Thread: Heater

The heater not getting hot can be cause by an Air lock in the system and if you have just had your Water pump seal done it is possible that the system was not bled correctly to remove all the air when refilled..

Originally Posted by Kevin B

The heater not getting hot can be cause by an Air lock in the system and if you have just had your Water pump seal done it is possible that the system was not bled correctly to remove all the air when refilled..

Having just drained and refilled my coolant I'm curious as to the best way to remove air from the cooling system.
Currently I dont have heater fixed but have a new core sitting here to install at some stage so will be needing to top up system again later.
Anyway what I did when filling up was remove cap from expansion tank and plug from radiator and fill radiator till it was full before replacing plug and topping up expansion tank. squeezed a few of the pipes trying to get any air out and that was it.

Maybe there a better way I don't know but would like to hear what others do to try to prevent air in the cooling system

Originally Posted by 3lud13

Having just drained and refilled my coolant I'm curious as to the best way to remove air from the cooling system.
Currently I dont have heater fixed but have a new core sitting here to install at some stage so will be needing to top up system again later.
Anyway what I did when filling up was remove cap from expansion tank and plug from radiator and fill radiator till it was full before replacing plug and topping up expansion tank. squeezed a few of the pipes trying to get any air out and that was it.

Maybe there a better way I don't know but would like to hear what others do to try to prevent air in the cooling system

someone can correct me if I am wrong bu ti think there is a bleed valve on the thermostat housing. i think this is the highest point in the system. i believe on the RAVE it specifies to bleed from here.

like i said i may be wrong. someone correct me if i am

Originally Posted by Fausto79

someone can correct me if I am wrong bu ti think there is a bleed valve on the thermostat housing. i think this is the highest point in the system. i believe on the RAVE it specifies to bleed from here.

like i said i may be wrong. someone correct me if i am

My guess is the valve you talk about would be the plug in top of thermostat housing (same as plug in radiator) and yes since that is the highest point I would say the cap would have to be on the expansion tank otherwise all the fluids will end up filling your expansion tank before your cooling system.

Can anyone confirm or deny this please

I just replaced my P gasket on the 300tdi. To get the air out I read in another post to undo the plug at the top of the radiator, slowly fill the expansion tank to the half way mark, wait until the coolant is at the top of the radiator (it may take several goes at filling the expansion tank to half way) then put the top radiator plug back in. It is not a fast process.

This next bit is where it gets a bit confusing. What I was reading said to undo the plug at the top of the thermostat housing, continue to slowly fill the expansion tank but what happened was that the coolant balanced out with the thermostat housing level and I had an over full expansion tank and not much coolant at the thermostat housing. In the past I've kept the expansion tank half full with the expansion tank cap on after the radiator is filled and then topped up from the thermostat housing plug and this has worked. (Some say have the car pointing up hill on a bit of a slope to help).

I ran the car stationary for about 5 minutes with the heater full on, when you are happy to take the revs to 1500, leave there for a minute, drop it back, do this several times. Massage the hoses (not sure this really works but that what I've read). At the end of all this you will have some air still in the system. I took the car for a 20-30km run with the heater full on, let it rest and then when it cooled down I topped up the expansion tank to the required level. Monitor it over the next few days and top up as required.

I'm also running an Engine Saver Low Coolant alarm as well so I'd know fairly well straight away if there wasn't enough coolant. It doesn't alarm when I do it the way I described above.

There are probably other ways to do it but this has worked for me.

Mike

Originally Posted by mike123

I ran the car stationary for about 5 minutes with the heater full on,

FYI, the heater on or off makes no difference. Coolant is constantly running through the matrix, heat is only controlled by baffles.

Originally Posted by 3lud13

My guess is the valve you talk about would be the plug in top of thermostat housing (same as plug in radiator) and yes since that is the highest point I would say the cap would have to be on the expansion tank otherwise all the fluids will end up filling your expansion tank before your cooling system.

Can anyone confirm or deny this please

A filler plug is most definitely not a valve. The item that automatically removes all the air from the top of the engine is the small hose that runs from the thermostat housing, under the air conditioner to a plastic tee thingy that acts as a kind of suction jet. The jet of coolant and air escaping from the thermostat housing draws any bubbles from the top of the radiator and deposits any extracted air into the header tank. Providing the plastic tee isn't blocked (a common problem) your bleeding happens automatically as you drive.

To check that the hose isn't blocked you just undo it from the thermostat housing and blow into it. Cold engine and cap off of course. Bubbles should appear in the header tank if it's clear.

Originally Posted by bee utey

A filler plug is most definitely not a valve. The item that automatically removes all the air from the top of the engine is the small hose that runs from the thermostat housing, under the air conditioner to a plastic tee thingy that acts as a kind of suction jet. The jet of coolant and air escaping from the thermostat housing draws any bubbles from the top of the radiator and deposits any extracted air into the header tank. Providing the plastic tee isn't blocked (a common problem) your bleeding happens automatically as you drive.

To check that the hose isn't blocked you just undo it from the thermostat housing and blow into it. Cold engine and cap off of course. Bubbles should appear in the header tank if it's clear.

sorry i meant plug. was just typing fast and not thinking, you are correct.

just wondering though. if you can bleed it from the header tank and thermo, why do you get airlocks in the heater part of things? if you bleed it as you specified will this cause the issue in the heater to go away, providing it is an airlock issue? I mean if you have a localised high point somewhere in the heating part, the air bubbles will stay stuck there wont they, even if it may not be the highest point in the system?