Cooling Problems

g-lobo

Member
Had classic thermostat issue of taking ages to warm up. Occasionally in traffic gauge would dip below 90.
Changed for ECP type (odd: gasket around the thermostat perimeter). Lost quite a lot of fluid and ran car with reservoir top off to bleed system.
Now warms up quicker and heater useful much earlier. BUT: only holds 90 if heater not engaged. If heater on dips well below, even at speed.
Anyone offer advice?
Many thanks.
 
Had classic thermostat issue of taking ages to warm up. Occasionally in traffic gauge would dip below 90.
Changed for ECP type (odd: gasket around the thermostat perimeter). Lost quite a lot of fluid and ran car with reservoir top off to bleed system.
Now warms up quicker and heater useful much earlier. BUT: only holds 90 if heater not engaged. If heater on dips well below, even at speed.
Anyone offer advice?
Many thanks.
Is it the temperature gauge which dips, or do you feel the temperature drop in the heater output?
Check that the fan is not running continuously, possible FCM fault.
Mac.
 
Seal sound be same as original ecp do them for 50p and I had a circoil stat that came with car worked great until a piece of plastic debris jammed it open so not the stats fault at all
 
It's interesting, mine does the opposite, it's goes between 80-90C after 15 minutes, but only stays solid on 90C when the car is stationary.
 
I had this issue, replaced both my thermostat and temp sensor with genuine audi ones and fixed my issue, car warms up to 90 in 5 min. Is a tdi 90
I've already changed the temp sensor a few times, only found aftermarket ones though, the 3rd one at least has reached 90° at some point. Where did you get genuine temp sensor and thermostat from? Cheers
 
I had this issue, replaced both my thermostat and temp sensor with genuine audi ones and fixed my issue, car warms up to 90 in 5 min. Is a tdi 90
Thanks @Charles You may have just explained why having changed my thermostat, it only goes up to 90 in traffic.
 
Thanks @Charles You may have just explained why having changed my thermostat, it only goes up to 90 in traffic.
My thoughts where if the thermostat opens early unless stationary the radiator will be getting enough air over it to keep the coolant below 90, then be able to reach 90 when stationary as no air moving over it. I've also never seen my cooling fan spin unless my air con has been on min so this doesn't effect it really.
 
I've already changed the temp sensor a few times, only found aftermarket ones though, the 3rd one at least has reached 90° at some point. Where did you get genuine temp sensor and thermostat from? Cheers
I made sure to replace both together as a dodgy thermostat will stop the coolant from reaching 90, and a dodgy thermostat won't read 90. I got mine from my local audi dealer who are very friendly, especially the parts department! Don't bother with the o ring unless it hadn't been changed before! Here's my invoice with parts number, but they should just check against your reg!
20230101_205750.jpg
 
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I made sure to replace both together as a dodgy thermostat will stop the coolant from reaching 90, and a dodgy thermostat won't read 90. I got mine from my local audi dealer who are very friendly, especially the parts department! Don't bother with the o ring unless it hadn't been changed before! Here's my invoice with parts number, but they should just check against your reg!View attachment 102777
That's great, thanks Charles.
 
Had classic thermostat issue of taking ages to warm up. Occasionally in traffic gauge would dip below 90.
Changed for ECP type (odd: gasket around the thermostat perimeter). Lost quite a lot of fluid and ran car with reservoir top off to bleed system.
Now warms up quicker and heater useful much earlier. BUT: only holds 90 if heater not engaged. If heater on dips well below, even at speed.
Anyone offer advice?
Many thanks.
Still trying to solve this. Thanks to those who have replied.
Questions:
How important is it to engage the thermostat in the “fingers” in the thermostat housing? I only have one left.
How do you do this? Clip into the housing and then attach to block?
Is this achievable with the quick method (detailed in the forum) of not moving any other components?
Many thanks
 
Still trying to solve this. Thanks to those who have replied.
Questions:
How important is it to engage the thermostat in the “fingers” in the thermostat housing? I only have one left.
How do you do this? Clip into the housing and then attach to block?
Is this achievable with the quick method (detailed in the forum) of not moving any other components?
Many thanks
If the fingers are missing it is easier to put the thermostat into the block followed by the O-ring, then tighten down the thermostat housing in place. It is only if the fingers are present that it is possible to lock the o-ring and stat into the housing before mounting it in one go.

