overheating light on dash

[jackg]

It came on today for the first time.

Temperature was high, although I don't usually look.

Water and oil levels are ok

Rad fans were on after I stopped to lift the bonnet.

Type of driving I do is 10-15 miles once or twice a day.

170k needs a service.

Turbo has to be stripped at some point.

 

Any pointers for diagnostics please.

 

Edited 17 August, 2017 by jackg

[KenONeill]

Car may just "be hot".

 

Otherwise I'd suspect a part-blocked radiator or a failing head gasket.

[jackg]

Cam belt and water pump were last changed in 2010 at 100k, Is wear to the water pump likely to be the problem?

Edited 17 August, 2017 by jackg

[bigjohn]

After running and hot try and feel various parts of the radiator core to see if it's evenly hot everywhere to check for blockages - be careful of the fan though!

 

Also Plastic water pump impellers have been known to fail (they break up)

 

Also consider the thermostat - but with fans coming on, probably not

Edited 17 August, 2017 by bigjohn

[jackg]

Thanks will do.

Thanks to Ken as well, you made a couple of suggestions.

[bigjohn]

2 minutes ago, jackg said:

Thanks will do.

Thanks to Ken as well, you made a couple of suggestions.

 

Might be difficult in this weather - but does the heater keep working at tickover (when engine warm)! - presuming it's still full of coolant if it doesn't then waterpump issue likely  

[jackg]

Thanks again, I'll see what I can do over the weekend.

 

[kentphil1]

are you getting a steady stream of coolant coming from the return into the expansion tank when the engine is running?.

[jackg]

are you getting a steady stream of coolant coming from the return into the expansion tank when the engine is running?

 

No idea, so I will check.

[kentphil1]

You should be able to see a steady flow of pink coolant flowing out of the return outlet in the expansion tank, it may become stronger if you pick up the revs a couple of hundred rpm, but should not be sputters and spits.

 

Poor flow could be the indication that your water pump may be getting near to claiming it's pension.

 

I'm not sure what the belt interval is on the diesel, so I'm sure Ken will jump in here to confirm, but 7 years seems a bit long for a cam belt to me, as my last petrol belt done in a skoda specialist was done at just over three and a half years.

 

Do you know if your slow speed fans are working?, they should only come in at full chat when the temp is really high, the slow speed should deal with most normal driving situations.

[jackg]

2 minutes ago, kentphil1 said:

You should be able to see a steady flow of pink coolant flowing out of the return outlet in the expansion tank, it may become stronger if you pick up the revs a couple of hundred rpm, but should not be sputters and spits.

 

Poor flow could be the indication that your water pump may be getting near to claiming it's pension.

 

I'm not sure what the belt interval is on the diesel, so I'm sure Ken will jump in here to confirm, but 7 years seems a bit long for a cam belt to me, as my last petrol belt done in a skoda specialist was done at just over three and a half years.

 

Do you know if your slow speed fans are working?, they should only come in at full chat when the temp is really high, the slow speed should deal with most normal driving situations.

Thanks for the detailed info about the coolant return.

 

I don't know about the slow speed fans, another thing to check.

Edited 17 August, 2017 by jackg

[KenONeill]

@jackg - The mileage since last cambelt and water pump is more to the point than the time, since the water pump seems to last ~1.5* cambelt change interval in miles, so if we're looking at 72_000 miles since the water pump was last changed then it's a strong suspect.

[jackg]

Started the car from cold, removed the reservoir cap, I could not see any fluid returning, although I am not sure where the return pipe enters the reservoir. There was no flow of liquid or bubbles anywhere.

 

The rad fans were also on with the AC, turn off the AC and the fans stop. So not the fan controller.

Got to get prices for the cam belt, car maybe worth £600, is it worth it as the turbo needs stripping as well.

Would a poor water pump affect the functioning of the turbo?

[petrolbloke]

On 8/18/2017 at 10:05, jackg said:

Would a poor water pump affect the functioning of the turbo?

 

If it's been overheating then that could have increased the oil temperature which could increase wear on the turbo. But that could also be due to lack of servicing and/or how it has been driven.

 

If the car needs a new/recon turbo, is overheating and is due a cambelt/water pump replacement then it may not be worth it on a £600 car, but you can prolong its life a bit longer by letting it cool down if you notice the temperature getting too high.

 

First thing I'd check is the top and bottom hoses on the radiator once warmed up (carefully because of the fans!). If both hoses are not roughly the same temperature then that would suggest a problem with the flow of coolant - either a thermostat sticking closed, knackered water pump or other blockage in the system. If you find that it is one of those things then you should drain all the coolant and refill with the correct type.

[jackg]

Thank you Tom.

As I recall 18 months ago, I replaced the reservoir and added some standard antifreeze.

And now having read around the subject, that was not sensible as the coolant has to be G12+.

The coolant can gum up apparently, which may be the cause.

I am just a little reluctant to run the engine as it may cause damage without a diagnosis, but I will have a go and drive five miles or so and then check the hoses.

Toying with the idea of draining and flushing. Need some G12+ and a thermostat gasket if not a new thermostat.

[jackg]

Went for a drive.

After 10 miles the temperature crept up and the red dash light came on.

Felt top and bottom hoses, top was hot, bottom was slightly warm.

From what I read it takes a while for the bottom hose to warm up.

Turned AC on to max temp of 29C, no heat came from it.

Rad fans were on high speed when I checked the hoses.

 

 

 

Edited 20 August, 2017 by jackg

[SuperbTWM]

Sounds like the water pump isn't circulating to me, if it was the thermostat you would still get warm air through the heater matrix

Edited 20 August, 2017 by SuperbTWM

[jackg]

Flushed the rad, did not seem to make much difference, still overheats, but may  take slightly longer to do so.

Not much detritus from the rad flushing either.

Very slightly warm air in the cabin after 10 miles.

There is liquid returning into the expansion vessel but with bubbles. Burbling flow.

Quoted £370 to replace the cam belt and water pump. Did not ask whether Skoda or pattern parts.

Devil and the deep blue sea, a car I am familiar with or another one which has unknown warts.

Edited 23 August, 2017 by jackg

[jackg]

Got the cam belt and water pump replaced.

The water pump connection to the pulley which is driven by the cam belt was ruptured so the pump did not rotate at speed.

Gates cam belt kit.

Auxiliary drive belt was starting to break up as well, so that was replaced.

Mechanic said the car was pretty good otherwise.

I've got wheels again.

Edited 6 September, 2017 by jackg