26 replies to this topic

[simonh]

Hi there

I bought a 94 L reg 1275cc mini sprite a week ago, 500 miles later and I’ve sprung a leak. I should start by saying that I am not at all experienced with minis or mechanics in general! The leak is coming from the top of the engine behind the cylinder head at the right hand side where the bottom radiator hose appears to connect, there is also a small hose right in front of this, which my local scrapper advised was a bypass hose, (just before telling me he didn’t have one in!) however I am now a little confused as reading some of the older topics its reads as though a 1275 shouldn't actually have a bypass hose on it! Can any one out there help please? Should my model have a bypass hose as standard? If so, what’s the problem with these concertina types that I’ve seen mentioned? If there are as useless as I’ve read, what it the best alternative to use please? One final thing, as a TOTAL novice, how difficult a job is this going to be and how much of the engine/engine parts will I need to remove to get the kind of access required?

Cheers Simon

[pikey7]

a 94 should have the A+ engine which doesn't have the bypass hose. Are you sure it goes to the head, and hasn't just had a bolt stuck in the end of it to block off the water pump? (the A+ pump has the fitting but not cast open (and consequently no hose needed), and sometimes people fit A-series pumps which do have the hole, and block it off by fitting a hose, and then sticking/clamping something down it!)

Anyhow, if it has the "bolt" in it, it may be easier in the long run to spend £20 and have a proper water pump fitted, although you can just get a new hose, and do the same "bodge".

If it does indeed have a bypass hose that goes to the head, then you can fix it one of two ways. Use the concertina hose (which as you say, many do not like), or you can get a proper hose and a water pump gasket. remove the rad, remove the water pump fit the new hose and new gasket, and reassemble. Some do it by changing the hose by removing the head which seems a little drastic to me, although the rad can be a PITA to remove (especialy the lower hose to the rad).

Just out of curiosity aswell, post up the engine number (top RH corner (as you look at it) of the block) so we can maybe try to ascertain if it is the right engine for the car.......


Oh, and welcome!

[simonh]

Like i said, i am a novice but i do think it has a hose on there, it is jubilee clipped at each end and appears to be swolen/blown up a bit like a baloon in the middle, i cant get the engine No' now till day light, but will post it in the morning.

Thanks for that. Simon

[Pavel]

Didn't mini A+ engines have bypass hoses? I thought it was only metro engines that did away with them. Definitely sounds like a bypass hose from simonh's description!

Incidentally the bypass hose is often regarded as one of the worst jobs on the mini! (sorry mate). You don't have to take anything apart really, it's a matter of undo the clips get rid of the hose and somehow fit the new one in, tighten clips! but its VERY tricky and fiddly so may take you a while.

[Dan]

Nope, it shouldn't have a bypass hose on it. It should have a sandwich plate under the thermostat feeding the heater and inlet manifold instead of this so it shouldn't need a bypass.

The concertina hose is weaker than a standard coolant hose, it's not got reinforcement in it and is a very thin walled plastic substance rather than proper rubber. It weakens on the concertina sections as it flexes so it has a tendency to burst. A better raplacement is a normal section of coolant/heater hose the right size, but you need to drop the water pump to fit it. Since removing the water pump is the easiest way to change the hose anyway that doesn't matter too much.

There is a genuine cap to cover the bypass inlet on the water pump in case a standard early pump is used to replace the original pump on late engines. Part number CAM4126, needs a fuel type hose clip to hold it on.

[Sprocket]

With the A+ Carbed 1275 Minis that had these engines fitted as standard will all have a bypass hose. Reason, there is no other way for circulation of coolant when the thermostat is closed. On the Metro coolant is circulated through the expantion tank from the sandwich plate before the thermostat hence why the bypass hose was omitted. If you remove the bypass hose and the coolant has no way of circulating you will need to drill a few small holes around the flat section of the thermostat. A 94 Mini carbed engine will have a sandwich plate for the heater take off, but will not circulate if the heater valve is closed.

Just my two pence worth because I had a real big argument with one of the Harper brothers at MiniSport back in 1999 when the gave me a stage three head with no bypass, went to fit it and found the 94 Mayfair we had, has one. Took it back and got them to swap it for a head with, where the argument began.

Im sure some one will again want to debate this with me, but I am staying with my thoughts that if Rover deemed it necisary to fit it on a road car, then it shall stay as the car was used dayly. There is a valid reason for it

If when you do replace it, take the pump off and use a piece if hose rather than one of those crappy concertena things

[Dan]

Ah, good point. I was assuming this car was SPi, don't know why really.

[pikey7]

I'll be the one to ask then! The sprite I picked up for the engine (1992, 1275, carbed) has no bypass hose. AFAIK, (checked the engine/chassis no history with the DVLA), its original. Whether the head is or not........

Of course it's my only experience with that late an A-series (i'm well prepared to not be correct!), so I'm not looking to be the one to carry on any arguements!

[miniboo]

mine is the same as yours pikey7 it also has the sandwich plate on the head

[simonh]

Well, looking at it again in daylight, it does have a hose on there, it is a carb not an SPi. As requested Pikey7, the engine No is 12A2B603 290455. Just out of interest who do you check this with?

[pikey7]

If I told you that, I'd have to kill you.......

Naaah, Guessworks has complied a very comprehensive list HERE

According to it, it does sound like the right engine number (phew).

Well, anyway, new hose and new WP gasket needed! Good luck with it! (shouldn't take that long.....)

[simonh]

Right, a few hours of messing later and the new bypass hose is fitted, if it solves any arguments the '94 1275 DOES have the bypass and it does correctley connect, its not some kind of bolted bodge. However, after all this I now have a noise coming from my fan! The bottom long bolt was a right PITA to get back in and the rad was wobbled quite a bit to make it slide into place, whats the chance that i twisted the cowl as the baldes of the fan are catching ever so slightly on 1 little part of the cowl?!?!?! To boot i've some how killed off my dial that shows the temp, fuel and the oil and batt lights so i guess im gonna be tracing wires back for a bit know to see what i dislodged!

[simonh]

Well confused! up until todays little water hose swap the gauge in the car has been fine, oil and batt light come on when ignition turned on and they both go of within a few seconds of the car being started, fuel and temp gauge both also worked. After finishing the hose replacement i took the car "round the block" and these worked as they should, i fitted the air filter back on and now the oil and batt lights dont come on with the ignition, but the batt light does now come on and stays on after a minute or so of driving, no sign of the oil light at all, temp guage lifts from just below blue onto the blue but goes no further and the petrol guage goes to half way despite their being a tank full of petrol. I dont know if its linked but the inicators and hazards also stopped working but after about 15 mins of driving and me messing with the switches, when i put the hazards on their was a funny buzzing sound from behind the dash and both hazards and indicators now work! Any ideas?????

[miniboo]

check the fan belt for the battery light thing

looks like you have knocked and dislodged some wiring, probably near the air filter

[Si'sStepdad]

check the fan belt for the battery light thing

Could that tie in with the 'fan clipping cowl' prob Simon mentioned?

Like Si said the dashboard displays were fine until after he had a bit of a test drive - I'm no better a mechanic than he is and seems like we solved one prob and created a couple of others in the process.