18 replies to this topic

[flamenco]

So, following my lasty topic http://www.theminifo...showtopic=87033 , I now had the head skimmed, replaced the gasket, and it now works perfect again.

However, I then went for a drive with it, and after about 15 mins (were the temperature remained normal), the temperature began to rise to about 3/4 of the guage, i.e between the Neutral and the Hot mark..it remained like that for the following 15 mins (with only very slight changes with time), and after those 15 mins (only being approximate here), the temperature climbed up to hot. Luckily a minute after it turned hot I arrived home and allowed it to cool.

What could be causing the problem? The thermostat and the waterpump are only 3 months old, I flushed the radiator and water seemed to be flowing nicely from it, there are no blockeges in the block or the head, and the headgasket is brand new.

Can anyone shed some light on what the problem could be?? I showed it to a friend of mine, who thought that the problem was that the radiator cap had a pressure of 13lbs, he told me the pressure on the cap should be less than 10???

thanks everyone in advance

[lrostoke]

A weak mixture can cause engines to run hotter. also does it feel like its getting very hot, it may just be a dodgy sender or gauge ??

Have you retorqued the head after fitting the new gasket.

The cap shouldn't really affect the temperature, If you have a 10 or 13lb cap if it blows past at either your waters already got to hot.
Also what thermostat have you got there are different temperature ratings for them, maybe you need one that opens at a lower temp.

http://www.minispare....aspx?pid=34614

Edited by lrostoke, 19 June 2008 - 06:30 PM.

[Gr4h4m]

So, following my lasty topic http://www.theminifo...showtopic=87033 , I now had the head skimmed, replaced the gasket, and it now works perfect again.

However, I then went for a drive with it, and after about 15 mins (were the temperature remained normal), the temperature began to rise to about 3/4 of the guage, i.e between the Neutral and the Hot mark..it remained like that for the following 15 mins (with only very slight changes with time), and after those 15 mins (only being approximate here), the temperature climbed up to hot. Luckily a minute after it turned hot I arrived home and allowed it to cool.

What could be causing the problem? The thermostat and the waterpump are only 3 months old, I flushed the radiator and water seemed to be flowing nicely from it, there are no blockeges in the block or the head, and the headgasket is brand new.

Can anyone shed some light on what the problem could be?? I showed it to a friend of mine, who thought that the problem was that the radiator cap had a pressure of 13lbs, he told me the pressure on the cap should be less than 10???

thanks everyone in advance

air lock? di you check the stat? top hose hot? I think the caps are 13 and 15? not sure have a google.

[Paul Wiginton]

If it got that hot it could have killed the thermostat and made it stick shut.

Paul

[rustyball]

If it got that hot it could have killed the thermostat and made it stick shut.

Paul

Change the thermostat and then see what happens.

[BJst416]

I hate to say it, but it's just really stupid to let the temps raise all the way the red line (hot mark) if you see the gauge do anything strange, pull over and shut it off.

You might have damaged your new head gasket or even worst wrapping the head again.

Thermostats are cheap as well as rad caps, why didn't you go the extra mile?

As mentioned before, a dodgy sender could be the cause too.

What was the cause of the head gasket failing first place?

[miller 666]

I hate to say it, but it's just really stupid to let the temps raise all the way the red line (hot mark) if you see the gauge do anything strange, pull over and shut it off.

You might have damaged your new head gasket or even worst wrapping the head again.

Thermostats are cheap as well as rad caps, why didn't you go the extra mile?

As mentioned before, a dodgy sender could be the cause too.

What was the cause of the head gasket failing first place?

i agree if a head gasket has gone then it has for a reason, was this not investigated when it was replaced???

[flamenco]

Thanks everyone for the replies so far

When the headgasket was replaced, it had a different radiator, the radiator it had was very old, therefore I replaced with another one, which I got from another mini (but I admit it isn't new), therefore I did try to solve the problem after fitting the new head gasket. The next step is fitting a new radiator, which should hopefully solve the problem.

