44 replies to this topic

[tmarmsi]

Having owned 2 Mpi's now in last 3 years never seen the temp gauges rise above halfway, generally speaking I assume most road cars shouldn't see their temp gauge go up so fast, there must be a problem somewhere, must be frustrating as I can see you've changed so much! These cooling systems on the Mpi's seem to work to a point then become useless surely there must be better or upgraded solutions out there? Hope you locate the problem soon must be doing your head in!

[paul_s]

Thanks all - so it sounds like it shouldn't be getting that hot (which make sense to me). Will try and get a leak test done at a garage and see if I can find any problems there.

 

In the meantime I'm looking at a couple of runabouts this weekend to take the pressure off me having to fix it! (currently my daily driver )

[Yoda]

if it does turn out to be head gasket, its only a two to three hour job, so no real need for another car?

 

Worse case it should only be off the road for a day!

[paul_s]

You're right, although it's been in the back of my mind for a while. Getting a runabout appeases the wife, as she'll get a second car to drive if need be (she doesn't like the mini). Plus, it means it'd secure the mini as a project rather than having to sell it if / when it fails the MOT next year

 

It may not seem to make sense but there's some history behind it, plus it means I get to buy another car, always fun!

[Yoda]

Careful, you may end up with a second Mini LOL

[minimaxie]

Stupid question but have you checked all the hoses are done up properly and/or not split? Could be something simple like one of the bottom hoses split ever so slightly. My MPi used to get very hot very quick too. After I had the waterpump replaced and changed the expansion tank, turned out to be a bottom hose jubilee clip got rusty and brittle from old age and started to become loose off the bottom hose that attaches to the bottom of the expansion tank. Usually, difficult to see if it is on an MPi lol

Edited by minimaxie, 13 September 2013 - 03:24 PM.

[paul_s]

Careful, you may end up with a second Mini LOL

Haha, I know! I did phone up about a MK1 GOlf cabrio this morning actually. As my 'sensible' 'practical' car you understand.

 

Stupid question but have you checked all the hoses are done up properly and/or not split? Could be something simple like one of the bottom hoses split ever so slightly. My MPi used to get very hot very quick too. After I had the waterpump replaced and changed the expansion tank, turned out to be a bottom hose jubilee clip got rusty and brittle from old age and started to become loose off the bottom hose that attaches to the bottom of the expansion tank. Usually, difficult to see if it is on an MPi lol

 

I haven't deliberately checked them, but I will give it a look. It doesn't seem to dribble or leak but that doesn't necessarily mean anything.

 

It's booked in for a leakdown test next Thursday, the earliest they can do apparently. The plot thickens..

[Ipod]

just for your information

my mpi temp gauge dont go above halfway, and fan comes on if it does creep just past.

 

EDIT, Iv aleady asked this >>>Havent read back, but are you getting heat thro the heater matrix (blead the air from it)

 

On mine after i fetteld with the hoses, i HAD to put a hose to the inlet pipe to the heater (by the bulkhead in engine bay) to get rid of the air, as normal running and squeezing of the hoses wasnt getting rid of it

Edited by Ipod, 13 September 2013 - 05:59 PM.

[eero]

My five cents as well. It normally takes me about 10 minutes of city driving to get the car up to temp, so getting so hot idling surely isn't right. When hot the needle sits just a tad under the white line, rarely going higher. When the aux fan kicks in it's about on the white line.

 

I'd suspect you've had an overpressure issue which created a leak somewhere - something somewhere had to give way. Pressure helps the coolant flow, and when it's gone, cooling is insufficient. I just fixed a small leak on my thermostat housing - it was really small, but I suspected something was amiss when I could feel very high radiant heat from the engine. 

 

Though that would still leave the original problem - how did the system get overpressurised? Faulty cap?

[Yoda]

Pressure in the system is produced by heat expanding the water in a sealed loop, Overpressure can only be the pressure cap not venting or something entering the system, for example, Gasses entering the loop from the cylinders. This normally shows itself as continuously trying to vent through the pressure cap following a very fast rise in temperature. this rapid rise is usually down to a head gasket leak, or a faulty pressure cap not sealing at around 12/13 psi (This pressure is required to raise the boiling point of the coolant), large amounts of air in the system, or a small leak. Most of these have already been mentioned here, so the problem should be solved soon if all the tests are done in a sensible order.

 

leakdown test will show up a head gasket failure, a pressure test on the cooling system will show up a leak or faulty cap. a  compression test will also help find a blown head gasket. and so will a coolant colour change test.

 

so my suspicion at the moment, mainly due to the fast rise in coolant temp, is the head gasket. It could be down to a lack of coolant + lots of air in the loop but i doubt it.

[paul_s]

I drained and re-filled the system over the weekend, as the garage isn't looking at it 'til Thursday and it's getting cold riding into work in the mornings! Took it for a drive yesterday and it did seem better.

 

I drove it to work this morning carefully, about 15 miles, and it seems to hover just over the middle of the gauge. No hot nasty smell, but I'm still a little too cautious about it. I think I'll still get it checked out, for peace of mind. Will check the coolant levels later as well, to see if anything's disappeared from it.

 

 

Incidentally, I'd bought a second tank cap just in case; that one exploded into bits when I took it off on Saturday! So my guess is that one was faulty I've put the first new one on now.

[Yoda]

 or a faulty pressure cap not sealing at around 12/13 psi (This pressure is required to raise the boiling point of the coolant),

 

 

If that cap fell apart, and you now have a new one giving you a stable temp then it looks like you found the fault.

Edited by Yoda, 17 September 2013 - 09:56 AM.

[paul_s]

Well confusingly, the cap I now have on was one that I had on when it was still overheating. I bought the second new one as a precaution in case the first one was dud. The second one is the one that exploded, so while it's stable now it *as* overheating with the other one on.

 

Maybe I should just stop poking and look the other way...

[paul_s]

…either way, as you say I think I've found / fixed the fault(s) now. Thanks for all your help!

[jamesmpi]

Send the new one back. It should never fall apart like that