flow through rads at my wits end

[r1alex]

I bought an aby avant about 2 months ago, soon after I noticed that there was very little water flow through the main radiator , thinking the thermostat us i replaced that, replaced the main rad because it had split, replaced the fan switch just incase.top hose still really hot bottom of the rad cold.Replaced the water pump cam belt and tensioner, no better, altought the plastic impeller had started to brake up, removing the thermostat has masked the problem, but this weekend I replaced the stat again with a genuine audi one just incase.Top hose is still much hotter than the bottom hose.
The expansion tank has been tested three times with a dye test for co, and has passed each time , it does not use water, and dose not overheat, running at just below 90 tonight and about one or 2 notches above befor the fan comes on statioary, anyone had this problem , about at my wits end now. I am sitting here typing this drinking, I don't drink.tech head required.

[BrianSmith_S2]

I bought an aby avant about 2 months ago, soon after I noticed that there was very little water flow through the main radiator , thinking the thermostat us i replaced that, replaced the main rad because it had split, replaced the fan switch just incase.top hose still really hot bottom of the rad cold.Replaced the water pump cam belt and tensioner, no better, altought the plastic impeller had started to brake up, removing the thermostat has masked the problem, but this weekend I replaced the stat again with a genuine audi one just incase.Top hose is still much hotter than the bottom hose.
The expansion tank has been tested three times with a dye test for co, and has passed each time , it does not use water, and dose not overheat, running at just below 90 tonight and about one or 2 notches above befor the fan comes on statioary, anyone had this problem , about at my wits end now. I am sitting here typing this drinking, I don't drink.tech head required.

sounds normal to me. on warm up the water pump draws water from the bottom of rad, and expells it through top hose. thats why on warming up the top gets hotter first.

mine also runs 2 notches below 90, then fan cuts in about 1 - 2 notches above 90. highest i c it get to is just a fraction over the 2nd notch over 90, but thats in wamr weather and heavy traffic.

Brian

[r1alex]

thanks brian

[Rusty]

Ditto, sounds normal I'm afraid. The cooling on an S2 is absolutely useless! I had a fit about it a month ago as my Rad split and thing got a little warmer than I wanted, been paranoid as hell since then!

Removing the thermostat is fine in consistent 20deg plus weather but if the engine temp goes below 80 then you go into a cold running map and start using even more fuel (yes, it is possible!). Cooler thermostats are available than the standard 87deg one so might be worth going for an 85deg? I'm sure VAG Parts of GSF can help with that one.

I have hard-wired the fan on mine and have the ultra high speed fan speed available because I have AC, not sure if it's available on normal S2s but it sure cools things down fast, even in 30+deg on a track! Worthwhile mod IMHO. Ultra high speed soes not operate normally and sounds like the car's about to take-off!

Good luck!

[Jamo]

I think it's 85-87 Andy for cold running map on the ECU. It's on s2central.net somewhere I'll try and dig it out.

[nip]

mine runs at a notch bellow 90 on a run then in traffic it rises above 90 changed......
rad
thermostat
fan switch
mtfs & after run switch
then temp sat at 90 then soon rises to 2 above 90, so changed back mfts and it sits lower temp now, i think its about nomal now constantly keepin eye on the temp gauge

[Rusty]

I think it's 85-87 Andy for cold running map on the ECU. It's on s2central.net somewhere I'll try and dig it out.

Thermostat opens at 87 and closes at 85 I think, hence those numbers.

Removing the thermostat and putting the fan on ultra-high speed dropped my temps a lot around the ring. 10deg oil and 4 deg water on a hotter day pushing harder. Worth it for a short period of time but not for daily driving.

Other thing I meant to look into was a thicker cored alloy rad but I just bought an OEM replacement instead due to time constraints. Have a spare kicking around if anyone wants it for a pattern.

[RAOUL]

[QUOTE=Rusty;232615]Ditto, sounds normal I'm afraid. The cooling on an S2 is absolutely useless! I had a fit about it a month ago as my Rad split and thing got a little warmer than I wanted, been paranoid as hell since then!

Removing the thermostat is fine in consistent 20deg plus weather but if the engine temp goes below 80 then you go into a cold running map and start using even more fuel (yes, it is possible!). Cooler thermostats are available than the standard 87deg one so might be worth going for an 85deg? I'm sure VAG Parts of GSF can help with that one.

I have hard-wired the fan on mine and have the ultra high speed fan speed available because I have AC, not sure if it's available on normal S2s but it sure cools things down fast, even in 30+deg on a track! Worthwhile mod IMHO. Ultra high speed soes not operate normally and sounds like the car's about to take-off!

Good luck![/QUOTE

I know exactly what you mean about paranoid. On my 1st & only trip to the 'Ring in 2006, my computer warned me excess heat gauge read 130°c! All the way wtih windows down, roof open and heater on full chat to keep "her" cool. Upon inspection the main cooling fan had been connected wrong way round (ring terminals, not the best idea?) by the mainstealer! So the fan was fighting the cold air being pushed into the engine bay. Swapped them over in the 'Ring carpark, HEY PRESTO! That is why i dont bother with the stealers anymore, my best mate is my trusted mechanic.

My fan comes on with ignition now, multi function temp sensor maybe? Gonna get "her" Vagcom'd today hopefully? Anyone know the part numbers/prices for the temp sensors for an ABY lump?