Author Topic: coolant light (Read 2983 times)

BellCityDubber · « **on:** July 05, 2007, 11:50:12 am »

Okay.... This is kind of a weird question, but here goes.

Every so often, I'll either be driving along, or I'll just be starting up in the morning. and I'll have my low coolant light start blinking at me. The first time this has happened, I pulled over, checked the bottle and it seems fine.

I'm going to try and replace the bottle but I have a few questions

1. The coolant sensor in the bottles are the same from the different sphereical bottles? Correct?

2. I replaced my oil cooler last year and I get a bit of black sludge in my coolant bottle... I assume that it would be messing with the sensor... perhaps?

Any other ideas? anyone?

burn_your_money · « **Reply #1 on:** July 05, 2007, 03:00:12 pm »

Mine does that after taking a hard long corner. I just turn my car off and back on (while I'm driving) and it goes off. I think I'm a tad low on coolant so when I take the corner it trips the sensor

BellCityDubber · « **Reply #2 on:** July 05, 2007, 07:37:02 pm »

Quote from: "burn_your_money"

Mine does that after taking a hard long corner. I just turn my car off and back on (while I'm driving) and it goes off. I think I'm a tad low on coolant so when I take the corner it trips the sensor

mine does that too.. only on this one specific offramp... (probally coz I'm just BAGGING on it)

.... but yea.. I cant figure it out...

I already changed the bottle once, but I have another bottle.. all with seperate part numbers... I'll change it and see what happens.

saurkraut · « **Reply #3 on:** July 06, 2007, 06:00:00 am »

Sometimes these things just lose thier minds. I have a '92 Passat that just blinks randomly, regardless of tank level, or even if the sensor is hooked up or not, and even with a paper clip shorting the connector. And i will admit that it really sucks to have a red light flashing frantically while your driving, but i haven't found an elegant solution.

i put a cluster in my '79 that has a level warning light. I just painted over it since i didn't have anything to hook it up to. At night I can see a slight glimmer as it occasionally sends a frantic warning of nothing in particular.

I think VW really dropped the ball on this measurement. There must be some logic crap involved in it to prevent false positives, but it eventually fails, and the measurement becomes junk. False alarms, and no alarms, even with the sensor disconected, or the connector shorted.

Paint over the light in the dash or remove the bulb, check your coolant level (and oil level) at every fuel stop. Keep the temperature gauge in your instrument scan, and if you see something out of the ordinary, investigate it immediately.

PS Where is the "Bell City", Pilladelphia?

BellCityDubber · « **Reply #4 on:** July 09, 2007, 02:29:47 pm »

Quote from: "saurkraut"

Sometimes these things just lose thier minds. I have a '92 Passat that just blinks randomly, regardless of tank level, or even if the sensor is hooked up or not, and even with a paper clip shorting the connector. And i will admit that it really sucks to have a red light flashing frantically while your driving, but i haven't found an elegant solution.

i put a cluster in my '79 that has a level warning light. I just painted over it since i didn't have anything to hook it up to. At night I can see a slight glimmer as it occasionally sends a frantic warning of nothing in particular.

I think VW really dropped the ball on this measurement. There must be some logic crap involved in it to prevent false positives, but it eventually fails, and the measurement becomes junk. False alarms, and no alarms, even with the sensor disconected, or the connector shorted.

Paint over the light in the dash or remove the bulb, check your coolant level (and oil level) at every fuel stop. Keep the temperature gauge in your instrument scan, and if you see something out of the ordinary, investigate it immediately.

PS Where is the "Bell City", Pilladelphia?

Well.. As an update, I added a bit more water to the tank before changing it.... and the light went away.... I wasn't "low" or down very far at all... but I haven't had the chance to take it around the one corner/bend/offramp that trips it off.

I really dont want to have to hackjob the coolant low level warning light because it's a one owner car with all maintenance records. so if it's going to get done, it's going to get done RIGHT. So no jumping pins, no shorting the bulb, or any of that.

That's what my GTI is for

I normally keep a good eye on my temp gauge anyways, but I've been toying with the idea of getting a PROPER water temp gauge over the winter.

As for my location

I live in Brantford, Ontario. Known to some as "The Bell City"

saurkraut · « **Reply #5 on:** July 09, 2007, 02:47:48 pm »

Good luck with that..

I guess i wasn't too clear in my previous post. The problem can be in the dash board, regardles of tank sensor condition, water level, and moon phase. You can have a new tank and proper coolant level, and still get the light. that means your cluster is screwed.

i wasn't advocating klugeing up your vehicle. I was trying to point out that it might not be your tank sensor that failed. It might be in your instrument cluster.

burn_your_money · « **Reply #6 on:** July 09, 2007, 02:59:03 pm »

I think VW has the low level warning because in the event of a total coolant loss the temp sensor would actually be reading the air temperature which would not accuratly tell you what temp the engine is at and could easily result in an overheating problem.

Vincent Waldon · « **Reply #7 on:** July 09, 2007, 07:22:41 pm »

The coolant sensor, at least in the rectangular bottle, is a simple design but it does seem to be a bit temperamental when it gets old.

Based on where the probes sit it should be well below the "low" level before it trips but on mine it trips when it gets even a bit below "max" and I take a corner. The circuit is a latch, meaning that once it trips, even for a split second, it will stay flashing until you shut off the car.

I find that I need to clean the sensor probes every once in a while, and I've had the wires to the sensor break twice... they seem to come into the plug at a sharp angle on my car.

Well worth making sure it works... an undetected coolant leak is sudden death to engines on the highway... don't ask me how I know... and the temperature gauge was none the wiser.

Vince

saurkraut · « **Reply #8 on:** July 10, 2007, 06:09:06 am »

Well, I think its a dandy measurement too, if it worked right. My '92 gasser has the round ball reservoir. The light started to do some random crap warnings during streight and level driving, with a full bottle.

I installed a brand new tank, the problem persisted and got more frequent. I disconected the sensor, the warnings happened in the same fashion and frequency. I jumped it with a paper clip, the warnings happened in the same fashion and frequency.

The wire is back on the tank, the reservoir is about 3/8 of an inch above MAX level, the warnings are frequent, completely random, and terminat all by themselves, with out turning off the ignition.

Since the warnings are turning themselves off without turning off the ignition switch, I'm concluding that the problem is not the tank. Its probably a cold solder joint somewhere on the back of the instrument cluster.

There is also some electrical hijinks going on in the cluster of the '93, so I suspect as VW started sourcing globally, the quality went down somewhat.

So, my point is, if you have a '92 or newer, and your coolant level thing goes berserk, it may not be the coolant level, or the coolant sensor.