Cooling problems

timwilky · Post by **timwilky** » Wed Aug 09, 2006 1:28 pm

Last year the daughters R reg 1.4 polo developed a hole in the thermostat housing. I changed the housing at the time but since then the heater has never got hot. I took the matrix out 3 weeks ago and flushed it just in case any crud had blocked it during the overheating exercise of last year.

Today she has had to be recovered as it overheated again. I have taken off the housing and tested the thermostat opens correctly when in a pan of boiling water.

Reading the cooling system description in my Haynes it is a little confusing and I am wondering if pipes have been crossed at some point. Does the pipe from in line with the thermostat go to the bottom hose and the pipe in line with the cylinder head coolant port go to the top hose (This is how mine is currently set) which would suggest that water is being pumped through the head, through the rad and then unable to return because the thermostat is closed. I would have thought this wrong as the rad would therefore be pressurised.

Irrespective of the above, do polo water pumps fail. The current problem is indicative of a failed pump. Car has done 60,000 miles.

oh by the way first post on this forum, I did a quick search, whilst it is obvious that the thermostat housing is a known weak point on this car, I could not find anything to indicate a known problem with the water pump.

Any advice/pointers on my cooling problems would be gratfully apreciated

willy g · Post by **willy g** » Wed Aug 09, 2006 1:44 pm

I had a failed thermostat housing in the winter an if i remember corectly the pipe with thermosat on goe,s in the top of the radiator!!
Water pumps do fail mate the vains of the pump are plastic and can snap1

timwilky · Post by **timwilky** » Wed Aug 09, 2006 4:48 pm

well just wiped out the water pump, ball ache job having to remove timing belt etc. just check. Well impellor dropped of the pump shaft as I removed it. Â£25 for a replacement. Is that a good price or have I just been robbed. BTW the replacement comes with a brass impellor

dragon_green · Post by **dragon_green** » Wed Aug 09, 2006 8:21 pm

Â£25 doesn't sound too bad to me.

by the way, the interval for changing the timing belt on a 6n is 60,000 miles, has yours been done? may as well do it, whilst you're there.

timwilky · Post by **timwilky** » Wed Aug 09, 2006 9:54 pm

yep, timing belt done 500 miles ago. I wish I had done the water pump at the same time. Still nice to have heating in her car for the first time this year.

I guess that the pump had only just been working as it was not until today that overheating had occured. If anyone can give me a definate answer on which hose goes where, it will only take you a minute to check. I would appreciate it.