Leaning towards blocked rad now, fault finding is sh*t at the best of times but having to remove the front of your car to carry out maintenance.....go figure!
Coolant temp problem. Thermostat?
- Thread starter BakPak
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Both heater matrix hoses are hot and so are the oil cooler hoses. The top rad hose is hot but the lower hose is cold.
How can it not be a blocked rad?
Gutted and ****** annoyed!
New water pump and rad fitted but still overheating. Took longer to overheat this time but I think it was due to a new rad being fitted.
Any thoughts guys?
New water pump and rad fitted but still overheating. Took longer to overheat this time but I think it was due to a new rad being fitted.
Any thoughts guys?
I'm surprised you haven't had a HG sniff test done? Cheap & easy way to establish if you have HG failure.
Ok when it's hot, 115 -120 degrees the extra fan is on and coolant is dripping from the overflow on the expansion bottle and the top rad hose is hot but not hard! I would expect the coolant system to pressure up if the head gasket had gone.
However the heater goes cold when these shenanigans are going on.
What does an average head gasket replacement cost lol?
However the heater goes cold when these shenanigans are going on.
What does an average head gasket replacement cost lol?
Yep probably should of been one of the first on the list.
Have you flushed the heater matrix out as K seal, Rad weld etc just love blocking that up. I would only ever stick products like that in as an emergency get me home solution, & then flush it out quick.
If it does show up CO2 in the coolant you may still have a get out of jail card.
I had very similar problems to you with my A4 a couple of years ago & read on a forum somewhere that there were known problems with some PD engines not having correctly torqued up head bolts from the factory. I got my mechanic to check them & sure enough 2 of my cylinder head bolts were under torqued.
That was about 30,000 miles ago & I've never had a problem since.
Have you flushed the heater matrix out as K seal, Rad weld etc just love blocking that up. I would only ever stick products like that in as an emergency get me home solution, & then flush it out quick.
If it does show up CO2 in the coolant you may still have a get out of jail card.
I had very similar problems to you with my A4 a couple of years ago & read on a forum somewhere that there were known problems with some PD engines not having correctly torqued up head bolts from the factory. I got my mechanic to check them & sure enough 2 of my cylinder head bolts were under torqued.
That was about 30,000 miles ago & I've never had a problem since.
Why are you wasting your money on things it's not I told you right from the start it was your head gasket .. You could of had it all fixed by now chances are now you've cracked your head and will need a new one now
When I first drove the car after new rad etc I thought it was sorted. It took 10 miles of hard driving to overheat and after a mile of gentle driving the temp returned to normal. I then drove the car hard again but could not get the system to overheat again.
Happy days ish!
Had the sniff test carried out this morning at a different garage and it's negative. I even took it for 20 minute thrash and tested again, still negative.
This mechanic felt the bottom hose was too cool so I checked the old genuine thermostat in the kettle and it definitely opens so I'll fit it later today.
This whole problem is pointing towards poor circulation or the stat is sticking??
Sorry to disappoint you vr6gordy but it's not the HG dude.
Had the sniff test carried out this morning at a different garage and it's negative. I even took it for 20 minute thrash and tested again, still negative.
This mechanic felt the bottom hose was too cool so I checked the old genuine thermostat in the kettle and it definitely opens so I'll fit it later today.
This whole problem is pointing towards poor circulation or the stat is sticking??
Sorry to disappoint you vr6gordy but it's not the HG dude.
Ok, I removed the thermostat a couple of days ago and naturally it runs cooler, 60-70 degrees. If I thrash the car it will reach 90 degrees.
Has anyone ever encountered a blocked coolant channel in the system.
Bear in mind I have had fitted a new radiator, water pump and thermostat?
Has anyone ever encountered a blocked coolant channel in the system.
Bear in mind I have had fitted a new radiator, water pump and thermostat?
No dude. Try and keep an open mind, it's too easy to focus on something obvious like head gasket.
Ordered a new genuine thermostat from Darkside and even though the temp reaches 90 the bottom hose remains cold. I'm only driving 10 miles to work so a hard drive tomorrow will properly check it.
Just a question, does it matter how the thermostat is orientated when fitted?
