S3 heater problems after new stat and coolant - alternating hot then cold...

[Omniquito]

Hi guys,

Fitted a new oil pump and gauze and replaced the stat and coolant whilst I was there as car wasn't getting up to temp and all is fine and dandy BUT I have noticed that no matter what temp inset the car to the fans blow warm then cold constantly alternating resulting in a really hot cabin eventually!

The system appeared to bleed fully and have a stable coolant level for 3 weeks now...

Any ideas what it could be please guys? It was working 100% ok before I did all the work...

Thanks, Neil.

 

[Omniquito]

Can't believe nobodies seen this problem

 

[Westy]

Once the car is up to temp, pop the bonnet and grab the lower and upper red hoses and see if either of them are cold. Also check the 2 heater matrix hoses by the bulkhead as air does like gettin stuck in there.

If any of the hoses are cold you'll need to remove the header tank lid and start squeezing the hoses to try and get any air out. Also try revving the car in neutral with the header tank lid off as this will spin up the water pump and helps force any air out.

I'm sure it must just be a little bit of air somewhere in the system.

 

[hades-]

was it OEM stat ?

 

[Omniquito]

Hi Westy, thank you i will try that tomorrow. I must admit that i guess no news is usually good news in the fact that it will most likely be trivial
It was an OEM stat too, heard too much bad press on non OEM ones...

 

[MILF]

Just thought I'd add that today I had the lovely opportunity lol of changing the stat on my AMK S3. It was a aftermarket parkers part and ALL I CAN SAY IS WOWWWWWWWW!!!!

I am so happy with the heat now it is unbelievable!! it actually sits at 90 and doesn't move whether the heaters are on full or you're on the motorway! Great result I must say.

--Reason why I changed it today because I had travelled from Leicester to London and back today and during the whole journey, my temperature gauge sat at 60oC and only moved a little when the motorway came to a hault due to congestion. All I can say I simply cannot express what a difference it has made and the heat is phenomenal!

--Bleeding advice--

Turn heaters on..set to full..rev to approx 3k with coolant cap off and wait till it starts spitting coolant out the header(my method) lol