Radiator Expansion Tank / Coolant Level Sensor...

[bacardincoke 42 1 Cars]

Mentioned elsewhere that I've the bulkier radiator / twin fans from a TD fitted to my '89 1.9 GTI.

 

I've the expansion tank off at the moment and will likely be replacing it due to heavy corrosion around the metal inserts of the various inlets.

 

This is an internet image of what my existing tank looks like...

 

 

Is this the original type of tank for a 1989 GTI, or if there is a difference, was it too changed to a TD item at whatever time the radiator was exchanged?

 

 

 

 

As a side issue and because there's a couple of good write ups on the forum about the coolant level sensor (and the problems they can have) I took mine out and sure enough it was completely clogged up and wouldn't have been able to show a low reading .

 

The white circular float with the ring magnet in the images below was stuck half way up the central rod you see in the brown housing, it needs to be able to rise and fall with the coolant level to activate / deactivate the warning light.

 

Didn't take much to clean it all up and it now slides up and down freely, which I thought would be the fix.

 

Unfortunately the sensor still didn't work so took the top off and pulled out the gubbins you see with the pink blob on the end.

 

The photo was taken after I re-soldered the thin wire to the metal part holding the glass reed switch. It had corroded and parted company... the blob is resin I added after to make it stronger / watertight.

 

The cavity it sat in was full of a marzipan like material, presumably some sort of waterproofing, but it'd obviously not done its job.

 

After the insides were out I filled the empty cavity with acetate thinners, couple of washes cleared dissolved and washed out the old filler.

 

I used white grease to pack it when refitting, works perfectly now.

 

No doubt someone will show me where to get new sensors for a couple of quid, but apart from the satisfaction of doing it myself, I could only find one on-line and for over £90!

 

Hopefully save someone else having to fork out for a new sensor too.

 

 

 

 

 

 

 

[Ozymandis 97]

Nice repair, have done similar myself. its so crude an arrangement its great.

All the TD 205 I have, or had, have the "square" black header tank (which i think of as a GTI) and all the NA diesels have that "round"  type.

[Tom Fenton 1,541]

Header tanks changed at phase 2, on the GTI’s. Phase 1/1.5 had the white spherical tank. Phase 2 the black square tank.

Arguably the spherical is the better tank, I’ve never had a problem with one, whereas the squared off tanks seem prone to splitting.

[jackherer 543]

As Tom says that is the right tank for an '89 GTI. The sensors in the later black tanks work in a different way electrically so you can't just swap them over without altering the wiring loom to suit.

[bacardincoke 42 1 Cars]

Thanks all... I found a 1989 date mark and part number when the grime was cleared off so appears to be the original tank.

 

When I was looking for a replacement no two sellers gave the same answer as to what tank was suitable. What made me question if it was a replacement (even one from long ago) was on the whole any I found that appeared to be the same style / part number, came back as only suitable for diesels.

 

Tempting fate but one's on it's way now.

 

This is the old tank... all the inner metal collars are completely rusted, one of them was so furred up it can't have been letting much water in or out. Would probably also account for mass of particles and muck in the float chamber

 

Seems odd Peugeot would go to the trouble of creating a complicated level sensor that uses a magnet to avoid corrosion, yet similarly exposed ordinary steel elsewhere.

 

In another post it was mentioned that Lotus used Peugeot switch gear... found a few references to the Peugeot level sensor being used in the Esprit (and with the same problems), might explain the high price being asked for the new one I saw.

 

 

[jackherer 543]

6 minutes ago, bacardincoke said:

Seems odd Peugeot would go to the trouble of creating a complicated level sensor that uses a magnet to avoid corrosion, yet similarly exposed ordinary steel elsewhere.

They only cared about parts lasting for the warranty period, maybe a bit longer but certainly less than ten years and they made it that far easily. If anything they are over engineered, my 2001 BMW E39 expansion tank dissolved into slush when it was less than 15 years old.

[DamirGTI 342]

... not to mention quite a few new cars which do not even have coolant level sensor feature , and some of those lacks the coolant temp. gauge on the instrument clusters ! (despite it being "hidden menu option" , but still notoriously stupid/crooked for the car owner but good for the OE service chains)

 

 

D

[bacardincoke 42 1 Cars]

Probably going to sound obvious to most, but in case like me you're still learning the basics and you want to check if your sensor's clogged up, or if not is still working...

 

Without checking you'll be unaware there's a problem as the dash light doesn't illuminate even if the level's low... or I suppose potentially it could also happen the other way about and the warning light is on continuously if the float is stuck over the reed switch, even the level's correct.

 

I tested the sensor off the car by wiring it up to a 12v battery with a bulb in the loop, then raising it up and down in a bowl of water. You'll see the water freely drain or plenty of bubbles as it enters the chamber through the 2 x holes on the side and one in the base.

 

To check the warning bulb / car wiring, connect the sensor back into the car and turn it upside down, the right way up while out of the header tank. You should clearly hear the float slide up and down, but it'll also activate / deactivate the dash light depending on position.  

[alanx 1]

My 93 CTI 1.9 has the same white spherical tank while the 92 GTI 1.9 has the black square one.

[SRDT 175]

On the 309 it's the same round tank but not the same sensor:

 

It works with a "water level box" that will light up the warning light if there is a problem with the sensor or it's wiring.

 

It's the same kind of sensor on the square tank but the electronic is inside.