Radiator fan questions


Gary B. Dixner

New member
My 85 Westy temp runs steady at halfway mark while moving. When I stop the temp rises 'til fan eventually comes on. VW checked sensor and said it's okay. I notice if I just turn on the AC switch (not necessarily compressor) the cooling fan comes on. Is this an acceptable way to manually operate the fan for an extra margin of safety to guard against overheating?
 

Capt. Mike

Moderator
/infopop/emoticons/icon_frown.gifThe fan coming on only when the temperature rises above sensor trip point is designed in. Due to typical operating temperatures, it's also set up to come on with A/C.

However, I think you are placing too much stock in what the gauge reads. It's reacting perfectly normal. If you read your manual, you will see that temporary climbs near maximum gauge reading are acceptable, and of concern only if the overheat light comes on, or it does not come back down quickly underway.

Long periods of idling with the A/C on (ala big trucks) in NOT designed into the cooling system, but stop & go traffic bump-ups usually won't hurt. Watch your coolant level; if you are not overflowing the resevoir catch tank, chances are you are not overheating the engine.

However, I will add this may also indicate you're due for a complete cooling system check & flush. That's an every-2-year job (maybe not the flush if you are in good condition and have been doing it regularly) and can restore a good bit of efficiency. Under the TIPS forum in "Archives", there is a long thread on "Coolants, clearing the muddy waters". It has suggestions on flushing and tips on how to do it right since complete draining of a Westy is next to impossible.

Running the A/C to get the fan is not practical; and the fan is tied to the compressor, which means it will cycle on as the A/C thermostat calls for it. If you feel you must do it, consult a mechanic with excellent electrical knowledge and add a manual switch with relay (and indicator light) in parallel with the automatic thermostat controlled switch that is independent of temperature .

[This message has been edited by Capt. Mike (edited 05-29-2000).]
 

Capt. Mike

Moderator
Transferred from another post to consolidate subject.

Radiator fan switch now working

walkabout, Junior Member, 03-18-2001 06:19 PM

83 1/2 Westy, 140K miles. Previous owners had bypassed the radiator fan thermo switch. It ran anytime the key was turned. I replace the switch and made sure that the fan ran on high and low speed by jumpering across the contacts on the plug that goes on the switch. However, the fan never came on even when the engine had idled for an hour or more. Any suggestions?????

Capt. Mike, Moderator, 03-18-2001 10:23 PM

Have you checked the radiator fan relay?
The Bentley wiring diagram, pg 97.59 shows the thermo switch feeder the relay, not the fan, so a bad relay would keep the fan from working even though the fan itelf was OK.
 

Capt. Mike

Moderator
Transferred from another post to consolidate subject.

2 speed fan

dub green, Junior Member, 04-09-2001 06:35 PM

I tried to search the archives on this but the server seems to be down. anyway living in the south the fan seems to kick in to a extra high speed sometimes especially with the A/C on. Is this normal, my temp light does not come on and I just got a coolant change. Any help out there? Thanks,
PS: About to travel to Florida so I need some help!
 

Capt. Mike

Moderator
Always give year & model. I'm assuming a water-cooled Vanagon.

If you look at your Bentley wiring diagrams for the A/C starting on page 97.137 depending on your model, you'll see the A/C kicks in the higher cooling fan speed to compensate for the added temperatures created by the condensor. This is done regardless of the signal sent by the engine coolant sensors.
 

Capt. Mike

Moderator
Transferred from another post -- duplicate thread.

Tim Hannink, Junior Member, 04-10-2001 09:11 AM

Yes, this is normal operation of the radiator fan. The thermoswitch on the front of the radiator behind the lower grill controls when the fan comes on for both speeds. Typically in the Florida summer (March to October ), it will turn on high speed on after sitting in traffic for a couple of minutes with the A/C on. It should shut off after you start moving again. Mine came on last Sunday after sitting at light for two cycles with the air on.
 

Capt. Mike

Moderator
Transferred from another post to consolidate same topic.

Radiator Fan

alfa87 Junior Member # 854 posted 06-20-2001 12:17 PM

My newly aquired 1989 Syncro has developed a problem with the radiator fan - it stopped working! I have done the obvious: checked the fuse, checked the fan itself by connecting wires from the temp. sender in the lower driver's side corner of radiator. When I performed this check, the fan would kick into high speed, but there was no low speed. I'm not sure that that is normal. The fan does not operate when the A/C is turned on, which, as I understand it, the fan should automatically come on when the A/C is turned on.

As the temp. gauge begins to climb towards the top it sounds as though the fan kicks on high for about 5 seconds but then it cuts out. The needle continues to climb until I am forced to turn all the heat on. Any help would be greatly appreciated before I cook myself, my family, the engine or all of the above.

dajabr Member # 774 posted 06-20-2001 02:46 PM

I have been having similar problems, but originally I believed they were realted to a faulty instrument console. So far have flushed system, replaced sensors and instrument console but it goes to overheat, fan USED to kick on only at very high temp and at high speed, never low, just like you. Now doesn't come on at all... will post when I find the solution. See my posts in gauge operations for the background story...

alfa87 Junior Member # 854 posted 06-20-2001 04:08 PM

dajabr - I am wondering if it is the relay. My understanding is that there is a relay for the system (I have Bently on order, so I should have a better idea soon). I was given a part number from a VW dealership #321-919-505A. I want to get a better notion as to whether this is the culprit before I sink $30 bucks into a part that may not need to be replaced. Perhaps someone out there has experienced a similar malfunction.

dajabr Member # 774 posted 06-21-2001 10:44 AM

It sounds like we have the exact same or very similar problem.

