Hiya, thanks for allowing me on the forum.

Sorrt for lengthy thread, its about a friends car, he knows very little about engines so asked for my advice. He had car totally refurbished couple years ago hence reluctant to do too much in case he has a comeback on company. I'm a Triumph man with little experience on older Fords.

Mk1 Escort 1300xl ~ 1975, water was coming out of radiator overflow. I looked and all seemed ok, top hose and rad seemed hot but yes as it warmed up, water flowed out overflow, but temp gauge didn't read. New sensor remedied gauge and water overflowed before fully warm and this time noticed top hose/rad cold.

Took thermostat out and was staggered to find it was covered in a black gunge with lots of sediment and in the hose - it did rinse off in water but lots of sediment and black bits in sink. Checked it worked, put back and this time gauge read, top hose and rad got hot as stat opened. Can only think gunge was shielding the stat.

Told him at the least it needs a good flush to get rid of rust sediment and then quality antifreeze but more worried about the black gunge, could it be oil contanination - I'd guess from feed to head? Dipstick and filler cap nice and clean.

Any thoughts welcomed.

Cheers

Paul