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Well, I'm still in a sadly state with my 850 mini. The first step to prevent overheating was changing the thermostat. It made a little difference but still overheated. Then I changed the waterpump. It gave me a few more miles but in the end, at a given light stop, it kept overheating. Then I changed the radiator cap from a 14 lbs to a 7 lbs, cause my mini shop said the latter is the correct one. So I took it for a ride last friday and again overheated.

There are not many mechanics specialized in classic minis here in Mexico so no one has really accept to take it. The few ones have told me that this is the nature of a 850 mini, they will always overheat, and the only option is to install another electric ventilator. So I would like to know if you have any more ideas since I know here are some people much more familiarized to these cars.

thanx
Nick

Check the water flow through the radiator core.

Ok, the mechanic removed the thermostat again and it does run a little more. Also, as opposed to the overheating with the thermostat, it doesn't exhale a cloud of smoke thru the bonnet, but starts to smell like burnt motor oil and breaths some little smoke out the tube up in the rocker cover (by the way, should that tube be connected to something else?). Also, when trying to put some water back, the radiator spits a lot of water and makes angry and cranky noises.

I did change the water pump to a larger impeller and had to make it thinner in order to fit my 850 engine, but I'm not sure if further modification needed to be done cause the mini is is still overheating...

Hope someone can guide me here, thanx

Nick

Hi Nick,

it sounds like a blown head gasket .


and you NEVER pour cold water into a hot engine.
then you are sure to damage head/block.
if a engine is running too hot, you need to get hold of some HOT water,
or let the engine cool all the way down, before putting any water in.

Thanx for the comments, I just left it with a radiator machanic, apperantly is pretty clogged, hope this fixes the problem.

Nick

I do believe that you have most of the bits in the jig saw puzzle in all comments previous to mine. But you ought to do following actions in this order.
1. Check the ignition is correct. At the same time check gap and overall status of the hole ignition system. All very basic. Use the manual if unclear.
2. Take the advice and put in a new head gasket. Be sure all surfaces are really clean. If needed use a 1200 paper and see to you have put something to protect the liners,rings and piston from grit.
3. Old engines have often a lot of shit in the water mantels and often this grit can make a blockage in the radiator. So flush gently the new one and see to the water goes through easily.
When the radiator is overheated and you not will wait half a day to let it cole down take a drink bottle with luke warm water and pore the water gently on top of the radiator. The temp. will fall dramatically quick. Be careful when you open up to check if water is missing. Radiator caps can be bought with a valve so you can ease off the pressure. Also I presume that you perhaps live in a region where the temp. is HOT. Buy an additive that you mix with the cooling water and that will lower your temp. about 5 degrees.
Your problem always come due to bad or weak maintaining and -or service. Good Luck.
Tommy

Thanx Tommy, I had some struggle with my mini bassically cause I dont really know much about mechanics and becuase there are not many mini specialists here in mexico city. So, it would have spared me some time and money to take it directly to radiator shop. The other mechanics just move some things here and there but never checked the radiator.

Im happy to say since the radiator got serviced I can drive my mini normally, thou the guy told me It could benefit from a new core.

I'm actually thinking to upgrade to a more efficient as soon i got some cash and still can figure out if i should stick with the 7lbs cap or put back the 14lbs cap that came with the mini.

thanx
Nick

Atmospheric pressure in Mexico City is 11.1psi (14 psi @ sea level) and the boiling point of water is 92C vs. 100C. I think I would go to the 14psi radiator cap or at least a 10psi cap.

Kelley