this is a continuation of an old topic started a few weeks ago. I have a problem with a 1989 carravelle 2.1 wasser injected.

I have replaced the temp unit on the rad and replaced the thermostat with a new on only to find the problem worse. put to old one (genuine VW oem) and it runs better. Checked all the connections. bled the system, front and rear after putting the front up on stands.

Still runs hot.

question 1. which way does the water run round the system? when the engine is idling and hot, the hoses around the engine are hot but the hose running from the back of the thermostat is still cold. One of the hoses coming from the rad is warm up the front, but the rad itself is still cold. When the thermostat opens does water push up past the thermo or suck down through it.

2. if the hoses at the join to the rad are wrong way round. will it make any difference.

3. I put both the thermostats into a pot of water and slowly brought to the boil. the VW oem opened first, while the non genuine opened later. Both opened when the water was bubbling in the bottom, just before it boiled. I feel this is a bit late.

4. Where is the temp switch that runs the gauge in the dash. I understand it is on the thermostat housing, but there are two temp senders under the housing. What is the point of them, if they have nothing to do with the circulation of the water (apart from the gauge).

5. I am running coolant in it.

6. the temp gauge is doing strange things. It goes from cold to the warning light and slowly past then sits around 3/4 and goes back down to half. Sometime goes all the way back to cold. Today went up to hot, then down to cold and stayed there. the engine was definitely not cold. Sometimes sits happily around the waring light in the middle and gives me a false sense of hope. This suggests an airlock, but I have bled it several times.

I am concerned about it as i dont want to cook the motor, as it is running really well. I need to use it for some long country drives and am just not 100% confident in it. All help gratefully received.

Mark Wilson

1. The water pump suction line is the Black metal pipe that runs under the coil. When the thermo opens the pump sucks the coolant down through it.
2.yes the must be round the right way at the front.
3.Read the numbers on the the thermostat. OE is 87-90 odd degrees.( I can supply a cooler opening unit)
4.Blue sender tells the ECU, the Black sender works the guage
5.Hope so G11
6.these things are a bitch to blead.
7. Sounds like a thermostat issue. PM me and we will sort it

Thanks Ben. I will give that and try and also put in the new thermostat with the lower opening temp, and try bleeding the system with the back up and nose down. thanks for it. If it works i will buy you a beer when i see you. mark

so when you undo the little bolt on the top of the radiator only coolant comes out and no air????

you may need to remove the radator and get it flushed is it an auto and what says the engine is hot gauge light etc

The gauge needle gets to about 1.2 way past the red light in the center of the guage. that is about 3/4 of the way across. It tends to hang around just after the little light. I did have to red light and buzzer come on during a test run and stopped strait away. not sure why, as water was there. No damage anyway.
When should the fans kick in and where would the needle be when they do.
it is an auto 3 speed. Thanks for all the help.
Mark

If the light comes on your bottle should be low on coolant.
That is an easy check.
The level should not go back up again without the addition of fluid.

To be clear - I am talking the coolant bottle in the rear LH corner - not the filler bottle behind the number plate.

My fan seems to come on when the needle tries to go past half way

Silly question, but have you checked the gauge for accuracy?
the sender in a boiling jug should be bang on 100c which is well above what the fan should turn on at.

I remember worrying that mine was running too hot when I first got it going only to find out it was just the gauge reading 8c too high.

A bad ground or dirty connections can make the gauge do silly things.
Mine jumps about 4 degrees higher when I turn my lights on.

Changed the temp sender at the back of the thermostat and a new genuine thermostat has fixed the issue. Big test is on monday when it goes down to melbourne 11/2 hours drive. Thanks for your help honeyabba.
Mark

Too easy Mark
cheers