Reply
 
Thread Tools Search this Thread Display Modes
 
Old 09-24-2018, 09:07 PM   #1
1 Rivet Member
 
1987 34.5' Airstream 345
Sevierville , Tennessee
Join Date: Sep 2018
Posts: 10
Blog Entries: 1
Cooling Fan & AC Issue

My OEM electric cooling fan stops working when I turn my dash air conditioning switch ON. The motorhome will overheat in this configuration. When I turn the dash AC switch OFF the cooling fan starts running again and it does cool the motor. I can literally turn the cooling fan on and off by toggling the AC switch on the dash. The AC does provide cool air but I can not leave it on since it turns off the cooling fan. Any thoughts on how to fix this will be appreciated.
__________________

John P is offline   Reply With Quote
Old 09-25-2018, 01:20 AM   #2
Rivet Master
 
Boom Sounds's Avatar

 
1991 25' Airstream 250
Oxford , Oxfordshire
Join Date: Jun 2007
Posts: 898
Images: 5
Quote:
Originally Posted by John P View Post
My OEM electric cooling fan stops working when I turn my dash air conditioning switch ON. The motorhome will overheat in this configuration. When I turn the dash AC switch OFF the cooling fan starts running again and it does cool the motor. I can literally turn the cooling fan on and off by toggling the AC switch on the dash. The AC does provide cool air but I can not leave it on since it turns off the cooling fan. Any thoughts on how to fix this will be appreciated.
Your electric dash air con cooling fan is not the problem. It will help cool the motor, but as far as I am aware, it is entirely peripheral to the set up.

Have you serviced your radiator and specifically have you recently replaced your fan clutch? That would be my first port of call. The clutch runs in various speeds, at first, it is barely audible. At full pelt, it sounds like an airplane taking off in your coach and your temps should drop rapidly. Is it coming on at around 200 degrees? If not, it's duff. Buy a heavy duty replacement, preferably AC Delco.
__________________

Boom Sounds is offline   Reply With Quote
Old 09-25-2018, 06:09 AM   #3
1 Rivet Member
 
1987 34.5' Airstream 345
Sevierville , Tennessee
Join Date: Sep 2018
Posts: 10
Blog Entries: 1
Quote:
Originally Posted by Boom Sounds View Post
Your electric dash air con cooling fan is not the problem. It will help cool the motor, but as far as I am aware, it is entirely peripheral to the set up.

Have you serviced your radiator and specifically have you recently replaced your fan clutch? That would be my first port of call. The clutch runs in various speeds, at first, it is barely audible. At full pelt, it sounds like an airplane taking off in your coach and your temps should drop rapidly. Is it coming on at around 200 degrees? If not, it's duff. Buy a heavy duty replacement, preferably AC Delco.
This condition started half way through my last outing. We noticed the absence of fan noise and rising engine temperature. In an effort to reduce the load on the engine I turned off the AC. When I did the cooling fan turned on with its typical full roar. Turn on the AC and the fan clutch stops working. I suspect a bad sensor but I haven’t a clue where to look.
John P is offline   Reply With Quote
Old 09-25-2018, 06:18 AM   #4
Rivet Master
 
Boom Sounds's Avatar

 
1991 25' Airstream 250
Oxford , Oxfordshire
Join Date: Jun 2007
Posts: 898
Images: 5
Quote:
Originally Posted by John P View Post
This condition started half way through my last outing. We noticed the absence of fan noise and rising engine temperature. In an effort to reduce the load on the engine I turned off the AC. When I did the cooling fan turned on with its typical full roar. Turn on the AC and the fan clutch stops working. I suspect a bad sensor but I havenít a clue where to look.
The fan clutch is entirely mechanical and run off a thermal spring. There is no replacement sensor, you probably need to replace the entire unit. At first, they can just start to stick and not work effectively. Then they entirely give up. It is not the electric fan, it is the thermal clutch which is connected and drives the main five finned metal fan. It looks like this:

https://www.amazon.com/ACDelco-15-49.../dp/B000C9FD6U

That is not meant to be an exact parts match for your vehicle.
Boom Sounds is offline   Reply With Quote
Old 09-25-2018, 06:54 AM   #5
1 Rivet Member
 
1987 34.5' Airstream 345
Sevierville , Tennessee
Join Date: Sep 2018
Posts: 10
Blog Entries: 1
The cooling fan is electrical. It receives on/off input from both engine temperature and the AC system. This OEM electric fan clutch was installed about a year ago without issue. Google points toward a bad “trinary” switch of which I know nothing. I suspect there are several sensors and switches that might cause this. I am pretty confident it’s not the clutch itself since it does work when it receives electrical input. Puzzling.
John P is offline   Reply With Quote
Old 09-25-2018, 09:43 AM   #6
Rivet Master
 
