When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
96 cab overheated. Exposed deterioted heater core connections at fire wall. Replaced heater core. Now it still overheats. Fans don't run. No heat in cabin. When engine gets to temp, top radiator hose gets hot, bottom one gets warm. Heater core hose on driver's side gets warm. Other one not so much. Turn on AC and the driver's side fan runs. PO replaced radiator, water pump, timing belt and tensioner. They maybe have 5000 miles use. Electrical connector at bottom of rad seems solid/not deterioted. Is this a stuck thermostat problem? Or something else. Appreciate any insight.
96 cab overheated. Exposed deterioted heater core connections at fire wall. Replaced heater core. Now it still overheats. Fans don't run. No heat in cabin. When engine gets to temp, top radiator hose gets hot, bottom one gets warm. Heater core hose on driver's side gets warm. Other one not so much. Turn on AC and the driver's side fan runs. PO replaced radiator, water pump, timing belt and tensioner. They maybe have 5000 miles use. Electrical connector at bottom of rad seems solid/not deterioted. Is this a stuck thermostat problem? Or something else. Appreciate any insight.
Sounds like a lack of circulation. Thermostats do stick. I've had them stick closed before
Do a thorough job..it may take a few attempts....my V6 takes a while..the engine block has a hard time getting the air out. Don't know why..except the "jiggle valve" in the thermostat really dosent work that well passing air.
We've run it up to temp several times, then letting the pressure out of expansion tank. Also ran once with tank cap off, at 2000rpm, to let air out. Have not tried to bleed with valve that's in the heater core line. Kind of don't want to mess with that because it's so old. Any other way to effectively bleed air? Hoping not to have to do thermostat. Sounds like it's a big pita.
bleeding the system is a pain..but needs to be done
If your not bleeding air from the cooling system up at the bleeder valve..there still is a very big air bubble in the cooling system. The water pump won't push air..and your thermostat will not open for a while till things get very overheated.
That heater hose bleeder is the highest point in the cooling system and you need to get the system bled..before you blow a head gasket or some other bigger headache.
If you are fearful that the bleeder screw is fragile then loosen the hose clamp and slide the heater hose slightly off the plastic heater core fitting..not all the way..just barely enough to let some coolant out while the engine is running..let it spit out coolant and air till all the air is out. and slide the hose back and tighten the hose clamp.
Be careful..that coolant gets hot very quick and the burns are painful..use some protective gloves or some handy kitchen utensils to move the hose around...that's why Audi has the bleeder valve..to avoid you getting hurt.
It was a leap of faith to install a Renault part..but it works and a better idea than the plastic. Don't tighten the fitting too much..just snug it down.
Ok. Here's where we are after today. Progress! Lots more bleeding of the system, and we have heat! Feeling good. Full circulation now, and thermostat must be working. But low speed fan still not working. Jumped the temp sensor switch, and hi fan worked, low(pass side) still did not. Check relays next. Surprise! Both low speed fan relays are missing. (See pics). Next wanted to test low fan at the switch to see if the motor worked. Come to discover the low speed fan is disconnected, wires tied off and hanging loose (More pics). Connected the ground wire for that fan to the ground for the high fan, and jumped it from the battery, and the low fan spins. So, I guess I've been driving it with only the high speed fan working. And it did turn on appropriately all summer when the engine needed cooling. So, #1, where the heck are my relays and why were they removed? #2, What's failed so that the high speed fan doesn't kick on now? #3, I assume I should have both fans working, so do I get new relays and which ones do I need? And #4, where should I connect the low speed fan positive terminal? Mystery.
Looks like only the missing relay image loaded. More available if needed.
IMG_6479.jpeg
IMG_7541.jpeg
IMG_2094.jpeg
IMG_3606.jpeg
IMG_8636.jpeg
There is a "resistor board" on the drivers side under the front where the positive sides for the fan motors connect. Don't have a picure..maybe someone has a link.
The relays under the hood..if you look under the fuse box cover it should indicate what relays go where...If not..here you go.
Upper left is relay #1..then counting to the right to relay #6
Lower relays starting at the left #7 through #11..#8 relay is blank.
Fuses at at the bottom.
Relay # 11 is a fan control relay..I think that one is the A/C super low speed fan
Relay #2 is the second speed fan
And under the driver's side kick panel there are some more replays..#11 on that group is the third speed fan relay..which is working based on what you have going on.
The resistor pack you have a picture of has three connections..the wiring diagram published is incorrect as it shows two.
The bottom connection on the resistor pack should be hot 12v with the A/C on.
The middle connection should be hot 12v with the second speed fan relay/radiator thermo switch Brown/white wire grounded to brown.
The top connection is the third speed 12v hot directly to the fans when the Brown/blue wire is grounded to brown. There is a cluster of wires there including the two red wires directly to the fans and the red/black wire to energize the fans at third speed..
(do check and make sure the brown wire on the thermo switch is a good ground too)
Those connections on the resistor pack are pretty grungy/rusty..they need to be cleaned up.
If you remove the plug from the radiator thermal fan switch..down at the bottom of the radiator..pullback the rubber boot..there are three wires.
Brown..ground
Brown and white..second speed fan (not the same as the first low speed fan with the A/C on)
Brown and blue ..third speed fan
Make a jumper with some wire and 1/4 in blade connectors..then bridge the thermo fan switch connections brown/white to brown...this should kick in the second speed fans..the fans you do not have working. The second speed fan relay is #2 which looks like it is missing. The ignition must be ON too.
Be careful working around the fans doing the test.
I have seen where someone in the past miss wired the resistor board and the second speed fans would be wired for the high speed position on the resistor board..it fries the second speed relay and cooks the wiring under the fusebox as the draw is way too high for that circuit.
Try a known good relay in position #2 and bridge the brown/white to brown wires at the radiator thermo switch..see what happens..
11-06-2014, 07:40 AM
Cabrio still overheats. Help please.
