S2 ABY Over heating at idle

[larsaskogstad]

If it's hot and it seems normal I would
- Do a pressure test and see if it's sealed properly. + get a new coolant reservoir cap.

- Measure the radiator with a good IR thermo on the main rad and see if you have approx the same temperature on it on top,mid,bottom or if it's massive differences. If so, change it. Refill correct coolant for your system.

[B5NUT]

That hose gets hot, and I'm getting good flow from the Aux rad. The main rad on the other hand is poor, if I block all the ports up except one at the top and bottom, put a hose pipe at the bottom I get water coming out of the top but it's not what you call gushing.

I've just ordered a new radiator this morning, removed the bottom rubber bush easy enough, but the side one is stuck fast.

[B5NUT]

If it's hot and it seems normal I would
- Do a pressure test and see if it's sealed properly. + get a new coolant reservoir cap.

- Measure the radiator with a good IR thermo on the main rad and see if you have approx the same temperature on it on top,mid,bottom or if it's massive differences. If so, change it. Refill correct coolant for your system.

What I was seeing with the temps was the top getting hot and the bottom starting to get hot but the middle of the rad was cool, and took a while to get hot all the way through. The Aux rad on the other hand had a far more even heat when checking with the IR thermometer. I should have just change the main rad when I found the expansion tank was full of brown crud, and it's not easy to flush out, it's almost like a paste when you get chunks of it coming out and you squeeze it between your finger

I'm also 100% sure it's not any airlock, the systems been emptied 4 times now and I've refilled it as per the recommend steps written on the forum. The current coolant pump has only done about 4K miles but it's over 10 year old looking at the servicing history I have for the car. I have a new pump to fit when I do the cambelt.

[Ian Simmonds]

I know it’s a different model of car but it might just give you a pointer as to what is going on with yours

My Ur Quattro running normally and not overheating….

All taken from front with fan cutting in and out.

T = tank
F = fins

Main rad.
Top to bottom - L to R
T87.5. T87.5. T84.7
F73.6. F74.0. F77.1
T50.3. T47.5. T46.2

Aux rad.
L to R
T75.3. T88.0

D’OD’s car with overheating issues.

My results are as follows, car had a good run and also sat in lots of traffic so properly warmed through.

All results left to right as simmos.

Tank l 92 mid 90 r 84
Mid rad L 58 mid 79 r 64
Bottom L 31 mid 26 r 24
Aux rad. L 75 mid 66 r 58

[larsaskogstad]

Would change out the rad, it probably doesnt hurt anyway. Did you say that both heater matrix hoses was hot? Sorry if I missed it.
Btw. when I filled the system I had to manually fill hose from top of rad to engine. First then I got it bled properly. (Followed guide on forum as well).

[B5NUT]

So the new radiator arrived today. It's a little bit thinner that the OEM one by about 7mm, which has caused an issue with the top right mounting being to short, so I'm going to have to make up a spacer as it's now about 7mm to short. However the new radiator has now fixed my cooling issue the car is bang on 90 and and the fan has now kicked in twice while I tested it at idle for around 10-20 seconds, and the aux rad is no longer taking the brunt of the cooling.

Thanks for everyone help with this it's much appreciated.

The only issue I have now is the aircon switch inside the car still does not switch on the the very low speed fan, so I'm going to have to fix that one before the aircon system is regassed, however I'm sure the pump will be knackered anyway Is the aircon low speed fan controlled by the blue resistor pack located somewhere at the front of the car?

[steve briance]

Great news! Sludge or an internal break down in the old rad?

[newsh]

Yes I believe the resistor pack does the slow speed. If you can read current track diagrams they’re on S2 Central, I’d link to the right one for you but it’s a copy of an old html website in Frames and links don’t work.

https://Www.S2Central.com

[B5NUT]

Great news! Sludge or an internal break down in the old rad?

Think it was more sludge. From what I could see the internals looked to be OK, just lot of nasty brown sludge.