If you're quick and reasonably dextrous (and sit the new thermostat on top of the alternator), it is possible to get the old o-ring and thermostat out and the new one in place (preventing significant coolant loss) in the space of a couple of seconds by using both hands. Then while holding the new thermostat in place you can insert the o-ring, and then the housing. The worst bit is getting the lower housing bolt located and tightened up without dropping it.
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Without removing other components .. assuming the fingers are gone the housing can be left attached to the coolant pipe coming from the radiator and will simply pull off once unbolted, and the alternator can stay put, but you will need to remove the engine acoustic cover and the boost return pipe (if a tdi) as without doing so there simply isn't any means to access the thermostat location. Secondly you will need tools that can access the lower bolt (combination of being narrow enough and stepped / angled in such a way that it gets around the housing with sufficient clearance from the alternator casing to be able to turn the bolt).
 
If the fingers are missing it is easier to put the thermostat into the block followed by the O-ring, then tighten down the thermostat housing in place. It is only if the fingers are present that it is possible to lock the o-ring and stat into the housing before mounting it in one go.

If you're quick and reasonably dextrous (and sit the new thermostat on top of the alternator), it is possible to get the old o-ring and thermostat out and the new one in place (preventing significant coolant loss) in the space of a couple of seconds by using both hands. Then while holding the new thermostat in place you can insert the o-ring, and then the housing. The worst bit is getting the lower housing bolt located and tightened up without dropping it.
|
Without removing other components .. assuming the fingers are gone the housing can be left attached to the coolant pipe coming from the radiator and will simply pull off once unbolted, and the alternator can stay put, but you will need to remove the engine acoustic cover and the boost return pipe (if a tdi) as without doing so there simply isn't any means to access the thermostat location. Secondly you will need tools that can access the lower bolt (combination of being narrow enough and stepped / angled in such a way that it gets around the housing with sufficient clearance from the alternator casing to be able to turn the bolt).
Thanks for this detailed reply. I am now one of the no-fingered and have become quire accomplished at removing and reinstalling with ratchet spanners, stubby sockets and (new technique) a 5mm hex drive. However, I am still having problems seating the gasket correctly. Each time I try it seems to slip out of place slightly, resulting in a faulty seal. Inspection of the new gaskets I have removed clearly show this, and also that one side is very flattened. Perhaps a sign of over tightening? Does anyone have any tips to sort this? New gasket in hand.
Many thanks.
 
Thanks for this detailed reply. I am now one of the no-fingered and have become quire accomplished at removing and reinstalling with ratchet spanners, stubby sockets and (new technique) a 5mm hex drive. However, I am still having problems seating the gasket correctly. Each time I try it seems to slip out of place slightly, resulting in a faulty seal. Inspection of the new gaskets I have removed clearly show this, and also that one side is very flattened. Perhaps a sign of over tightening? Does anyone have any tips to sort this? New gasket in hand.
Many thanks.
Hello,

which thermostat did you buy? Just in case the o-ring is different to the ones most commonly used.

If I remember from the occasions I've replaced the thermostat, this is pushed into place and then held with one finger, then the o-ring is positioned so that it sits on the front face of the thermostat, nestled into the engine block - obviously it is necessary to walk the fingers holding the thermostat over this as the o-ring is inserted. Then the housing is screwed in place on top. What you are describing sounds as if the o-ring is too large so it isn't actually seating into the hole where the thermostat has gone, and is being crimped by the housing hence the leak. Is this the correct interpretation or do you have a better one? I take it there isn't an o-ring behind the thermostat in the block before this is inserted?

Are you able to take a photo of the thermostat and o-ring in situ to highlight the issue?

best of luck!
 