Boom Sounds's Avatar

 
1991 25' Airstream 250
Oxford , Oxfordshire
Join Date: Jun 2007
Posts: 898
Images: 5
Quote:
Originally Posted by John P View Post
The cooling fan is electrical. It receives on/off input from both engine temperature and the AC system. This OEM electric fan clutch was installed about a year ago without issue. Google points toward a bad “trinary” switch of which I know nothing. I suspect there are several sensors and switches that might cause this. I am pretty confident it’s not the clutch itself since it does work when it receives electrical input. Puzzling.
I know nothing about electric fan clutches. I thought they were all thermal switches. I think we may be talking about different things. Has your coach had an aftermarket fan added in front of the radiator? Either way, if you have lost the sound like you are taking off in an airplane, then your fan clutch isn't working as expected and that is what will keep temps down.
Boom Sounds is offline   Reply With Quote
Old 09-25-2018, 01:21 PM   #7
Rivet Master
 
Churubusco , Indiana
Join Date: Nov 2017
Posts: 514
So the fan is spun mechanically, but the clutch is electrically actuated? I've not heard of that.

Regardless, you have an electrical issue. Step 1, check your grounds. More info on how this is all wired would help.


Welcome to the forum, by the way. More info on what rig you have?
__________________
1983 Airstream 310 Class A Motorhome
-Rob
Magnet18 is offline   Reply With Quote
Old 09-25-2018, 02:21 PM   #8
Rivet Master

 
2007 22' International CCD
Corona , California
Join Date: Jul 2013
Posts: 5,515
No, I think we're talking two different fans here.

1) The mechanically-driven fan on the engine is driven by a V-belt, is usually mounted on the water pump pulley, and the fan speed is controlled by a thermally-controlled "viscous coupling" that allows the fan to slip to a lower speed when the air passing the coupling is cool, and gradually locks up when the air around it is hot. There is generally a bi-metal spring on the front of the coupling assembly (also called the fan clutch) that is typically aluminum colored and has fins cast into it to cool the viscous fluid that controls speed. The bi-metal spring also controls final fan speed. These assemblies have non-rebuildable moving parts and bearings inside them, and they do wear out.

2) Many radiators have one or more auxiliary electrically driven fans to add cooling at slow speeds or when the Air Conditioning compressor clutch is engaged to get sufficient cooling air coming through the A/C condenser assembly, which is generally mounted in front of the engine cooling radiator. These fans also may have an electrical thermostat sensor in the liquid coolant plumbing somewhere. They generally run at a fixed speed when energized. They also tend to wear out non-rebuildable bearings and internal parts as well.

What's NOT making sense to me is the increased noise when the Air Conditioning is turned off. Sounds sorta backwards to me. The real question is what's making the noise..the mechanical fan, or the electrical fan? Need to figure that out.

Note that the mechanically-driven fan may not be sufficient to keep the engine cool in slow traffic or with the A/C turned on. That is where the electrical fan is designed to help. Note that BOTH fans should be moving air through the radiator from front to back when they are spinning. Some have noted that the electrical fans have tried to move air the wrong way--possibly because of a wiring error at some point. Something else to check...
__________________
Rich, KE4GNK/AE, Overkill Engineering Dept.
'The Silver HamShack' ('07 International 22FB CCD 75th Anniversary)
Multiple Yaesu Ham Radios inside and many antennae sprouting from roof, ProPride hitch, Prodigy P2 controller.
2012 shortbed CrewMax 4x4 Toyota Tacoma TV with more antennae on it.
rmkrum is offline   Reply With Quote
Old 09-25-2018, 02:34 PM   #9
1 Rivet Member
 
1987 34.5' Airstream 345
Sevierville , Tennessee
Join Date: Sep 2018
Posts: 10
Blog Entries: 1
Thanks for the comments. I loose the “sounds like an airplane taking off” noise when I push the AC ON button on the dash. The noise comes back when I turn the AC button OFF. I can literally engage/disengage the “airplane noise” using the AC buttons on the dash. This is a recent problem. I appreciate your comments. Thank you.
John P is offline   Reply With Quote
Old 09-25-2018, 02:50 PM   #10
Rivet Master
 
Boom Sounds's Avatar

 
1991 25' Airstream 250
Oxford , Oxfordshire
Join Date: Jun 2007
Posts: 898
Images: 5
Quote:
Originally Posted by John P View Post
Thanks for the comments. I loose the “sounds like an airplane taking off” noise when I push the AC ON button on the dash. The noise comes back when I turn the AC button OFF. I can literally engage/disengage the “airplane noise” using the AC buttons on the dash. This is a recent problem. I appreciate your comments. Thank you.
In which case, you are not referring to the mechanical fan clutch because that has no bearing on your dash air con setting or any electrical switches. My sense is that you have an aftermarket fan which makes the 'aircraft noise' you are referring to. This, as you say, functions in a particular way when your dash air con is engaged. I think that is conceivable.

