10 replies to this topic

[georgegannon]

Hi guys, i have an overheating issue with my 1990 mini city. 

 

it started to happen randomly about a week or so ago.. 

 

would be fine for about half a mile, then all of a sudden the engine gets really really hot.. shoots the gauge right up over the half way point, even bright and early in the morning. 

then after around 5-10 more miles.. its basically at the hottest it can get. 

 

i thought maybe i had a faulty temp gauge, but actually the whole car does get really hot. 

the heater unit is almost too hot to touch. 

 

im worried to drive it any further than work in the mornings now.

im usueless when it comes to mechanics, can anyone give me some tips on how to prevent/fix this? 

again, im not sure what the issues is im afraid! 

 

what could it be? and how can i fix it on the cheap? 

 

PLEASE HELP! i dont want her to die! 

 

thanks

[SecretSugar]

Have you checked your radiator and made sure there is no leaks etc and that its not empty? You will see it dripping under the car if there is one.

[jime17]

Are you sure its properly overheating. Not to sound patronising but you are more exposed to the engine temperatures inside the car than with modern cars. The heater shroud can get quite hot.

That said ....

If its got water in and its not leaking it could be the thermostat stuck closed. This would stop the flow of water into the rad. Is the top of the rad getting hot? Don't open it though until the engine is cool or you could scald yourself.

Edited by jime17, 05 September 2013 - 03:13 PM.

[georgegannon]

thanks guys!

 

ok so again bare with me because im terrible with mechanics and what not.. 

 

is it worth waiting till the car is cold, opening up the rad and checking if water is there? should it be full to the top? 

 

if it has water in it.. what else could be the problem? where is the thermostat located?

 

 thanks again for all your help!

[jime17]

Yes check when cool. It should be filled to the top of the wire loops. You will know them when you see them. If you over fill it it will blow out of the overflow pipe on the filler neck when the engine gets hot. This may be confused for a leaking cooling system.

The thermostat is at the engine end of the short pipe that connects to the top of the rad. Its under the silver dome shaped thing that pipe is connected to and has 3 bolts around its edge securing it to the cylinder head.

Google images mini thermostat housing and id imagine it would show you some.

[georgegannon]

Thanks ever so much guys.. im actually kind of hoping there is a rad leak.. andthat it just needs topping up.. this is an easy procedure. 

i just hate not knowing what the problem is! 

esspecially as im not mechanically minded, i worry that its the worst! 

 

thanks again guys, i will have a look, hopefully a leak or just need a thermostat or something! 

[jime17]

Thermostat isn't a big job if its that. You just need the tools and take your time. Use lots of plus gas to try and avoid shearing the studs

[finch661]

there is a section in haynes about removing and testing the thermostat - as said above, three bolts to remove the therostat housing and put the thermosts in a bowl of boiling water. you should see the thermostat open in the heat - if not then its goosed. before doing this, start the car up and wait to the engine gets hot and feel the top radiator hose. if it gets warm then the thermostst is working.

 

another thought could be the water pump. i had really bad overheating propblems, and replaced the thermostat and temp sensor. i happened to read the minimag engine strip down guide and they mentioned that there were cheap after market water pumps used in th 90's that didnt pump the water round fast enough. turns out i had one of the cheap pumps. replaced with a new minispares water pump and never had a proplem since!

[georgegannon]

thanks for all your help. 

i feel like im a little out my depth haha. i put more water in the rad yesterday as i couldnt see a water line when i looked. 

this didnt seem to help. 

 

i will look into the thermostat!! hopefully not the pump! saying that im not even sure which job is more difficult haha. 

 

thanks though guys! really appreciate your help! 

[Yoda]

First thing to check would be the radiator cap. If it is not sealing correctly, then there will be no pressure build up in the cooling system and the water will boil at a lower temperature. to test this you can put air in the system via the overflow and see if you hear air leaking anywhere, or run the car up to temperature and if a fair bit of water comes out of the overflow and the temperature keeps rising, then suspect the rad cap. Its a common enough fault that is often overlooked.

Once you can confirm that the cap is ok, then its time to investigate other possibilities rather than taking stuff off willy nilly.

[Rog46]

Your car is now 23 years old so it could also be sludge in the system, restricting the water flow and needing a good flush out. It's worth doing this if you have to drain the system for any reason!