Hopefully i can help..
Is the engine a 1.8 Turbo or just the standard 1.8?
What condition is the oil on the dipstick?
Its a standard 1.8. The oil on the dipstick looked ok but was very low. The heater did not blow out hot air only barely warm.
Hi..there thanks for your reply..
Ok..By the sounds of your description in regards to the coolant reservoir this will be most likely engine oil your seeing in there mixing with the coolant in the system..hence the reduction in oil level on the dipstick..aswell as too off course the heating issues and possible through time engine overheating issue's as the the mixture in there gets thicker causing restrictions in the heater matrix and or radiator/thermostat and of course making harder for the water pump to circulate around as it would with just coolant..There are a few reason fro that to mix like that and the first is possible oil cooler failure - some 1.8's dont have them but you can easily check on yours by locating your oil filter - where the oil filter screws onto above that you will see a square object with two coolant hoses coming and going from that oil cooler..if you do have have one of these on the oil filter housing/bracket then its looking very much like that will be your problem and causing both fluids to mix as you see..because oil pressure is allot greater then the coolant system pressure the oil will always find it way into the coolant system as opposed to the other way round..the other likely scenario is possible head gasket failure or breach between the two coolant oil passage ways and thus the two come into contact and basically the same scenario above oil into the coolant..So as above certainly check for that cooler the oil filter is screwed into..if you do have one then it would be worth having that replaced..The next problem really is having the system thoroughly flushed out and will take allot of flushing / using coolant system flushing additives etc run through the system or even household dishwasher tabs can help of course the system needs refilled/thermostat removed- the engine run upto slightly warm and then that added the engine run till upto temp to circulate it around then let it cool off the engine and then re drain all the stuff that's been dislodged etc and flush all out again thoroughly.so as above that about the only ways or the most common as per oil getting into the coolant system..I do hope this helps..If you need to ask anything else or include further info then just continue before you rate..