6 replies to this topic

[paul_s]

Hi all. Last year (around the same time, coincidentally!) I had a load of problems with overheating (http://www.theminifo...ged-and-leaking)

 

I changed a bunch of things and all seemed good. We moved recently and I haven't driven the car much at all, maybe 100 miles in the last few months. The other day I drove it about 40 miles to work, and noticed steam coming out from under the bonnet. Closer inspection, and the expansion tank had split along the seam, spewing hot water into the engine bay

 

It seems like the fan never kicked in. The expansion tank was bulging, again, under the pressure. I drove home, slowly, with the temp sensor disconnected so the fan was running constantly and it didn't seem as bad (difficult to tell I know).

 

The things I replaced last year (all bought from Minispares so I'm confident they weren't faulty):

- Expansion tank

- Cap (twice) 

- Temperature sensor

- Connector for temp sensor (as per Rover bulletin)

- Thermostat

 

For this round, I've bought a new expansion tank and cap, and some small hose for the top (just in case). I haven't bought another temp sensor as I forgot. Does anyone have any pointers or anything I should be checking with this? Last time round I took it in to the garage and they couldn't find anything wrong, also did a compression test which seemed ok.

 

For the record, the temp gauge never moved above halfway. The heater got mighty hot, so I assume the water pump is working?

[TR7]

Either the thermostat has jammed - especially as the car hasn't been used for a while. If the expansion tank has split then it is a faulty one!

If it split due to excess pressure then the pressure cap is wrong but I would expect a hose to blow/split before the expansion tank breaks?

Have you back flushed the rad to make sure there's no sediment stuck in the capillaries?

Rather than a compression test, you need a cooling system pressure test and a cylinder leak-down test. These will give an early indication of head gasket failure wheras a compression test is unlikely to until it is far more serious.

Edited by TR7, 14 August 2014 - 03:42 PM.

[paul_s]

I'm going to fully drain, flush and check the cooling system at the weekend, so I'll check the thermostat and flush the radiator while I'm at it..

 

Rather than a compression test, you need a cooling system pressure test and a cylinder leak-down test. These will give an early indication of head gasket failure wheras a compression test is unlikely to until it is far more serious.

Is that the kind of thing most garages would be able to do? Having moved I haven't found a garage yet, least of all a mini-friendly one!

[jamesquintin]

I had an issue when I was stuck in a traffic, the car started to overheat, but the fan didn't switch on (temperature gauge was normal at all times). It fully overheated just over Tower bridge. Turns out the actual fan was bust, and kept blowing the fuse. Even the AA man couldn't hard wire the fan so it was 'on' permanently, so I limped home when the traffic subsided.

Replaced the fan itself and all was fine.

 

[Fast Ivan]

it seems to me that the problem is with the expansion tank, this has failed under pressure and spewed the coolant. Its a pressurized system so any weak points will fail.

The fan appears to be operating as it should; it kicks in when the temp sensor is unplugged.

flush the system, check the thermostat etc. as already suggested, fit the new tank and go from there.

 

I'm fairly certain there were some issues with mpi expansion tanks not to long ago, might be worth speaking to minispares

[TR7]

I'm going to fully drain, flush and check the cooling system at the weekend, so I'll check the thermostat and flush the radiator while I'm at it..

 

Rather than a compression test, you need a cooling system pressure test and a cylinder leak-down test. These will give an early indication of head gasket failure wheras a compression test is unlikely to until it is far more serious.

Is that the kind of thing most garages would be able to do? Having moved I haven't found a garage yet, least of all a mini-friendly one!

Any compenent garage will have the kit to do a cooling system check.

A cylinder leak-down test can also be done without too much difficulty.

[Fossy313]

Other than that, I out mine into a garage and said that th ecu just wasn't telling the fan to kick in, although when the sensor was unplugged it kicked in, I ended up wiring in a bypass into the top hose, I bought everything twice and at £50 an expansion tank it just got too expensive,