Strange overheating on a Mk 1 TT
Discussion
Looking for some help identifying the cause of this:
Going uphill (ie with a bit of throttle) the temp gauge rises to 110 C
Going down the other side of a hill (ie no throttle) it falls back to 90 C
Sitting in traffic with no airflow over the radiator it slowly rises back to 110 C
What's strange is that the high temp always goes to exactly the same level, just above the 110 C mark and just below the red zone. There's no wandering around with it going to different temperatures depending on how much throttle I've used.
The radiator fan is running, coolant level is good, coolant is nice and pink.
I thought that is was the water pump as, being an Audi, such an important piece of the engine is made from plastic, so I've ordered a new water pump and belt.
Are there any other things that might cause this??
Going uphill (ie with a bit of throttle) the temp gauge rises to 110 C
Going down the other side of a hill (ie no throttle) it falls back to 90 C
Sitting in traffic with no airflow over the radiator it slowly rises back to 110 C
What's strange is that the high temp always goes to exactly the same level, just above the 110 C mark and just below the red zone. There's no wandering around with it going to different temperatures depending on how much throttle I've used.
The radiator fan is running, coolant level is good, coolant is nice and pink.
I thought that is was the water pump as, being an Audi, such an important piece of the engine is made from plastic, so I've ordered a new water pump and belt.
Are there any other things that might cause this??
Worst case the main water pump failing and the car is surviving on the auxiliary electric pump. Get it sorted now fo 350-450quid tops for a cambelt waterpump an tensioner kit for added peace of mind.
Best case, you have low coolant / air lock an system needs refilling/bleeding or perhaps a new thermostat
Best case, you have low coolant / air lock an system needs refilling/bleeding or perhaps a new thermostat
aka_kerrly said:
Worst case the main water pump failing and the car is surviving on the auxiliary electric pump. Get it sorted now fo 350-450quid tops for a cambelt waterpump an tensioner kit for added peace of mind.
Best case, you have low coolant / air lock an system needs refilling/bleeding or perhaps a new thermostat
Ahh, thanks! Didn't know there was an auxiliary pump. New main pump and belt kit due to arrive today, and get fitted tomorrow.Best case, you have low coolant / air lock an system needs refilling/bleeding or perhaps a new thermostat
- * this is what I like about Pistonheads - people know a damned sight more about things than I do.
Edited by Lorne on Friday 11th January 10:53
Trevor555 said:
Just thought I'd give it a mention.
I picked one up from the auctions once, the temp guage read three quarters all the way back, engine and coolant didn't feel over heated.
Turned out to be the dash pod was faulty.
+1, my wife's old Mk1 TT read low for the four years she owned it, local Indies checked everything and no fault found, fault in the dash was all they could suggest too. Never ever gave us any problems - the fans came on when you'd expect. The fuel gauge read too high all the time as well, which was more unnerving.I picked one up from the auctions once, the temp guage read three quarters all the way back, engine and coolant didn't feel over heated.
Turned out to be the dash pod was faulty.
I had something very similar on my golf. The week before I changed my cam belt and water pump. At the time I thought oh s***t I’ve fitted a duff water pump. I thought I’d plug my diagnostics scanner in even know it had no lights up on the dash. It came up with coolant temp sensor. Replaced it and it’s been good ever since.
Oscar011 said:
I had something very similar on my golf. The week before I changed my cam belt and water pump. At the time I thought oh s***t I’ve fitted a duff water pump. I thought I’d plug my diagnostics scanner in even know it had no lights up on the dash. It came up with coolant temp sensor. Replaced it and it’s been good ever since.
that'll be my next target then.
Another possibility is oil starvation. I once had similar things happen with a car and it was oil glow. These 1.8 20v engines do have a record of oil sludge. Maybe a flush and replacement pickup is in order.
It would be good if you could find someone with VCDS, so you could read the temps directly and see if the dash telling the truth.
It would be good if you could find someone with VCDS, so you could read the temps directly and see if the dash telling the truth.
Having now exhausted my own (somewhat limited) abilities, and my local garage plugging it in and coming up with sensors as the likely cause, backed up by reading the actual hose temps when the engine said it was too hot, it's now going to said garage tomorrow to get fixed.
In the overall scheme of things, I kind of hate this car. I've kind of hated it ever since the kids got too big to fit in the back and I inherited it as a commuter mobile. But on the other hand, I kind of like it as well as it's small and compact, powerful enough, has an auto box and does everything a London commuter car should do. I keep saying next year I'll change it, but then something goes wrong, I spend a thousand quid fixing it and then decide I need to get my money's worth.
In the overall scheme of things, I kind of hate this car. I've kind of hated it ever since the kids got too big to fit in the back and I inherited it as a commuter mobile. But on the other hand, I kind of like it as well as it's small and compact, powerful enough, has an auto box and does everything a London commuter car should do. I keep saying next year I'll change it, but then something goes wrong, I spend a thousand quid fixing it and then decide I need to get my money's worth.
Edited by Lorne on Wednesday 23 January 10:56
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