As far as the thermostat is concerned, today I removed the thermostat (we don't need it as the temperautre over here is 30 degrees toay), but the temperature still got above the Normal mark. Rustyball, the temperature yesterday did not rise all the way to the hot mark, just three quarters of the way (obviously if it goes all the way to the hot mark, I would turn it off, but yesterday the temperature reached the hot mark just as I arrived the garage and was waiting for the my dad to open the door)..But it should remain on the normal mark, that's why I'm a bit worried. The radiator cap is brand new, and the sender isn't dodgy as it was on the car when I bought it, and it used to read as it should. I torqued the head gasket 2 days ago, and haven't done more than 10 miles with it, I don't think I should retorque it again that soon.

And the gasket failed in the first time because of the high temperature as well (me thinks), but I cannot say 100% as the temperature guage stopped working about two months ago, and it was last week that I installed the new one.

One last remark to rustyball, as I already said, the temperature didn't rise ALL the way to the Hot mark, it was about 3/4 of the way, what do you expect me to do, shut it off and phone the tow truck (for which I have to pay? ), when over here the distances are very short, only about 5 mins driving to go from one place to the other!!

Today used the mini again and the same thing happened, after about 15 mins driving, the temperature begins to rise above the normal mark, and stays about 3/4 of the way for the rest of the time..

cheers everyone, keep the ideas coming

Edited by flamenco, 20 June 2008 - 11:10 AM.

[mr_apples]

you should check to see if the water pumps actually moving any water, as you have taken the thermostat out i would take the rad cap off and see if water flows though the rad.



i would keep the thermostat or fit a blanking sleave as it pervents overheating of numbers 3 & 4 cylinders. without the restriction the water just rushes though the block past cylinders 1 & 2 slowing the water flow around the end of the block causing over heating.

[flamenco]

I took both hoses off and but a pipe from the water tap and statrted the car and I could see water flowing out from the top hose, so water is circulating..

never thought about the thermostat blanking sleeve, I think I'll just buy a lower temp one (a 72 degrees) and replace it with the 82 degrees one I have.

[mr_apples]

i would try flushing the coolant system, you can get small bottles of fluid you add to the water to do this.
it may just be the rads a bit silted up/corroded inside

do you have the plastic multi-bladed fan on your mini. the smooth side of the centre should point towards the engine, ribbed side towards the rad.

it may be running lean, this would make it run hotter



it could just be the hot weather and not driving along much

[BJst416]

1. Do you have the plastic multi-bladed fan on your mini. the smooth side of the centre should point towards the engine, ribbed side towards the rad.
2. it may be running lean, this would make it run hotter. Have your mixture checked.

I was going to point this out too.
If you have the plastic fan, it should sit with the nice smooth side facing the engine and the ugly side facing the rad.

I'd always avise using a thermostat, regardless of the weather. (believe me, it's hot in sunny Venezuela too and I use an 88deg)

what do you expect me to do, shut it off and phone the tow truck (for which I have to pay? ), when over here the distances are very short, only about 5 mins driving to go from one place to the other!!

I wasn't having a go with you, but if you don't want to listen to advise then what's the point of asking?
If your car it's getting way hotter than usual, shut it off, wait for it too cool a bit and THEN finish your 5 min journey.
Seems just logical to me anyways.

[mk3 Cooper S]

If you have a new gauge are you sure that it works with your sender and that the registered temp is actually 3/4 hot and not Normal?Mine reads 1/3 when it is fully warm!!
Read the output from the sender and post the results to test against

[Guess-Works.com]

My money's on the rad....

what engine are you running, what type of radiator....

[flamenco]

mk3 cooper s, if the sender or the guage are defective, would it still give a constant reading though? The reading in my case keeps increasing veery slowly, that's why I thought the problem was actually from cooling and not the guage or the sender.

BJst416, I know what you're saying, and I think it's my fault this time, but it's a bit tedious waiting for your car to get colder in a temperature of more than 30 degrees!! It's too hot inside the mini in these temperatures to stay stationary and wait for the engine to cool down!!

well, point taken, sorry if I was being a little bit harsh

So, went to the auto parts today and asked about this problem (the auto parts blokes owned minis in the past), and, after they said that it's a normal thing in this temperature, they also told me something about making an expansion tank for the radiator..I now bought a 4lbs rad cap and an expansion tank, let's hope this solves the problem

Oh, by the way, the rad cap for a mini 850 should be 7lbs and not 13, that's why the mechanic told me that 13lbs is too much for it..

Oh I also bought a 74 degrees thermostat..

Edited by flamenco, 20 June 2008 - 03:30 PM.