VW T4 Forum - VW T5 Forum banner

1 - 7 of 7 Posts

·
Registered
Joined
·
2,208 Posts
Discussion Starter #1
I have this very annoying intermittent problem eighths low level red warning light coming on, the coolant is always fine and unto the max level in the bottle, I have replaced the bottle with 2 GSF ones and at present I have a genuine one on for last 10months but the light has started coming back on
If I stop and turn if engine turn back on it's fine for days hours anything really, unplug the loom plug plug back in sometimes works sometimes not
Baffling me and don't want to buy another bottle
Anyone any ideas :*T:
 

·
Registered
Joined
·
2,208 Posts
Discussion Starter #3
You can't as they are moulded into the bottle hence buying 3 so far
 

·
Registered
Joined
·
405 Posts
is there a plug from the loom which fits into the bottom of the bottle like on a golf? (not had reason to look at this on my own van yet)
The coolant light is for both low coolant level and too high temp i believe. Might be worth trying the actual temp sensor to see if the contacts are corroded or it has a dodgy earth or something

Just banding ideas about, i'm no expert!
 

·
Registered
Joined
·
2,208 Posts
Discussion Starter #5
not related to heat of the coolant as it can happen a few minutes after starting or after 15 mins driving :* 4 times on the way to work this morning
 

·
Registered
Joined
·
237 Posts
I had the same fault on a polo (wife's) it turned out to be a coolant pressure problem. There were no leaks visible but tightening all hoses solved it.
 

·
Registered
Joined
·
23 Posts
Here's the my story hope it helps you.

My T4 is a 2.0L Petrol 1993

I purchased the van 6 weeks ago and the Coolant warning light was flashing from day 1

1. I noticed the coolant was blue (not G13 which is pink)

2. Flushed the coolant out three times with water

3. Replaced the coolant with 50% G13 mix and replaced the coolant reservoir at the same time.

Coolant light still flashing :(

1. Measured the voltage at the loom connector for the coolant sensor. It measured 3vac this is correct.

2. Measured the voltage at the other sensor on the engine block that can turn on the coolant light 5vdc this is correct.

3. Measured the resistance of the of the sensor on the engine block. It's a thermistor so it's value depends on the coolant temperature. My matched the curves available on a google search. approx 2500 ohms at 20 degrees C. dropping to approx 300 ohms a 300 degrees C
http://www.autozone.com/repairguides/Volkswagen-Cars-2000-05/Coolant-Temperature-Sensor/Testing/_/P-0900c152801bfc48

4. Measured the capacitance of the coolant level sensor at approx 25uF. this is correct.

So what to do next?

Looks like it must be an instrument cluster problem but my cluster does not show any signs of the well know regulator problem.
All my guages read correctly and never miss a beat.

Here's what fixed my problem and it only took me six weeks to work out :)

1. Remove the instrument cluster there is an great guide on youtube
https://www.youtube.com/watch?v=RXM7ZreBuuY

2. The problem is the circuit that decides if the coolant light should flash or not.

3. I traced the circuit and found it is located in the combined temperature fuel gauge.

4. The fault is the push fit connectors that attach the gauge to the instrument cluster PCB.

5. Clean the connectors on the PCB and the gauge with IPA or switch cleaner.

6. Use a pair of long nose pliers to close the connectors on the pcb so they are a tighter fit on the gauge connectors.

7. Refit the gauge and test in vehicle coolant light is off.

8. When you remove the gauge you will see the flashing coolant light return.

9. Turn ignition off to reset the fault condition and refit the gauge.

10. Turn ignition on coolant light is off.

11. Disconnect the coolant level sensor and wait the coolant light will flash.

12 Turn ignition of to reset fault. Reconnect Coolant level sensor.

13. Turn ignition on. Coolant light is off Yay! :)
 
1 - 7 of 7 Posts
Top