Waterpump Question

Just a quick waterpump question. I bought a new one from Halfords (minispares up the road didn't have any in stock). When it came to installing it I noticed the bypass was blanked out. As I had torn down the engine I decided to use a bolt to block off the hose from the engine. The car appears to run fine and the water temp is normal but am I to suffer for this at a later date? What's the bypass for?
Many thanks!

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You have bought a 1275 waterpump for a 998, you have blocked the bypass to the head, without the bypass you will experience overheating (which is bad) because the water is not circulating around the entire engine (until the stat opens), I would recommend getting a proper 998 pump with the bypass.

Paul.

for now to save changing waterpump again so soon, you could remove the thermostat and drill 6 small holes around the flat perimeter of it, so that water can travel up through and past before the stat opens, i have done this before and had no problems at all

Thanks for the replies guys. My mini is a 1275. I installed the pump about 3 weeks ago and it hasn't overheated in fact it's running perfect. I'm just puzzled as to why that is so and whether something bad will eventually happen.

You have bought a 1275 waterpump for a 998, you have blocked the bypass to the head, without the bypass you will experience overheating (which is bad) because the water is not circulating around the entire engine (until the stat opens), I would recommend getting a proper 998 pump with the bypass.

Paul.

for now to save changing waterpump again so soon, you could remove the thermostat and drill 6 small holes around the flat perimeter of it, so that water can travel up through and past before the stat opens, i have done this before and had no problems at all

Thanks for the advice. I shall look into that.

If its a 1275 then why has it got a bottom bypass on the head? 1275's dont have that sort of bypass? they either run a sandwich plate between the stat housing and head face or as said you drill holes in the stat. They dont have that sort of bypass, unless its a 1275 with a 998 head .

Ive heard of some people not running some sort of bypass and they run fine but its bad practice to not have the water circulating though the head, the head will hold the water untill the stat opens. Does your car get up to temp very quickly?

If your stat fails it will overheat very quickly.

Paul.

Edited by Pauly, 05 September 2009 - 06:07 PM.

I've got the Opposite Problem!
Have a Water pump with the Bypass Hose on but the Cylinder Head (I think thats where it goes) There is no where for it to go! Had to Make up a Blanking Hose to stop the water pouring back out.

Many many 1275s have the bypass connection!!!!!!!!!!!! But it's EXCELLENT to do away with it - much faster warm up and far far better heater in winter. Just drill ONE 1/8" hole in the stat rim (6 is far too many) - and keep the heater valve open.

Many many 1275s have the bypass connection!!!!!!!!!!!! But it's EXCELLENT to do away with it - much faster warm up and far far better heater in winter. Just drill ONE 1/8" hole in the stat rim (6 is far too many) - and keep the heater valve open.

I agree, loads of 1275's have a bypass... and the bypass hose usually fails ... do away with it!

Chris

Exactly. Over all the years of A series production - it must have caused 100s of thousands of £s of breakdowns/ruined engines/missed appointments - maybe even injuries and deaths as people struggled at the roadside to fix the thing!!!! Good ridance to it!!

Many many 1275s have the bypass connection!!!!!!!!!!!! But it's EXCELLENT to do away with it - much faster warm up and far far better heater in winter. Just drill ONE 1/8" hole in the stat rim (6 is far too many) - and keep the heater valve open.

I agree, loads of 1275's have a bypass... and the bypass hose usually fails ... do away with it!

Chris

Alternativly don't buy the rubbish wire/cheap rubber replacement and get some decent rubber and good clips so that it doesn't perish lol thats what I did on my 998 after a split bypass hose decided to let all the water that was in the radiator escape

If its a 1275 then why has it got a bottom bypass on the head? 1275's dont have that sort of bypass? they either run a sandwich plate between the stat housing and head face or as said you drill holes in the stat. They dont have that sort of bypass, unless its a 1275 with a 998 head .

Ive heard of some people not running some sort of bypass and they run fine but its bad practice to not have the water circulating though the head, the head will hold the water untill the stat opens. Does your car get up to temp very quickly?

If your stat fails it will overheat very quickly.

Paul.

Hmm. Interesting. All these years I've assumed it's a 1275 based on paperwork with the car and the information from the DVLA but I suppose I wouldn't know if it's actually a 998 and that all the info is wrong. What check can I do on the car to confirm which engine type it is?
Cheers

Look down the back of the engine - does it have removeable covers on the cam follower chests ?

from memory you can have 3 types of water pump , 60s 850 had a shallow impeller and bypass , later and now the norm pump has a deeper impeller with bypass , A+ / metro - depends on year ect - did away with the bypass , the bypass hose is to keep a balanced temp over the lenght of the engine untill the stat opens , area around 3&4 cylinders can get alot hotter than 1&2 cylinders ,
as with most minis the original engine could have been changed over the years , so if you have a bypass hose fitted keep to that spec but use good quality hose - not the bellows thing that only lasts a year . its there for a reason .

Stick some holes in the thermostat. Done me fine for a year+ now.