Whether 1995 Audi 90 sport radiator fans pull in outside air or push out? The fans on my car take a long time to come on and then it takes forever to cool the radiator. They stay on in the city drivin

KANWARB
10

Asked by KANWARB Jul 08, 2012 at 01:41 PM about the 1995 Audi 90 Sport

Question type: Maintenance & Repair

14 Answers

wb6epp
710

Air is drawn in from the outside to pass through your raditaitor to cool. You did not state what the temp was running? Here is one of the biggest over looked area for over heating. Check your "Bottom rad hose. Try to pinch it shut. If you can, the hose is bad and shuting off the coolant to the engine. {meaning the hose is being sucked shut by the coolant demand.}

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KANWARB
10

The lower hose feels stiff. Temperature on highway stays less than half. Local, stop and go(through lights), it goes over half. The fans are pushing air out and this does not let outside air come in when car is in motion, resulting in temperature climbing up. The fans run in two speeds only. Not sure if they should run in three speeds. If thermostat is OK, it should take only a minute or two to reach oper. temp. in 95 ambient. It takes 10 mins. Where is the thermostat located? The A/C is not working. Did not find low side to charge. Does it require an adapter to charge factory 134A fitting. Thanks for you help. You gave me some hope on my 1995 Audi 90 sport.

wb6epp
710

Kanwarb: your fans should be set to draw air in, not push out!! At a certain speed the air from motion counter acts the fans pushing. This is the first to correct. Your thermostat is located under the the "Goose neck" { this is where the radiator hose connects the the engine}{this is the discharge coolant hose to radiator}. But it sounds like you are running at the right temps. if the guage is showing in the center. Stop & go traffic, the car will run a little warmer. Reason, you are trying to cool your car with the exhaust temps from the traffic, so ground temp is a little warmer. On a 134-A refrigerant system, the charge valve is larger that the pressure check valve. This prevents a bomb from going off in your hand. Yes the newer cars make it hard to find at times, but I tell you it is there.

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KANWARB
10

I really appreciate your staying with me through the problem. Please explain how can I reverse the air flow direction of the dual fan assembly radiator fans? Outside air wants to come in through radiator when the car is moving, but the fans are trying to push air out at jet speed, preventing outside air to cool the radiator. Only on highway speed the force from outside air becomes greater than that from jet speed turning fans, resulting in very slow cooling. Reversing fans' direction might be an immediate and the only solution. Kindly suggest.

wb6epp
710

Your fans is what is called a magnetic polarity. They can run in either direction. But first, are these the stock fans that came with Audi, or aftermarket? Are they in front of the radiator or behind? One way to tell, is the plug matching from factory wiring? For tests sake, unplug the fan. Use jumper wires to test for voltage. this requires you find the thermostat switch for the fans, normally located in the raditor. This also should have a plug. See if you can reverse the plug puting the postiive on the other side, which will reverse the fans. I hope you are mechanicly inclined, if not take it to a local shop to do this. Here is a quick explanation. When the key is turned "on", voltage will be applied to one side of the thermo switch going to the radiator. It is no more then a on & off switch, but requires the set tempature to close the switch, making contact and sending the voltage down to the fan motors, which in turn makes them run. My way to test is to make a jumper wire to bypass the switch on the radiator. This should start the fans running. Now you can see which way air is flowing. If pushing, the the positive wire needs to be changed at the fans. Sorry for the long answer, but need you to understand how the system works. Here is another question for you. Can you just turn the fan system around?

KANWARB
10

Your answer is not long, it is just sufficiently long to make me understand very well. Any shorter, I would miss out on crucial things. The fans are original equipment, behind the radiator. It is possible someone might have carelessly put the thermostatic plug backwards when it went for timing belt replacement, soon after I bought the car at 100200 miles(currently 100400). The exhaust smells bad, the car idles erratically. After driving a little while on highway, the check engine light comes on. I turn off the engine and restart it goes away and then comes on after a few minutes.

wb6epp
710

Sounds like you haven't had a tuneup in awhile. That would most likely take care of the eratic miss. Since I am not a Audi mechanic, do you have coils on each cylinder or do you have a distrubitor with plug wires? Do you have away to read the codes? Was your raditor pulled to replace the time belts? If so, the plug at the fan might be backwards. Anyhow, you need to draw air, not push it.

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KANWARB
10

Thanks for your reply. I'll have to check if it has a distributor or not. The six spark plug wires come and join to a device in front, which does not look like a round distributor. I guess they need to take off the radiator to change timing belt because of small clearance and the fans' location between timing belt cover and the radiator, it being not a transverse engine. It is 1995 so I doubt it has a port to read codes from. The decal on the hood says it is OBD 1 compatible. I will try to reverse the air flow direction of the fans soon.

wb6epp
710

you have a electronic distrubitor controled by your ECM. Which makes it easier to change the plugs. I would take a OHM meter and check the readings for your wires, or just change them if you have not tuned the car since you have owned it. I have a friend that has a Audi, and loves it, but his complaint is the high price to maintain it. Since I am 73 yrs. old, I don't work on them much anymore. But love to help out where I can.

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KANWARB
10

My dear friend, you really impress me with your such a positive attitude. I do not have words to express my gratitude. I hope you can feel it in my words. I had bought this car to give to my daughter after she graduated, thinking I could get it fixed. Got the timing belt changed, coolant replaced and oil and filter replaced. When I gave the car to the mechanic I had given him brand new spark plug wires, spark plugs and front strut cartridges and strut mounts that the guy gave me from whom I bought the car. After I got the car back, drove it occasionally for a few months and once opened the engine cover and saw the wires and plugs had not been replaced. The bolts on top of the struts were loose(the front end was making noise). Can you please tell me what should be the resistance of the wires?

wb6epp
710

That, my dear friend, I would have to locate my old book for that answer. But in general, you should see resistance & no open short {meaning no reading}. I believe I would ask the mechanic for my product, or check the bill, if charged, have him finish his job. I believe once the bugs are worked out, you will be satisified with the car.

1 out of 1 people think this is helpful.
KANWARB
10

Thank you so much. I'll check the wires soon and let you know.

wb6epp
710

How mechanical are you? Can you do a compression check? Since you are going to change the plugs, I would do compression check. The China guages will do for home purposes.

1 out of 1 people think this is helpful.
KANWARB
10

Yes, I'll buy one from Harbor Freight cheaply, and let you know of the results. Thanks for guiding me.

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