Thanks for this detailed reply. I am now one of the no-fingered and have become quire accomplished at removing and reinstalling with ratchet spanners, stubby sockets and (new technique) a 5mm hex drive. However, I am still having problems seating the gasket correctly. Each time I try it seems to slip out of place slightly, resulting in a faulty seal. Inspection of the new gaskets I have removed clearly show this, and also that one side is very flattened. Perhaps a sign of over tightening? Does anyone have any tips to sort this? New gasket in hand.
Many thanks.c

Check the part number against my invoice if its a tdi
 
Hello,

which thermostat did you buy? Just in case the o-ring is different to the ones most commonly used.

If I remember from the occasions I've replaced the thermostat, this is pushed into place and then held with one finger, then the o-ring is positioned so that it sits on the front face of the thermostat, nestled into the engine block - obviously it is necessary to walk the fingers holding the thermostat over this as the o-ring is inserted. Then the housing is screwed in place on top. What you are describing sounds as if the o-ring is too large so it isn't actually seating into the hole where the thermostat has gone, and is being crimped by the housing hence the leak. Is this the correct interpretation or do you have a better one? I take it there isn't an o-ring behind the thermostat in the block before this is inserted?

Are you able to take a photo of the thermostat and o-ring in situ to highlight the issue?

best of luck!
Still having problems with this apparently straightforward job.
Originally fitted a Circoli stat that has a formed gasket that sits around its perimeter. Advised here to also fit the conventional O ring seal on top of this. This is very difficult as the seal sits proud of the face and has nowhere to go when compressed. As a result it deforms and sometimes seals, sometimes not.
Anyone got thoughts on this?
Tried replacing with a febi stat and non-febi O ring from ECP. Goes on easily but leaks. Perhaps this needs a dedicated gasket?
All thoughts welcome.
Many thanks
Colin.
 
Still having problems with this apparently straightforward job.
Originally fitted a Circoli stat that has a formed gasket that sits around its perimeter. Advised here to also fit the conventional O ring seal on top of this. This is very difficult as the seal sits proud of the face and has nowhere to go when compressed. As a result it deforms and sometimes seals, sometimes not.
Anyone got thoughts on this?
Tried replacing with a febi stat and non-febi O ring from ECP. Goes on easily but leaks. Perhaps this needs a dedicated gasket?
All thoughts welcome.
Many thanks
Colin.
this is giving my 6th sense all sorts of bad feelings. Do you have a part number for the Circoli you are fitting?

The way I read the above is that the Circoli thermostat you are using already has a gasket on the outward-facing edges of the pressed flange that runs around the periphery of the thermostat, which in turn suggests that this is too thick and will force everything outboard of this to be crushed by the housing or cause a leak.

I've fitted (and replaced) 2 Circoli thermostats - and more recently replaced one of them with a Febi. All had a simple pressed metal outer ring, with a pressed metal hoop projecting outwards that goes over the top of the thermostat gubbins in the middle. They all fitted first time pretty well and did not leak in any instance. I should point out that I learnt how to do this from A2oc forum tutorials so it is not as if you are being lectured by a lifelong mechanic - ie - I am completely unskilled at this.

When pushed home, the metal ring of the thermostat sits maybe a couple of mm recessed into the engine block. Then the thick o-ring goes in afterwards and sits in the remaining aperture by friction until the housing is fitted over the top and screwed home.

If we can eliminate the wrong thermostat being used, is there anything stuck in the block (ie, another o-ring?) that is making your thermostat / o-ring combination stand proud of where they are supposed to be?

If I've not completely misread your post above, can you send a photo of the thermostat in case it is obviously wrong?

I'm sure this will be easily resolved, very best of luck!
 
I’m guessing you have something like this and are fitting a second o-ring?https://www.eurocarparts.com/search...1Nw3BUz1M4hJ3ECAGwmrIe1BcF0r-kwkaAvPdEALw_wcB
Exactly. A second O ring doesn’t make sense so I have just refitted (very quick process now!) without it. Gives enough resistance to tighten down on and doesn’t appear to leak. On inspection the febi stat ( now removed) might well need a thicker gasket than that supplied by ECP. I’ve ordered one to find out and have a spare
 
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