24 replies to this topic

[Dusky]

So if I put a matrix in the engine bay for the two pipes would that work and mout it behind the radiator???

Why? That just doesn't make sense. If you're using the car on the road you'll want a heater. If you're not it's your choice.

Connecting or blocking the take-off has implications for warm up (thermostat bypass) but putting a heater matrix under the bonnet isn't the solution.

Bypass?how? If the valve is closed water shouldnt Flow anyway?

Most/many A series heads have a bypass built in, metros used a sandwich plate. Its to allow water to flow around the whole system while the engine warms but not enough to cool it.

Doesnt answer my question. ( Not being rude) how Does the heater influence the bypass?

[Ethel]

A bypass draws water from the head and past the thermostat, so it senses the water temperature more accurately. The Metro moved the heater takeoff to the thermostat side so it can provide the same function, the Metro heater is unrestricted as the temperature is regulated by diverting the airflow. Minis with a similar system have an extra hose, with restrictor, for a bypass when the heater is off. The head gasket also has restrictions so water has to be pulled through every opening between the head and block, for more even cooling.

[Monkeyclubman]

So Im confused can I put the two pipes together or do I need to route the matrix back or should I block the heater outlet from the head???!!

[Monkeyclubman]

Just found this in a old post

06 Jan 2011
Yes you can....

The heater was originally an option on the mini...

Depending upon the pipework on the car, I think on an '85 you should have the heater pipe coming off the head on the LHS ( possibly through a tap ) which then goes to the heater and then another pipe from the heater joins into the bottom hose behind the water pump... take the pipe from the head and join it directly to the bottom hose after removing the pipe from the heater. This then isolates the heater out of the cooling system.

[Icey]

 

 

 

 

So if I put a matrix in the engine bay for the two pipes would that work and mout it behind the radiator???

Why? That just doesn't make sense. If you're using the car on the road you'll want a heater. If you're not it's your choice.

Connecting or blocking the take-off has implications for warm up (thermostat bypass) but putting a heater matrix under the bonnet isn't the solution.

Bypass?how? If the valve is closed water shouldnt Flow anyway?

Most/many A series heads have a bypass built in, metros used a sandwich plate. Its to allow water to flow around the whole system while the engine warms but not enough to cool it.

Doesnt answer my question. ( Not being rude) how Does the heater influence the bypass?

 

 

As Ethel has written, it allows water to flow out of the head and back into the block while the stat is shut. It doesn't affect the bypass, it is a bypass. I'm not sure how else I can explain it?

[nicklouse]

Ok let's clear some things up.
Some Minis have a bypass between pump and head. Not all do. But they will have a bypass somewhere else.

Some people say that running a hose from the head take off to the bottom hose is a bad idea as it stops the radiator doing much cooling.

So what happens when the heater valve is shut on the MPI?



Running a hose from the head to the bottom hose is not bad. In fact it can be good in that it pulls hot water out from the far end of the head where you can get overheating in performance motors.

Now putting a restriction in it may help reducing the flow to balance out the glow between the hose and th rad. Not that I have noticed any lack of cooling from the MPI rad.

[Dusky]

 

 

 

 

 

 

Doesnt answer my question. ( Not being rude) how Does the heater influence the bypass?

 

 

As Ethel has written, it allows water to flow out of the head and back into the block while the stat is shut. It doesn't affect the bypass, it is a bypass. I'm not sure how else I can explain it?

 

But it can hardly be seen as a bypass in a normal situation imo.
As the heater will act as a small radiator and , if the valve is shut like most people will do while their engine is running, no water will flow and it can't perform a bypass function. :) 

Anyway. 
I must say my engine started overheating when I plumbed the heater takeoff hose directly into the bottom hose.
SOlid bottom hose and blanked heater outlet and I had no overheating anymore. COuld be sheer coincidence tho.

[Spider]

So Im confused can I put the two pipes together

 

Yes, no issues.

 

If for some peculiar reason it does, block it off later. Easy to do.

 

But, it won't.

 

<Edit: Doing this - at an almost academic point - is not 'optimal'. Ideally if you want to plumb it somewhere, in to the top hose or top header tank of the radiator is better.  If you want to block it off, a blanking plate for the head and a lower hose without heater take off is available. >

Edited by Moke Spider, 02 September 2016 - 10:10 PM.

[Icey]

Anyway.

Quite! I think we're talking/typing across each other and probably trying to get to the same point!
 

Where I was trying to get to was that this needs a little more consideration than just plugging hoses up/together to ensure there is at least one bypass around the stat to allow it to function properly during warm-up. If the OP is following this, I'd be surprised, apologies for confusing the thread!

[Dusky]

Hehe
Ach, a good "discussion" is the best way to learn. And Im glad we can discuss these engines in a friendly way!:)