Pls help: cooling fans not turning on and low coolant warning
 

I'm hoping someone can point me in the right direction of what to look for. After putting up with the screaming banshee noises of a harmonic balancer that needed rebuilding, I took it out and shipped it off to Dale Manufacturing. (He does great work and has quick turn-around time.) While I had the balancer out I decided to replace my thermostat as I was pretty sure it had gone bad in the open position and I drained and refilled my coolant. Now I have everything back together I notice that 1) the cooling fans aren't turning on, 2) my low coolant light keeps coming on even though the reservoir is filled up to "MAX" and, 3) the car started overheating the other night while I was sitting in the drive through lane of a fast food place.

Things to note: I used regular green coolant which says on the bottle that it works in all cars mixed 50/50 with regular tap water. I see people on here talk about using distilled water but the manual just says regular water. Are either of these a problem? Also I don't really know how to flush the system so I just let it drain, filled it with water and ran it for a couple of minutes, drained it again and then filled with the above mentioned mixture. Is this a problem?

For the overheating and low-coolant: Are you SURE you plugged the fans and the low coolant sensor connectors in on reassembly?

Tap water vs. distilled water: Unless you have extremely hard tap water with lots of dissolved solids, it would have nothing to do with your overheating issue. This is more a long-term issue, by using distilled water, you are not introducing other minerals and substances that may degrade your coolant or precipitate out in small internal coolant passages or accelerate corrosion.

Your description of the drain and refill is a bit general, but I get the sense that you don't currently have a 50/50 mix aboard. Again, wouldn't cause overheating or low-coolant, but you may not have the low-temp protection you expect to have. Better check it with a hydrometer.

If memory serves, that is about a 12 Qt cooling system, and just draining at the radiator only yields about half that. So if you did one water-fill, run, and drain, then topped up with 50/50 mix of new, you have in rough numbers, 3qts of the old coolant(or 1.5 qts old coolant and 1.5 qts old water,) 6 quarts of water, and 3 quarts of the new coolant. The key question is how much undiluted new coolant did you consume when topping up, regardless of where/how you mixed in the water? or did you buy the pre-mixed stuff?

Also important is what color was the coolant you drained originally. Mixing different coolant types can result in forming a precipitate that can block the radiator and heater core.

As you drained the system it probably has an air lock.

Try bleeding the system again.

Try putting a live feed straight to the fans from the battery terminal by the fuse box

Cooling fans should run all the time. Stopped in a line would cause overheating if fans aren't running. Coolant level sensor float ring (inside tank) is probably stuck down (not floating), which triggers the warning.

Is it just colour or is it important to avoid mixing the OAT and other type of anti freeze, basically old style glycol based and new style ones?

I think the colour is manufacturer specific and may not always be a guide to teh type of anti-freeze.

Mike

drmike, that's what I was thinking about but couldn't recall the details.

First thing is to get the fans working. Double check the fan connectors. Check the fuses, F11 and F17 in the LH engine bay fusebox. Check that you have 12v on pin2 of the RH fan. Check the fan relay module below the left headlamp.

I can't tell you all how much I appreciate the responses. Having a problem that wasn't there when I started makes me feel like a real bonehead so thanks for the assistance!

I'm positive plugged the fans back in but I don't remember seeing low coolant sensor connectors. The fan connectors are the only ones I unplugged when I removed the fan ass'y. I'll double check the low coolant sensor connectors, though. Can you tell me where they are?

It took 8 quarts of 50/50 mix and then I topped it up with maybe a quart or less of water. I'll pick up a hydrometer and test it. Thanks again!

It appears that it was originally orange (it's still sitting in a bucket in my garage) but I had topped it off with green (and water) so kinda mixed. I guess it would be good to figure out how to do a legitimate flush. :icon_emm:

I wondered about the possibility of air trapped in there. Try bleeding the system or actually flushing it?

How exactly to I apply voltage to the fans? Are there directions for this somewhere?

Can I see this ring if I remove the cap and look in there? I'm not sure where it is.

I did check the fuses and they're good. I'll check for the 12v and the relay.

Thanks!

Without wishing to seem alarmist from my research I think orange and green/yellow is not a good combination no matter who makes them. I think a full flush and replace is in order which is a PITA but not that hard. Don't you just take the lower radiator hose off and stand well clear :) I did this on my Land Rover and did as you did collected the coolant to reuse when trying to get the injector pump working right. A big bucket did the trick then, not so easy with a low slung Jag.

Mike

You know how to take the connectors off because you already did that. Get a multi-meter and stuff the probes up the connector, switch the ignition on and see if you get 12v. But I am very simple minded about these things :)

Mike

Inside reservoir tank, the float is barely visible. Use a bright light, and a long screwdriver to gently free it up. It is a white ring that floats around the (external) sensor pin.

This is how I did it originally. I did have a bucket under the lower rad hose but the front end was on jack stands. Maybe the angle of the vehicle prohibited all the coolant from draining?

If I'm going to flush it though, wouldn't I need to do more than just let it drain like stick the garden hose in there somewhere? I just don't know where that would be.

Ok I just checked and I'm definitely getting 12v to the right side fan so why aren't they turning on?

Also I looked and I don't see any kind of ring in the tank. I see the housing that the sensor pin sits inside of but I don't see a ring.

The other thing is that the tank is empty again so I'm going to run out and buy some more coolant. This is getting to be very frustrating!

You must be seeing coolant on the ground, where is all going? I can tell you all the likely locations of the leak if you can get a good estimate of where it's dripping from.

There's a thermo switch on the radiator itself, left side, down low-ish on the tank. Make sure you didn't inadvertantly dislodge or damage the connector



Cheers
DD