Posted by Stuart Smith on December 30, 2012, 12:19 am
Year of Manufacture *: 2001 ( Optional ) Engine Code or CC: 1.4 pd
Hi all
My father in law has a polo 1.4 diesel which has a problem with running too cool.
if the car is put under load ie a long hill or 80mph or hard acceleration then the temp will rise to 90 degrees but will then slowly return to 70. if the car is left running even on a hot day it wont reach 70.
we have fitted 2 thermostats 1 aftermarket 1 genuine, new water pump, plain water no coolant, and even clamped the top hose to restrict flow but nothing works.
this has been like this for 3 years but for my sanity i need to fix it. the polo is a w reg 6n2
Re: vw polo underheating
Posted by Trevor Kelleher on December 30, 2012, 3:13 pm, in reply to "vw polo underheating" Trevor Kelleher
The temperature sensor may be sending a implausible signal! have you checked its resistance at room temp?and observed its reactions on live data as the engine heats,
Re: vw polo underheating
Posted by Jon Morgan on January 2, 2013, 8:57 pm, in reply to "Re: vw polo underheating" Jonathan Morgan
You may be wasting your time trying to resolve this Stuart - below is the content of a Technical Bulletin relating to the 1.4TDI stating the experience of slow / poor performance of the heater is normal -
"Technical product information Transaction No.: 2025305/1 Service Info: Insufficient heating performance Release date: 20-Jan-2011
Customer statement / workshop findings
The engine only slowly reaches its operative temperature or it does not reach it at all; the heating performance is insufficient.
Technical background
When driving at low rpm and with small load under low outside temperatures, it happens that the highly effective TDI Diesel engines very slowly reach their operative temperatures. In these cases, the heat exchanger for heating the interior has less energy at its disposal and therefore it takes longer time before the heating reaches its full performance.
The lower temperature of the coolant does not influence the engine lifetime!
Production change
Measure
If the engine temperature increases with increasing load and reaches the operative value, it is not necessary to carry out further checks or to exchange parts (e.g. thermostat), with which you do not clearly find a defective function.
Warranty accounting instructions
Repairs based on the above claims cannot be charged as warranty claims.
The unjustifiably replaced parts will be charged back.
Re: vw polo underheating
Posted by stuart smith on March 27, 2013, 9:50 am, in reply to "Re: vw polo underheating" Stuart Smith
thanks for the vw tech sheet
never did get this to run hotter so gave up and gave it back to my father in law.
thanks again guy's
stuart
Re: vw polo underheating
Posted by Paul Howd on March 29, 2013, 1:38 pm, in reply to "Re: vw polo underheating" Paul Howd
This is of course why there is an upper limit to the practical efficiency of Motor Car engines.
A limit that we have not only reached but probabally exceeded (Well into diminishing returns territory by now IMO)
The Heat is not waste!
Some Rover 75 diesels had an Espacher heater incorporated in the "cooling" system to keep the temperatures up under light load and many other designs have electric heaters incorporated in the heater hose loop.
I haven't really looked into it (Too Lazy ) but I find myself wondering how the designers of pure EV's will keep the windscreen clear and the occupants from freezing. Sunny California is one thing. A British Winter something all together different!