing.Just make sure the fuses are OK and the new sender unit has the correct temperature for that vehicle I got a switch that came on early and goes off late.
The radiator switch has 3 wires. When I bridge it ts only works on high speed.
Re: 1998 Caravelle 2.6 fan not coming in
Posted: Tue Jun 04, 2019 10:54 am
by Bozwel
sean wrote: ↑Tue Jun 04, 2019 10:07 am
You need to diagnose the problem by testing strategic points, don't just replace parts by guessing.
How sure are you the fan should be switching on? It only switches on low speed at 92 degrees and high at 98 degrees. If the radiator temp is below that, the fan wont switch on.
I would start by testing the low speed fan resister. It sits behind the drivers side headlight on SA build T3 kombis. Remove the headlight and test the resister. If the water temp is hot, you should have power in on the resister and power out as well, but at a lower voltage. If you have power in, but no power out, the resistor is burnt out. You can purchase a new one from VW. It has a different plug, but you can adapt it.
This is however for the low speed fan only.
If the low speed fan circuit is dead, you should still have the high speed engage when the water gets to over 98 degrees. This is normally on the first line on your heat gauge.
As Terry mentioned, it can be the fan switch on the radiator which controls the high or low, but sounds like you have replaced that already.
How are you testing water temperature? You must test on motor and radiator. You can have the water boiling on the motor side but nothing on the radiator if its not circulating.
Thanks for the input Sean.
I had the car basically overheating but fan doesn't come on. I will try locate and test the low speed resister.
This is what I noticed this morning and think it might be the root cause.
The radiator gets hot on one side and remain stone cold on the side of the radiator fan switch. (hence the switch is not getting any temp reading to trigger the fan).
Though both pipe lines in and out of the radiator are hot.
I think water is not flowing correctly in the radiator to the side of the fan switch.. So I think I should replace radiator.
Is my thinking correct.
Re: 1998 Caravelle 2.6 fan not coming in
Posted: Tue Jun 04, 2019 12:23 pm
by Terry Phillips
There should not be more than 15 deg difference between the top and the bottom of the radiator.I would send the radiator to Silverton let them see how badly it is blocked if it is the cause and check the thermostat is in and working.If the thermostat is not working then the radiator will do as you said hot one side.Check the water pump is pumping and I am not sure but did the 2.6 not have a electric water pump fitted in line.Cant be sure if there is one.
Re: 1998 Caravelle 2.6 fan not coming in
Posted: Tue Jun 04, 2019 6:35 pm
by retrovan
It is very simple, that if the radiator stays cold on one side, this means your thermostat does not open.
OR you have an air block behind the thermostat.
Take the thermostat out and test in boiling water, and watch as it cools that it closes.
If its an air pocket behind the thermostat due to oily antifreeze, drill a 2mm hole through the disk part of the thermostat, then the air can not get trapped behind the disk .
If air gets trapped behind the disk, there is no temperature in the air, so the thermostat will not open.by drilling the hole, the air passes through, and the water gets to the thermostat and it opens.
Herman