A1EK

Thanks to the forum I managed to find the root cause of oil in my coolant as the O-ring seal on the oil cooler which I have now changed and the problem is fixed, however I am now having a slight issue with the car heater maintaining heat?

When I changed the oil cooler, I thoroughly flushed the coolant hoses with hot water through a hose for 30 mins, getting hot water through different combinations of disconnecting hoses until the water ran clear. I also removed the expansion tank and thoroughly cleared it out with mild soap until clean and I have flushed the car about 3 times in total.

The issue is the car starts to get warm okay after 3- 5 mins of driving but goes cold at the lights etc and does not get properly warm and maintain the heat until about 15 mins?

I have read forum posts stating that the heater core is blocked and needs flushing , however I have done this 3 times very well and there is no restriction at all when I run the hose through it?

I have bleed the system by undoing the small screw on the metal pipe whilst lifting the expansion tank high and there was some air and then once water came out sealed it.

I have pulled back the outlet pipe at the heater core when it was hot and water came out of the little hole so this should tell me there is no air there too? (PS does it matter which hose I pull back inlet or outlet?)

I am bleeding the car wrong? Do I need to bleed the system when its cold or when its at the operating temperature?

PS Although before when I had oil in the coolant from the bad oil cooler the heater was working fine so this is why I think it’s an air lock somewhere?

lyleswk

Was this an issue before the oil cooler maintenance? Even possibly?

A1EK

No even when I had the oil cooler leak the heat was ok and did not go cold when stationary.

Gingerbread man

That happens when you have stuff in the cabin heater jamming it but you said you cleaned it up.

You must have an air bubble in the heater. Here's one way of dealing with it:

Fixed my "no heat" problem.

A1EK

thanks gingerbread man, I think you were right about the air bubble, after much loosening of hoses, bleeding and squeezing I managed to get heat in the car when stationary. The coolant flows well through the heater core so knew it wasn't too blame, is just an awkward system to relieve trapped air, but it's now tropically hot!