Impeller, Waterpump or Thermostat?

[Kris]

These are the three things that could be wrong with my car!

PROBLEM - I was driving to work when I noticed I was down on power looked at my dash to see the temp rising above 90 deg so I shat my self and pulled over. Within a minute the temp was back to normal (the fans were on) I had to drive on at about 40/50 mph to keep the temp down.

My questions are...

Could it be something other than these three things?

How much does each of these three things cost (so that I can do the cheepest first)

Thanks

 

[LCR mat]

Rahter than guessing the problem take it to a garage(or someone with vag com) will save you money in the long run.

 

[prc]

I would probably say it's the therostat. The water pumps are pretty sturdy items nowadays.

 

[ibizacupra]

you think?
Still poxy plastic impellors on all 20VT engines...

 

[prc]

you think?
Still poxy plastic impellors on all 20VT engines...

well maybe not on the 20vt, but no problem on the desiels.

 

[m0rk]

if it cooled again while running I doubt it'd be the impeller.

duff thermostat - they're just as poor quality. easy to change out though.

glad you did the sensible thing & got the heaters on full asap & reduced speed

 

[Kris]

Thanks all!

I had my car booked in for a service today at my highly trusted garage (not seat) he said that this was fairly common on the older leons and that all the thermostats had been or were being replaced whether the warrenty had run out or not!?

I spoke to seat in colchester and they had never heard this

So assuming seat won't replace it, How much is the part and is it difficult to fit? (my mechanic charges me less if his nuckles arn't bleeding after the job )

 

[Kevo]

what you describe happened to me last week it was the impeller

 

[Kris]

How much was it to fix or are you still in warrenty?

 

[Kevo]

still in warranty so sorry dont know but mine was fine when idling sat on the drive for 15 mins soon as i started driving it the temp shot up

 

[max_torque]

remember that the heater loop in on the "closed" side of the thermostat, so if putting the heater onto full hot and full fan cools the engine down this may suggest a stuck closed thermostat.

It's unusual however to have a situation where the car is fine at idle but hot when driving, usually it's a failed elec fan that gives the reverse symptoms.

I don't think being above 90degC is a problem, you need to worry if it gets above say 105 or 110 even, it is at this point that the ECU will reduce boost / throttle opening to save the day.

A slipping impeller is unlikely to fix itself at low speed / idle, however there is the possibility that at idle it will just be able to spin enough to move enough water to cool the engine, but in this case i doubt that turning the heater on will help matters.

 

[Jochen]

I would say it is the Water Pump impeller...... very common on the 1.8 20vt engines through out VW Group.
Easy way to check is to remove expansion tank cap, start engine and see if you can see coolant being pumped into top of bottle through small black hose connection, if it is not then it is 100% water pump problem. If the thermostat was stuck shut then it would just over heat idling or driving.
Hope this helps? Jochen.

 

[Carbono]

well maybe not on the 20vt, but no problem on the desiels.

oh yeah, plastic!

 

[Kris]

I would say it is the Water Pump impeller...... very common on the 1.8 20vt engines through out VW Group.
Easy way to check is to remove expansion tank cap, start engine and see if you can see coolant being pumped into top of bottle through small black hose connection, if it is not then it is 100% water pump problem. If the thermostat was stuck shut then it would just over heat idling or driving.
Hope this helps? Jochen.

I can see water entering the top or the bottle.

 

[TOm]

Just had my water pump and thermostat replaced - warning light on the dash came on, but otherwise no symptoms seen

Cost the nasty side of £400... but I did get the cam belt changed for free!

 

[Kam]

Just had my water pump and thermostat replaced - warning light on the dash came on, but otherwise no symptoms seen

Cost the nasty side of £400... but I did get the cam belt changed for free!

Hi TOm

Ouch!! That is a bit of a pinch, did you need a cambelt change or was it just convenient as they were changing the water pump??

 

[TOm]

Cam belt had to come off - so it seemed sensible to fit a new one... they're only £23 - its the labour to fit them that's the ouch bit!

 

[Kris]

Had my Thermostat changed today. I'm going to test it tonight/tommorow I hope it has solved my problem.

Apparently the job was a cu*t to do!

 

[LCR mat]

Guy in work had a problem with his water temp rising- turns out it was jsut the gauge was faulty.

 

[Kris]

ARS3!!!!

Its not my thermostat! Temp still goes too high when driving above 40/50 mph.

Could it now be the impeller or water pump