26 replies to this topic

[Readers14]

I am carrying out a complete overhaul of the coolant system, as I noticed a leak a few weeks ago.

Looks like the leak is coming from the bypass hose.

I'm replacing all hoses, thermostat, thermostat housing and water pump.

 

So, what is the general consensus - Water pump with bypass or not?

 

Car is 1994 Mini Sprite, 1275cc. Had no previous cooling problems. 

[paulrockliffe]

I thought if you had no bypass anywhere the pump would terminate itself trying to push water that can't go anywhere?

 

My car has a Metro engine that has no bypass, so runs wit the heater permanently on as that circuit is the bypass.

[nicklouse]

they are not needed. but if you have the pump off a quality hose there is better than the nasty concertina version.

[ukcooper]

water problem on a mini 99% of the time its head gasket...try a compression test thotle open all puhd out cold or warm your looking for the same ruff compression on each cycinder eg 100  100  100 100

 

any engine job i replace the water pump as good prctace, hose pipe evry 3 years with coolent , and all the rest.

 

and clean the matrix out replace every 5/6 yearshets full off crap - i dont get many vreak downs ... lol..

 

id go with the bypass as you will have block rge hole in the head and it not easy with the head on

Edited by ukcooper, 22 October 2018 - 11:54 AM.

[Cooperman]

If possible delete the by-pass hose and block or blank off.

[Readers14]

water problem on a mini 99% of the time its head gasket...try a compression test thotle open all puhd out cold or warm your looking for the same ruff compression on each cycinder eg 100  100  100 100

 

any engine job i replace the water pump as good prctace, hose pipe evry 3 years with coolent , and all the rest.

 

and clean the matrix out replace every 5/6 yearshets full off crap - i dont get many vreak downs ... lol..

 

id go with the bypass as you will have block rge hole in the head and it not easy with the head on

 

I don't have a problem with the head gasket. It's leaking from the bypass hose.

I can see a split in the hose.

 

I have removed top & bottom hoses & radiator, then flushed them out plus flushed the head/block with a hose.

[Readers14]

Ok, so I decided to go down the no bypass route.
Next question is - minispares sell a plastic impeller version. Is this any better than the normal metal impeller?
I think the plastic one works out to be cheaper than the metal one.

[imack]

I've been using one of minispares plastic impeller 'super evo' pumps for a couple of years now with no issues.
Given the choice I'd run with a bypass hose fitted. I've never had a decent quality bypass hose leak in over 34 years of mini ownership, having said that, I've always replaced the bypass hose thats more than a few years old if I've had the head or pump off.
I've had a couple of heads without the bypass hose, couldn't get the blanking plug out of my current head so it has no bypass hose and I find the engine takes forever to warm up in cooler weather even with just the one small hole in the stat with the jiggle pin thing in it.
Wish I had a bypass hose.

[Readers14]

I've been using one of minispares plastic impeller 'super evo' pumps for a couple of years now with no issues.
Given the choice I'd run with a bypass hose fitted. I've never had a decent quality bypass hose leak in over 34 years of mini ownership, having said that, I've always replaced the bypass hose thats more than a few years old if I've had the head or pump off.
I've had a couple of heads without the bypass hose, couldn't get the blanking plug out of my current head so it has no bypass hose and I find the engine takes forever to warm up in cooler weather even with just the one small hole in the stat with the jiggle pin thing in it.
Wish I had a bypass hose.

Thanks for that.
My Mini only comes out during the summer months, as it’s taken off the road during autumn & winter.
So it doesn’t get regular use & when it does, the ambient temperature will be warm enough for the engine to get to operating temperature fairly quickly.

[Retro_10s]

Hi. Those concertina hoses are indeed, utter utter rubbish. 
 
I've always used the Minispares kevlar re-inforced Bypass hose, no leaks and doesn't split. but you'll have to pull the W/pump to fit it.
 
Here - > follow this link  http://www.minispare...ypass hose.aspx

[midridge2]

The concertina hose is just a emergency hose to be used temporary.

[Readers14]

So what exactly is the purpose of the bypass hose?

[Readers14]

Ah ha! http://www.dsnclassi...coolant-bypass/

[nicklouse]

not quite correct as when you turn the heater off on the later minis you stop the flow.

 

again you do not need the bypass. the water flows and the thermostat opens.

[Sprocket]

not quite correct as when you turn the heater off on the later minis you stop the flow.

 

again you do not need the bypass. the water flows and the thermostat opens.

 

Please elaborate.........

 

Every A series engine that was installed at the factory since the 1950's was fitted with a thermostat bypass of some description. The 'later Minis' are no exception.