1800: Air in cooling system

[Phid]

Also to confirm hose flow, I have it from block to heater control valve to heater core and back to cylinder head.

[c1800]

Re: Ron's Diagram--Doesn't the heater circuit go to the heater valve before the heater core? At least it does on my 71e.

[simonvolvo]

Originally Posted by c1800

Re: Ron's Diagram--Doesn't the heater circuit go to the heater valve before the heater core? At least it does on my 71e.

I agree.

In mine (Amazon, B20) the arrangement is, going along the direction of coolant flow: Back of block (elbow) to top connection of heater valve (bent part); bottom connection of heater valve (straight part) to bottom connection of heater core; top connection of heater core to pump inlet (via metal tube along the side of the block).

This seems to differ from Ron’s schema (where the core comes first and then the valve), although I can’t see that the order of core and valve can make any difference to the way the system works.

[Ron Kwas]

...are you saying I got it wrong? (...I don't mind being corrected...peer review is good!)...so I'll have to double check...it is a series circuit so as far as flow and flow restriction goes, it wouldn't really matter functionally, and it could vary with models.

Cheers

[simonvolvo]

Originally Posted by Ron Kwas

...are you saying I got it wrong?

No, it’s me who got it all wrong. Apologies.

The heater should come first and then the valve. At least for the 122S, according to the gcp catalog.

For the B20:

http://weblisher.textalk.se/gcp/2016...0&noConflict=1

and go to page 433.

It makes sense to have the valve in a cooler rather than hotter part of the circuit.

And in case we’re talking about an 1800.

See:

http://weblisher.textalk.se/gcp/2016...0&noConflict=1

and go to page 433.

Maybe Phid can figure it out from here. I can’t. Presumably the same order is required: Heater core first and then the valve.

[Phid]

Thanks for that - and yes mine is therefore wrong. Probably not the cause of my [cars] trapped air but worth getting right.

[c1800]

Looks like mine is wrong too, the factory preformed heater hoses seem to work either way! The angled nipple at the back of the head is angled to take the long hose to the valve first however. In any case the heater works just fine and I can turn the heat on and off at will with immediate response, so I'll leave it as is.

Sorry for the confusion.

[swedishandgerman]

Originally Posted by Ron Kwas

S&G;

"Is there an external pipe that returns from the heater to the front of the engine??"

Answer: Yes, there is...its the one that returns into Coolant Pump 8 on graphic I came up with a while back, for the B18/20 Cooling System:

This pipe "deteriorating" would not result in reduced supply to back of engine...a blockage could conceivably hinter Heater Loop flow which would have symptoms of poor Heater Core effectiveness, but engine supply is internal by way of Dist Pipe...ext. pipe is the return from Heater Loop.

Regarding "Waterless Coolant"...why bother?

Cheers

Thanks for clearing that up!

With reference to that there distribution pipe, that is the one that I am referring to breaking up. That's the one that runs internally. Surely if that's bad, coolant can't get to the back of the head (heater), no? Additionally, I am almost sure (woolly memory here) that our Derek UK once put up a photo of how that pipe must be properly inserted into the head.

Derek, am I barking up the wrong tree?!

All said, it's more than important to make sure there's no air in the system before looking any further!

[Derek UK]

Yes I did put up a post with pictures of the brass cooling tube. Currently I can only go back 500 posts/1st April 2016 when looking for a link to it. I've asked the mods about it. The pipe post was a further back than that.
This is rarely a problem. It is peened into place but if that was badly done it might allow the pipe to rotate a bit. An odd bit of something, maybe a piece of rubber from a dodgy old hose might also possibly get into the pipe and block it partially somewhere between the front and the back.
Did find this........
http://www.volvoforums.org.uk/showth...rass+pipe+head

[Ron Kwas]

guys;

The Dist Pipe is not round in cross section, but sort-of keyhole shaped, so under normal conditions, it cant really turn (very much) out of axial position...I've collected all I could about the pipe (including pix) here: http://www.sw-em.com/Coolant_Distrib...Pipe_Notes.htm

Cheers