I had all my fuses and relays checked when I first bought the van, had to replace 3 fuses, relays all looked good. However I'm going to go ahead and have the relay replaced, now simply because there's not much else to replace that hasn't been already. I'll let you know if that works. Try cleaning off the sensor in the rear tank and then overfill the tank, right to the top. The excess will go into the blow over tank if it has to. Also keep checking for air in the system, mine had several bubbles even after a pro flush. Smack the big radiator hose a couple of times when it gets hot and see if it loosens some bubbles into the tank. It might have helped to get those out, but my (new and OEM) tank split before I had the chance. Good luck, will let you know how this works out but it may not be til next weekend or so when I get back from a business trip. Dan

Alfa, just picked up my van. Apparently only the fuse in the relay was replaced so now my fan kicks on at high temp, but am just back to my old position of running hot. I am going to do some research and maybe relay work to find out. Considering the fan works and the whole system has been done over, I will replace the relay, if it is bad it may stop blowing the fuse. Suggest you do too becuase your symptoms are so similar, would save you all the other stuff I have done. Am a little dissapointed in the mechanic because there has been no progress on this, am back to where I was months ago, even though he claims it's "fixed". Wish I had the time to do this myself. Will see... Dan

alfa87 Junior Member # 854 posted 06-29-2001 04:02 PM

Dan, what model and year is your van? Also, which relay(s) do you plan to replace. It looks as though there are several posibilities. There is also some kind of resistor behind the driver side headlight (at least in an '89 Syncro)that is tied into the cooling fan system. You may want to take a look at that too.

dajabr Member # 774 posted 06-30-2001 01:27 PM

84 Westy. Am going through my receipts to find which of the various similar named relays and sensors have already been done. Bentley has provided a research project, am trying this too www.vanagain.com/How2fan.htm even though sending unit has already been replaced. Will have to get back to you.

dajabr Member # 774 posted 07-16-2001 11:10 AM

Just got back from a beach trip in the Westy. Found that it randomly runs hotter on some runs, cooler the next. Fan was reliable except for one time. Still studying up on this, getting more mysterious. Am going to have the thermostat replaced in case it's sticking, see what happens. Also, still looking for (another) test/replacement console so I can have reliable gauges, and make sure the red light only blinks when it has to, will help to diagnose if it's not blinking ALL the time.

[ 07-23-2001: Message edited by: Capt. Mike ]
 

turg

New member
1991 Westy GL. Every time the radiator fan comes on it always does at high speed. Do I have to replace the thermostatic switch or relay or both?
Best regards.
 

Capt. Mike

Moderator
Which is broke? You can test both. Bentley 19.12 tells you how to test the switch and relays are easy to bench test with a 12v battery and an ohmeter. The wiring diagram shows the terminal numbers and current flow.

Don't rule out the motor or wiring. The motor has 2 speed shunts and failure of the low speed one would give your symptoms.
 

tonynbarb

New member
I have an 87 Westy. The high speed fan kicks in at the point where the low speed fan should be kicking in. For the most part the low speed fan doesnt kick in at all. Do you have any ideas, thanks.
 

Capt. Mike

Moderator
Test it. Specs for both stage I & stage II are in the Bentley, section 19.12. Includes both cut-in & cut-out temperatures. If switch is OK, then one speed of fan motor is probably gone.
 

tonynbarb

New member
Like I posted before, the second fan ( the loud one) would kick in in place of the first fan. Thanks to a reply on here I figured it was either the thermoswitch or the fan motor. Since the thermoswitch was only $12 I decided to replace it. It looked as though it took a special deep socket to replace it which I didnt have and I was worried I would lose a lot of coolant when replacing it. I took the van to VW taking advantage of a free oil change they were offering and they offered to replace the thermoswitch for $30. I decided to get it over with and have them replace it. It solved the problem. The fan is working normal.
 

JOHNWOLF

New member
Hello, I posted a question yesterday under this heading but somehow it appears to have disappeared. If it has been transferred somewhere else I can not seem to find it. I have a 1987 Vanagon GL automatic. My problem is that the radiator fan sporadically comes on when the engine is cold and will often stay on. Normally the fan would only turf on when the engine is being stressed or when stuck in traffic. In addition the temperature light is now turning on. The coolant is filled to the max, the temperature gauge is usually at the halfway mark and there doesn't appear to be any sign that the engine is overheating. I do have a leak from the head gasket but it only looses about three ounces every five hundred miles. I drove the van 15000 miles last summer without a problem. I did have my mechanic check it out, (prior to the temp. light turning on) and he didn't see any problem with the fan or the thermostat. He's a good mechanic but does not specialize in VW's. Any suggestions on where I should start would be greatly appreciated. Thanks. John
 

Capt. Mike

Moderator
Transferred to consolidate same topic.

