Header tank-white"stuff" residue in area.

[T-Cut]

Originally Posted by mileshawk56

Does not the radiator fan on mine come on when the coolant reaches a preset temperature to cool the engine? independent of the none operating low speed fan function.

No. These functions are one and the same thing. The resistor controlled slow speed is needed for both engine cooling (from 104C) and for aircon use (continuous cooling of the condenser). They aren't separate fan systems. A blown resistor removes all low speed functionality, so only 'emergency' use will operate. In other words, every time the fan starts in its current state, an 'emergency' condition exits.

TC

[mileshawk56]

Simon just a thought Ive looked at your profile and it shows you with a 1999V6. Mine is a 2004V6 and I'm wondering whether your observed results are relevant to this i.e. TCuts work on expansion tank caps indicate you could have a different expansion tank and "100" rated cap. What do you think, is it a possible explanation? Chris S.

[bl52krz]

I believe that the radiator caps were changed to 140 pascals from 100 pascals for all vehicles sometime in 2001/2

[SD1too]

Originally Posted by mileshawk56

.. you could have a different expansion tank and "100" rated cap.

Yes, I have the black expansion tank and the "100" cap.
My expansion tank differs from the later type in that it has a tube which is open to the atmosphere, controlled by the cap valve.
I don't think that the bleed tube is any different though.

Simon

[mileshawk56]

Bit late but update on white stuff! At the moment it appears the problem was an overfilled header tank. I have removed coolant to the Max mark and that has done the trick. I own up to being a bit fooled by the rather awkward method of indicating the levels and a problem where I live insomuch as there is no real level area to do a accurate check. I have done a few long runs since and no residue, but I will keep an eye on it. Thanks to all of you for your help. "A credit to the Regiment sir" Chris S.

[T-Cut]

The MAX marker isn't an absolute. If the level's up to 10mm over when cold, it'll be fine. The MIN marker is more important, yet only about 10mm (100ml in volume terms) lower.

TC

[xsport]

Originally Posted by T-Cut

The MAX marker isn't an absolute. If the level's up to 10mm over when cold, it'll be fine. The MIN marker is more important, yet only about 10mm (100ml in volume terms) lower.

TC

in my observations on coolant levels from day to day checking the header tank level ,yes it does vary quite a bit. a number of things come into play. the outside temp.the length of time left unstarted in between start up.the length of the last run. and even the position you park. even a small camber kerbside or pothole or slight incline can be read as different. i tend to park repeatedly in the exact position and direction if i can when keeping an eye on the level after any work has been carried out or if i suspect a slight leak.the core of the engine block takes a long time to cool and subsequently longer to contract coolant level . i have the kv6 (140 cap 2002) and can also echo simons observations of start up from cold without header cap.yes indeed from start up almost immediately i have the coolant circulate from the bleed pipe visible.this is i believe to vent any air and help circulation via the TWO heads and adjoining pipework during warmup during the bypass stage through the heater matrix until the stat opens. i think this is probably more prevalent and important on the v6 engine. also i think tcut is correct as to its function regarding heatsoak and maybe its not just restricted to shut down usage and is an extra escape function. ....... just my views .....

[T-Cut]

Originally Posted by xsport

i have the kv6 (140 cap 2002) and can also echo simons observations of start up from cold without header cap.yes indeed from start up almost immediately i have the coolant circulate from the bleed pipe visible.

Thanks for your observation. This doesn't happen with (most) 1.8/1.8T engines. It seems the V6 has a greater pumping force through the vent hose when the pressure cap is off. It's unclear whether it continues with the cap on and the header becomes pressurised by the hot engine. Logically it will and the header contents will have a high (head) temperature. I don't think that's been verified completely.I think I would find a varying coolant level worrying. The daily variation in ambient temperature has negligible effect on the preceived coolant level. However, my level alarm went off one morning during the cold snap when it was sub-zero. The thermal contraction of the coolant was just enough to trip it, though it does have millimetre sensitivity.

TC

[xsport]

my kv6 coolant header tank level has remained constant every day for nearly two months !! having just fitted the kaiser stat i was eager to see the effects. i work until 10.30 pm every weekday night.restart the vehicle at 11.00 am next morning. just over 12 hrs between shifts. this tells me coolant level is constant and no leaks. if however the car is left a further 24 to 36 hours at weekends then when the level is checked it has dropped to below the max mark by 2 to 2.5 mm. this happens regularly. then as soon as the car is used again regularly the coolant again returns to the max level and stays there.!! this has to be temp expansion of coolant. i doubt its pressure related. the rises and falls corelate to the readings on my hans gauge at start up taking days for the coolant to fall to near as damn it outside temps as shown on the ipk external temp. it must be that the kv6 has a much lower stored temperature release from the engine core itself compared to the 1.8 models. its probably because the block sits under inlet manifols and a large plastic upper manifold and an engine cover above that !! with padding above under bonnet and an engine undertray below .... i might be right !! .... just my take on it ...xsport.

[T-Cut]

That's exactly what I mean. The volume remains the same at the same temperature. It's if the level changes it would be a worry. The 2mm fall over a weekend means the temperature gets lower than when you run it every twelve hours. The greater the coolant inventory, the greater the header level will change against temperature. The V6 has rather more than the 1.8 but the header tanks are identical.

TC