Just a question, does it matter how the thermostat is orientated when fitted?
I recently fitted a genuine stat. There are wee plastic clips, which I may add I never noticed were there, that were to keep the orientation correct or something, but I now believe is old tech as orientation doesn't matter anymore I believe? I stand to be corrected though.
Anyways, I fitted mine, and as the common problem goes the wee plastic clips snapped and blocked my stat. Took it out and removed the broken clips and all works fine now!
I just replaced my stat the same way as the old one came out.
Can't see how a compression test will help?
The engine runs smooth and boosts well. The thermostat just will not open! I removed the stat again this morning to avoid it overheating.
I'm getting close to the gallon of petrol and a match situation!
On the bright side I managed to blag a new battery from Halfords today foc.
Clutching at straws now but is there anything in the CTS housing that could fracture and cause a blockage?
It's as though hot coolant isn't reaching the thermostat. Why won't it open when the temp gauge reads 110 and all the hoses are red hot apart from lower hose which is cold?
Please don't suggest HG lol!
It's as though hot coolant isn't reaching the thermostat. Why won't it open when the temp gauge reads 110 and all the hoses are red hot apart from lower hose which is cold?
Please don't suggest HG lol!
I thought the sniff test would have eliminated a cracked head. The engine was running very hot when it was tested for the second time. Negative.
Even if the head was cracked and or the HG was gone, why wouldn't the thermostat open?
Even if the head was cracked and or the HG was gone, why wouldn't the thermostat open?
You got me thinking dude! Not just a flexible hose but the metal pipe linking the heater matrix outlet to the block via the oil cooler. Thanks.
After flushing all the hoses again I reassembled and gave it a run. Same situation with the thermostat refusing to open even though the metal pipe from the heater matrix via the oil cooler is hot to touch.
I'm a stubborn b*stard at times and this is definitely not going to beat me! Even if I cannot fix it I want to know the cause for future reference.
I'm a stubborn b*stard at times and this is definitely not going to beat me! Even if I cannot fix it I want to know the cause for future reference.
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My mate had exactly this on his 2003 PD130 A6.
Was fine if he drove gently. Give it beans and it would boil over and spew the coolant everywhere.
Went thru everything you've done, until i eventually convinced him to change the head gasket. Did that and it sorted it.
Probably worth changing the timing belt and water pump while its apart too.
Was fine if he drove gently. Give it beans and it would boil over and spew the coolant everywhere.
Went thru everything you've done, until i eventually convinced him to change the head gasket. Did that and it sorted it.
Probably worth changing the timing belt and water pump while its apart too.
Can you remember if his thermostat was opening? You're probably right mate but if it is getting that hot why won't it open and circulate like it does with the thermostat removed?
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Yeh his stat was opening fine, infact it was potentially the stat that kicked off a whole sequence of parts. The original stat was opening too early, and the car was never getting to 90c. One day he was driving it particularly hard and it boiled over. I suggested the stat might be stuck a tiny bit open, meaning it would run cool normally and then boiled over because that stat didnt open fully. He replaced the stat with new and that made it come up to 90c nice and quickly, but it would then boil over almost every time he took it out. Initially he blamed the stat like you, then went on to blaming the radiator and water pump which he paid to have replaced. Infact it was simply that with the engine now running at 90c, there was much less headroom for the temperature to rise when it was overheating.
IMO, The missing stat is just masking the issue, by giving more headroom before the pressure and temperature gets too high.
IMO, The missing stat is just masking the issue, by giving more headroom before the pressure and temperature gets too high.
But my stat will not open even if it is boiling. Basically with a stat fitted the bottom rad hose is now cold whatever happens temp wise.
When I had the sniff test carried out (twice) the bottom hose was obviously cold, therefore no circulation so could that affect the results of a sniff test?
Would the pressure increase in the system stop the stat from opening?
It just doesn't make sense!
Everything is worth considering mate I think. It looks a pig to get to though.
How difficult is it to remove the housing?
It will only be warped if it's had some serious heat. 110-115 will not be enough to warp it.
Not necessarily.
If it's not over heated and there's no sign of corrosion. I wouldn't bother.
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