Rickkel Junior Member posted August 08, 2002 02:37 AM

I have a 1987 Vanagon Westy with A/C and have some questions regarding the radiator fan. Mine stopped working - even with the A/C on which from the archives and personal experience should kick it on immediately when turned on.

I dropped the spare and attached 12 volt power to the bolts coming out of the fan and it turned on. I'm assuming this means the fan is okay, however I'm not sure which of the two speeds this would kick on with this test.

Since the fan doesn't come on at all when the temperature rises, I checked the fuse (which was fine). What is my next step? Do I just assume the fan temperature control switch behind the lower grill needs replacing? What about the cube in the fuse box (with a 53 on it)? Can that be tested? If so, my Bentley doesn't seem to give a clue as to how these items can be tested.

If the temp control switch needs replacing, is it just a matter of taking out the old one and replacing it, or does this mean a drain and refill of the radiator (with all the accompanying fun that entails)?

Any help would be appreciated. I've done a search in the archives, and although this topic has been discussed, the detail is sketchy and no troubleshooting issues/replacement procedures are revealed. Thanks for any help you can give.

George K.

TJ Hannink Member posted August 08, 2002 09:41 PM

Ken Wilford at www.vanagain.com has a test procedure for the radiator fan on his web page here: http://www.vanagain.com/How2fan.htm

The relays can be tested out of circuit with a 12 volt source and an ohmmeter, there should be a schematic of the relay printed on the side of the cover.

The thermostatic radiator switch is very easy to replace. Remove it with a properly sized deep well socket (I think I used a 1-1/16", take your new sensor with you to the parts store and check the size). If you switch them quickly enough, you shouldn't lose much coolant, I lost less than 1/4 cup.

Good luck,

Tim Hannink
Winter Park, Florida
Goldibox - 1987 Vanagon Camper, Wolfsburg Edition

http://home.earthlink.net/~tjhannin.../tjhannink"]http://photos.yahoo.com/tjhannink
Vanagon Album
http://groups.yahoo.com/group/wolfsburg_campers/


George K.
 

tonynbarb

New member
I have an 87 vanagon westy. A couple of weeks ago the battery went dead. Since the battery was several years old I figured it needed replacing. Several days later I became aware that the radiator fan was coming on and staying on. In other words you would get home, go in the house and the fan would run till the battery went dead. I decided to start with the cheapest solution and that was to replace the thermo switch. To my surprise when I unscrewed the switch no water came out. The antifreeze (vw brand) had caked around the outlet forming a plug. I punched out the plug and replace it with a new thermo switch. This solved the problem with the fan. Not sure if the new switch solved it or clearing the plug. Note: I am not sure what the repair book recommends for removing the thermo switch, but I use a plumbing wrench ( not sure of the correct name) its a wrench used for under sinks to get to hard to reach places. This wrench works great for removing and retightening the switch.
 

Capt. Mike

Moderator
When you find a large amount of crud or caking like you describe, it indicates you are probably way overdue for a full flush, perhaps even a professional machine flush. If you have found a clog of that magnitude, it's possible there are others that, if not blocking the system, are at least inhibiting flow and causing hot spots. See the TIPS forum, "Clearing the muddy waters . . ." topic.

The sender should be removed with an ordinary metric wrench. Senders often have different sizes as compared to DIN standard nuts & bolts, but they will always be a straight metric size.
 

swilger

New member
I have a 1990 westy GL. My big ol' $500.00 cooling fan in the front comes on and stays on no matter if I have the acc. when I turn the key or if I start it up on a cool morning, etc... it pretty much comes on and stays on any way you turn the key. any ideas? Steven Wilger
 

Capt. Mike

Moderator
It's either miswired or you have a sensor problem. Testing and correcting either is addressed in other posts on the site.

Fan running should be independent of the ignition switch because it will run for a short period after shut-down to cool down a hot condition. The only accessory that overrides the cooling fan "off" settings of the other temps/sensors is the A/C. It turns the fan on to prevent overheating the A/C condensor.
 

solstice

New member
I have an 84 Westy.I was checking the fan by jumping the three terminals on the connector to the thermoswitch. I got one fan speed to work but not the other(not sure which speed works,sounds like maybe high). Before I replace the fan,I was wondering if there is a relay for each speed or only one for both speeds. Or possibly another solution.Any ideas?Thanks, Russ

_Radiator fan switch now working_

[This message was edited by Capt. Mike on May 31, 2003 at 07:15 AM.]
 
Howdy Campers: In my 84 Westjetta I've also lost the cooling fan. Not a real problen until crawing up hill on a dirt road. Have scoured the Bently's (97.59) electrical diagrams,alas I can not find where the "RAD FAN RELAY" lives! The ground, #13 is listed "behind the air vent. Seems like the first place to check if only I knew where. Any help is alway appreciated.
Steve
 

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