LOSS OF COLANT, NO SIGN OF A REASON FOR IT
you may have a blown head gasket, (yah,yah,yah,yah, i hear you say)
You may have a missfire on tickover an run fine on revup, even drive ok,
you may not have water in the oil or oil in the water,
the head gasket might only be blown between the cylinders and the water ways,
when the piston is on the way down a small amount of water will enter the cylinder bore through the blown gasket because of the presure it's under,
on the next firing stroke it will get vaporized and sent out the exaust
you may not see any water coming out of the Exaust.
And that could be the cause of your loss of collant,
the air presure generated by the pistons can equal that in the cooling system so water has nowhere to go and the water pump cant circulate the water,
hope you can follow all this , sorry to be long winded,
i have tried to explain as simply as i can, hope this helps
"i know the problem well, i had that same problem" on a diesel renault extra and it took me ages to find out what was going wrong , no water in the oil, no oil in the water, no water going out of the exaust, engine pulling well,misfire on tick over , NO HEATER MATRIX LEAKING, but the water was still disapearing, asked all the socalled knowall's all shook their heads because it did'nt have the symtoms of a blown head gasket, so it was off with it's head, rest you know about now,
a warning to any one reading this tread this problem of a head gasket going rotten can be a result of NO or WEAKENING OF ANTI FREEZE even IN THE SUMMER.
rust dont care what time of the year it is, hope this helps you or someone else,
PS I bought the van like it and never knew it had a head gasket blown untill i started to use it.
pps any spelling mistakes dont worry, my heart is in the right place.
DEN
November 2010