b6,1.8t AVJ,5 SPEED MANUAL COOLANT/HEATER ISSUE

[fourringsrus]

Hi all, just picked up the above y reg January '01 b6 1.8 turbo 150.
The car is generally is cracking order with just a couple of tiny scratches etc which should vanish when properly polished and waxed.
The only niggle is that the temp gauge is only getting to around 65/70 and the heater is blowing cold.
When I collected the car 1 week ago the seller showed me bills etc for cam belt/water pump at around 25,000 miles and 2 years ago, so I felt that they are not imminent jobs.
He went on to explain that since he was given a newer car the Audi was parked for a couple of months and when he started it before Christmas the temp gauge was not rising to 90 at normal running temperature.
He was advised that he had a coolant temp sensor playing up so replaced it to no improvement, so went on to change the thermostat (£60 part)

This morning after a week of use and being bloody cold each day I decided to have a bit of a look about, so having read a few similar threads here on the forum this is the score so far;
Started car from cold and with coolant level checked and good
Allowed car to sit and idle for about 20 minutes
Altered heater controls in all positions, up/down, max cold to max hot etc and all flaps seem to be moving air about correctly
Gauge still at 70

Under bonnet
Top rad hose hot
Water pipes coming from what I think is the oil filter housing, hot
Bottom rad hose cold
Cant see hoses going to heater matrix, so don't know what they are doing.
Got the hump and thought I might nip up the village to my mates garage and see if he was able to shed any light on things or check anything for me.
Garage was closed, so turned around but noticed temp gauge climbing for the first time and assumed that there had been an air lock which I had cleared while squeezing hoses etc.
Got back onto my driveway and sat playing with the heater controls waiting for a sudden burst of heat to confirm my success.
The gauge started to drop back down to 70 and the air still cold.
Revved the engine to around 2.5/3000 rpm and heat started to come through the vents but turned cold immediately that I came off the throttle

Am I to think that the water pump is dud and just spinning on its shaft, and possibly replaced with a cheapo at the last occasion, or that the thermostat is a cheapo e-bay jobby, and that all he told is lies
I am thinking that I should ignore everything he said and start afresh from the beginning but I can't just throw money about pointlessly

Who has had this issue and what was the actual cure

January 2001
Audi A4 B6 1.8 TURBO 150 AVJ engine code , 5 speed manual with 91,000 miles
The car drives and runs superbly, if a little slow at starting from cold.
Many thanks in anticipation

Stuart

[kite]

It sounds like a failed stat to me.

I wish I could tpye...

[fourringsrus]

Yes it does but he said it was new, does £60 just for the part sound right, he said the stat comes in its' own housing.

Just being reading on Audizine, would a clogged matrix/core cause the temp gauge to play like this

[kite]

I think a failed waterpump would cause overheating.

I wish I could tpye...

[fourringsrus]

Yep, agreed and I think the stat does work and that I must a flow restriction. Reading some of Crashers' replies to similar threads the matrix clogging is common on this model so I'll have another look in the morning as I now know the location of the pipes is not where I had been looking and that they are a doddle to access
Thank you friend
Stuart

[fourringsrus]

Flushed my heater core with CLR. Lots of pics.

can anyone confirm which of the two pipes is the "in" and which is the "out", reading the link above with pictures I assume that the bottom hose is the "in" and the top is "out", can anyone confirm this ?

Thanks

Stuart

[fourringsrus]

Well, didn't get the matrix sorted or cleaned out yet but as there was not any water at the pipes anyway, I'm going for the thermostat and ignoring what the fibbing sod told me.
As I'm lead to understand that this engines' stat and apparently many others these days, comes in its' own housing would anybody on here have access to a diagram or picture of what this thing looks like and where it's positioned and whether I'll need any special tools or tricks to change it.
Obviously drain fluid swap unit refill fluid , but are there any little tricks to bleeding the system, ie; cold engine, hot engine, car upside down and back to front,.you get the picture.
Any pictures and tips gratefully received, and does £60 sound right, alternatively could it be just the old fashioned £10 thermostat like most old cars?

1.8 turbo AVJ, 5 speed manual in a B6, January 2001

Many thanks

Stuart

[Doctle Odd]

a4 b6 thermostat | eBay

[fourringsrus]

Thanks Doc, didn't see my one there, but they all look like normal stats , as opposed to what I expected

[Doctle Odd]

If you search with your engine size there should be plenty, genuine is always best! cheap easy fix tho