Cluster Temp Gauge showing hot

[PantherS3]

Hi all. Just picked car up last night & dash temp gauge got to 90degs as it should then, just on highway driving @ 100kmh it rose to 120gdeg odd. I had to repeatedly stop the car to let it cool before dragging it home. Coolant tank full. No leaks I could see. Rad hoses didn't seem overly hot.

I've been up last night researching this but not much on the subject specific to overheating other than the usual stuff.

I'm inclined to think it's either the CTS &/or thermo. Car was just serviced weeks ago from seller.

I know this has to be unrelated but, the only thing I did was fill tank with 95 & not 98 as Servo only had 95.

Any one have any clues for me to look at?

 

[PantherS3]

The other thing noted was I never get a warning icon come up on dash?

 

[abmat]

Fuel will be unrelated. If hoses aren’t overly hot could be a faulty thermostat not opening up.

 

[PantherS3]

Fuel will be unrelated. If hoses aren’t overly hot could be a faulty thermostat not opening up.

The top hose I remember checking & it was normal running hot for a hose I guess. Definitely wasn't burning hot. I'm leaning toward it being the thermostat.

I'm leaning toward getting a Diagnostic Tool next week. I hope that'll tell me real temp readings so I can compare & perhaps it'll throw a code or 2 up? Looking @ a Topdon 500. At least it's sent from within Victoria where I am so shouldn't be too long getting here....

 

[abmat]

Was the fan running? If not could also be a faulty temp sender.

scan is the best place to start.

 

[NHN]

As above, needs diag to check readings, but pipes should be red hot tbh, not luke warm.

 

[PantherS3]

Thanks for replies guyz.

Yes abmat, thermos kick in as normal & run after engine shut down for about 5 mins or bit more.

Sorry NHN, the hoses were pretty hot but as you'd expect @ running temp. They were'nt burning hot. I took CTS plug off & washed oil off plug & smothered sensor & plug in petrol to clean engine oil spill & crud off them then, hosed them off. Sprayed some WD40 on them & took it for another run. Was fine for near 5 mins sitting @ 90deg then, steadily moved up over & over. Cools down quick but I only get 5 more mins down the road from 90deg reading then, up she climbs again..

I've bought a Topdog 500 diag tool off eBay so hopefully it'll get here next week & I'll check codes etc before I lunge into ripping stuff apart

 

[PantherS3]

Just something I find strange. When I pull over after it reaches 100-110 on the gauge needle. The fans running. The gauge drops temp back toward 90deg notch pretty quickly. I can watch it slowly descend. That would be due to fans blowing on rad I guess? I just would expect it to remain hot for @ least a minute. I can drive off again after 5 mins as it's back down to 90. same crap happens again. 5 mins later, rises up again...

 

[Garrett 69]

This might sound daft but there's no debris obscuring the radiator I suppose? Like a plastic shopping bag or such like?

 

[PantherS3]

This might sound daft but there's no debris obscuring the radiator I suppose? Like a plastic shopping bag or such like?

That's an excellent thing to check. There is nothing blocking it no. Cheers for suggestion as nit's something I wouldn't think to check for...

 

[PantherS3]

I've just returned from a test drive again. Both fans come on strong (really loud) once temp shows 100 & I pull over & stop.
Top rad hose (inc' ***' joiner hoses) are burning hot. Coolant reservoir tank is burning hot. Bottom hose is cold!

I'd say the CTS is working fine & leaning toward the thermo...

 

[PantherS3]

I got onto a VAG specialist near me today. He feels it's the water pump. I may get him to do the pump, timing belt, stat & CTS & be done with it! Over it now...

 

[Garrett 69]

My next suggestion was going to be water pump, those with plastic impellers don't tend to last

 

[PantherS3]

My next suggestion was going to be water pump, those with plastic impellers don't tend to last

Apparently, all you can get is plastic ones as there is now only one supplier. But, the bakelite material used has improved over the years. I'll be hearing from him tomorrow to get price & date for work. Also, he wants to check for codes regardless so I'll have to get it there asap.

 

[abmat]

With engine running and the cap off the expansion tank check if the coolant is flowing. I’m not then you know the problem. Pump.

 

[PantherS3]

abmat, I'll try that. The other thing I'm sure the fans don't come on until I turn off ignition. Then they come on loud. Also, belt & pump was done only 37k ago

 

[Garrett 69]

Ah, do you know what brand of pump was fitted? There are some really cheap and nasty ones out there.

 

[PantherS3]

Apparently, all pumps are plastic now, only better quality of bakelite now. The VAG guy I took car to today knows his stuff. Loves our cars. He reckons the pump was either never changed or even fitted incorrectly which can ****** blades. Definitely needs replacing, along with stat.

Here's the verdict:
No codes came up
Water pump could've been fitted wrong or, never replaced by mechanic @ the time it was done years back.
Stat is probably bad too
CTS most liklely dodgy
Battery only 90A rated (our cars need 140A) so it's stuffing my alternator. I'll need another one now
The workshop who replaced the rear rotors for RWC put old pads back on so, I'll need new pads

So, car remains with him & hopefully worked on next week.
Replacement of timing belt, water pump, stat & CTS.

So, I'll have it back soon all sorted 1000%

 

[ahtcap]

Not sure about the battery info.???

 

[Garrett 69]

A lower capacity battery won't stuff the alternator per se. It will work at full output more often but for vastly less duration because there's less cell density to charge, therefore the battery will charge quicker.

You'll only really notice the downside during colder months when it struggles to start.

The alternator, if it's not performing, may well be repairable with a new brush pack so long as there's no lateral play in the shaft. An easy way to confirm the bearings are going is uneven wear on the brushes.

 

[PantherS3]

A lower capacity battery won't stuff the alternator per se. It will work at full output more often but for vastly less duration because there's less cell density to charge, therefore the battery will charge quicker.

You'll only really notice the downside during colder months when it struggles to start.

The alternator, if it's not performing, may well be repairable with a new brush pack so long as there's no lateral play in the shaft. An easy way to confirm the bearings are going is uneven wear on the brushes.

He just tested it & found the alternator was weak or something along the lines & mentioned it had been struggling to output enough power. Said many shops have no clue as to amp ratings. I agree it sounds weird but @ least he is going over the top in checking car over as he knows I'm pretty fed up with all this so early on. He feels the seller would've been told it needed work as the coolant had been recently changed out. Just stuff he was picking up. Few other things I don't want to bore folk with. I have a sparky in the family if the alternator needs repairing as he rebuilds these & starters.

Also, I went through service history & receipts & saw the belt & pump were changed 5 years ago @ 93k. The pump was a cheap one I'd say ($112) as I know they are multiples of that now . A stat costs more & can't imagine a pump ever being $112?

 

[Garrett 69]

The pump is probably made of Chinesium.....

 

[PantherS3]

At least this new one won't be Garrett 69