If I was a betting man, I would wager a bet that your mechanical fan clutch is not working correctly (per my original post) and not providing adequate cooling. Your electrical fan provides very limited cooling impact compared to the mechanical fan controlled by the thermal spring/fan clutch. When you hear that kick in (around 200-210), you will know what I am talking about. Temps should rapidly reduce to the stock 195 or thereabouts.

Why don't you leave your dash air con on, get her up to temps and see if the mechanical fan kicks in before you hit 210. You will hear it if it is working. If not, the likelihood is that you have a faulty mechanical fan clutch. The good news is that it is a relatively cheap fix and DIY job if you like that kind of thing.
Boom Sounds is offline   Reply With Quote
Old 09-25-2018, 06:47 PM   #11
Rivet Master
 
Churubusco , Indiana
Join Date: Nov 2017
Posts: 514
First things first, you need to know what your actual problem is before you try to fix it.
Do some tests with someone else flipping the AC switch inside while you look around at the fans, and see if what you think is happening is actually happening. Both with a cold and hot engine.






Assuming what I think is happening is happening, (your engine electric fan shuts off when the AC turns on) it could also reasonably be that your AC fan and electric fan temp sensor share a ground, and it started getting corroded. When the dash AC fan comes on the current through the bad ground forms a voltage that messes with the temp sensor for the electric fan.
__________________
1983 Airstream 310 Class A Motorhome
-Rob
Magnet18 is offline   Reply With Quote
Old 09-26-2018, 01:05 AM   #12
Rivet Master
 
Boom Sounds's Avatar

 
1991 25' Airstream 250
Oxford , Oxfordshire
Join Date: Jun 2007
Posts: 898
Images: 5
You may well have two separate problems;

1) Your dash air con system is not operating as expected:
2) Your Motorhome is overheating.

It's conceivable that they are related, but if you are constantly getting above normal operating temps (200), then you probably have two seperate issues. In my view, I would address any issues with overheating as they will cause costly repairs to the engine and tranny in the long run. For info, dash air con inoperability is probably second only to people's door bells not working on this forum....

Issue 1: The dash air con system is a mix of Airstream and Chevy installed parts. Your coach manual will set out the differences. It's not uncommon for people to mess around with the stock set up and add additional electrical fans to aid cooling, so probably worth establishing whether you are stock or not. If we are referring to the stock set up, I would refer to the following post (94) in the sticky which might help.

http://www.airforums.com/forums/f311...ml#post1895608

This will guide you to the relevant Chevy service, repair and electrical garage manuals, which should set out in detail the correct test procedures for the Chevy installed components of the front air con.

For info - this fella is meant to be good for spare dash parts/knowledge http://soldbyrichard.com/rvacheaterparts.php

Issue 2: If you are regularly getting above normal operating temperatures, you need to establish the underlying cause and, in my view, it's unlikely to be with your dash air con set up. I set out how you can test the mechanical fan clutch which is a common cause of overheating, but there are obviously others. You can find out more on that in service manual links I posted or google the site. Others e.g. Bob and Wayne have upgraded radiators and/or mechanical fans with seemingly good results, so if you find your overheating is not the fan clutch or your dash air con, it would be worth your time reading their posts which might provide some useful information on repairs and fault finding......or just stick it into a good service centre.

I hope this helps.

all the best
Nick
Boom Sounds is offline   Reply With Quote
Old 09-26-2018, 06:58 PM   #13
1 Rivet Member
 
1987 34.5' Airstream 345
Sevierville , Tennessee
Join Date: Sep 2018
Posts: 10
Blog Entries: 1
All good comments. Thank you. I will do some testing/troubleshooting and share the results. To clarify, this is a recient condition that started 75 miles ago. Prior to that this was not an issue. Thanks again for all the comments.
John P is offline   Reply With Quote
Old 10-01-2018, 08:45 AM   #14
1 Rivet Member
 
1987 34.5' Airstream 345
Sevierville , Tennessee
Join Date: Sep 2018
Posts: 10
Blog Entries: 1
https://photos.app.goo.gl/aqHJxHKpoDs2kRWu7
__________________

John P is offline   Reply With Quote
Reply


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Air Conditioning cooling issue Neil Archer Land Yacht/Legacy Motorhomes 14 10-04-2016 10:48 AM
domestic rm 60 cooling issue batt Refrigerators 0 07-25-2010 11:09 AM
cooling fan ?? kepko Land Yacht/Legacy Motorhomes 4 08-10-2008 10:50 AM
Auxiliary Electric Engine Cooling Fan cooperhawk Airstream Motorhome Forums 8 02-25-2007 07:18 AM
Electric Cooling Fan Settings rdm Mechanics Corner - Engines, Transmission & More... 1 07-12-2002 06:29 AM


Featured Campgrounds

Reviews provided by

Disclaimer:

This website is not affiliated with or endorsed by the Airstream, Inc. or any of its affiliates. Airstream is a registered trademark of Airstream Inc. All rights reserved. Airstream trademark used under license to Social Knowledge LLC.




Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -6. The time now is 10:55 PM.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2018, Jelsoft Enterprises Ltd.