Audi s2 Aby running hot 95 degrees or so

[Chris5044]

Hey everyone! its been a long time!
I hope you are all well and healthy!

My s2 aby seems to be running 95 degrees or so.
I have recently removed the aux radiator mod and bypass.

Could it be this? or a blocked radiator? or worth upgrading the radiator to a larger alloy one?

What wisdom would you know about something like this?

Huge thank you in advance.

[andyg plym]

Had this very recently and it turned out to be the mfts switch on the water rail reading 10 degrees out which when I read up is not uncommon. Refitted the original and all ok. They are a nightmare to bleed too...

[Henkjan]

following this, I observed the same after deletion of my aux rad. did not rise any further, but then did not really push it hard then

[Chris5044]

Had this very recently and it turned out to be the mfts switch on the water rail reading 10 degrees out which when I read up is not uncommon. Refitted the original and all ok. They are a nightmare to bleed too...

hey thank you! did you order a new one and replace this? can i find this thing online? I have no idea what that thing is. thank you!!

[andyg plym]

I think it more likely you need to bleed the system. Did you just remove the rad and join the pipes? I’d suggest a full flush through the engine and radiator - lots of guides on here then reconnect, refill and thoroughly bleed the system. I’d say more s2’s on the roads nowadays don’t run the aux rad so should be fine

[SteveH]

Aux rad removal shouldn't raise your temps unless you live in a very hot country. More likely to need bleeding, dodgy thermostat or MFTS.

[Fat Audi 80]

my new MFTS reads hot. The engine is fine, the sensor is too sensitive!

[DeS]

Most important is if the fan switch works properly.

[newsh]

I have recently removed the aux radiator mod and bypass.

.

I’m not sure what this means. You’ve removed the Aux Rad?
What’s the mod and bypass??

The word “bypass” suggests you’ve joined the Aux rad pipes together. This would allow an easy route for the water to avoid the main rad, or indeed for the water to circulate down through the rad and up through the bypass, avoiding the engine.

The jury is out on this but definitely ..
When you remove the Aux Rad you must plug the two pipes.

Also if you’ve fitted a new MFTS (or it’s starting to go bad) it may read high, lots of them do, best way to check coolant temp is to do it in Vagcom Measuring Groups as the ECU takes it’s temperature feed from the white sensor on the back of the head.

[newsh]

I see in your other thread, you got this info about hot running from the tuner so he was probably looking at the output from the head sensor in the Emerald software.

[martinjs]

What was it running like before you removed the aux rad?

[martinjs]

Mine started running hot last summer, the main rad was partially blocked.

[Chris5044]

I think it more likely you need to bleed the system. Did you just remove the rad and join the pipes? I’d suggest a full flush through the engine and radiator - lots of guides on here then reconnect, refill and thoroughly bleed the system. I’d say more s2’s on the roads nowadays don’t run the aux rad so should be fine

Huge thank you bro!
Yes I bled the system, Ill revisit the car and bleed it, it just failed the MOT so trying to sort this out now.

[Chris5044]

I see in your other thread, you got this info about hot running from the tuner so he was probably looking at the output from the head sensor in the Emerald software.

I think from the guage, it does read 95 on the temp guage

[Chris5044]

Most important is if the fan switch works properly.

I know the fan works, but I have heard about the 2 stage fan?? Can someone perhaps tell me more on how this works? Ive only noticed the fan come on or off..