8 replies to this topic

[Purple Tom]

Help!

I have a 1978 Mini Clubman, 1098 cc. I'm having (or I think i'm
having) real problems with it overheating. I bought it in July 2003,
and spent quite a while repairing the bodywork, but left the
mechanicals untouched, as it was a low mileage motor and everything
seemed in order. All i did was change the oil and filter, and give it
a visual inspection for anything out of the ordinary, it all seemed
fine.

I started to drive it, and it being the first Mini i've ever driven I
didn't have a benchmark on which to base what temperature it was
running at. I knew it seemed to be running fairly hot, with the
needle being well above 'N', and nearly into the red sometimes. I
kept driving it, and its performance improved as I used it (it had
been stood for a while when I bought it), and i assumed the
temperature it was running at was normal, as I'd heard Mini's tended
to run warm anyway.

We did things like set up the timing properly, set the carb up (was
running too weak), and a few odds and sods. On the way back from
Stanford Hall in september (a very hot day), it was getting very hot
in the convoy, so I pulled into the services, and it deposited a whole
load of water on the floor. I immediately thought water pump/hoses or
possibly burst radiator, turns out it had just dumped a load out of
the radiator overflow. I then decided the cooling system needed an
overhaul, so I changed all the hoses, water pump, transfer hose, got
the rad out and reverse flushed it, and reverse flushed the heater
too, until the water ran clear (took a while!!). This improved
matters slightly, but not much.

It wasn't so bad leading up to christmas, then it dawned on me that
the thermostat might be jammed slightly open, as it was taking eons to
warm up, and getting too hot once it had warmed up. A new thermostat
did wonders, and in the below 5 deg temperatures over christmas period
and after I was able to do 70mph constantly and it held around 'N',
sometimes a bit lower! The weather is warming up a bit now, and 65mph
sees the needle climbing past N and getting near the red. I'm
dreading the summer, as I hate to think what overheating will do to
the engine should it happen, and the last thing I want is to be stuck
in a traffic jam and the car overheat. After that stupidly long
story, what I want to ask is:

A: Am I expecting too much of an 1100 Mini to cruise at 65-70mph
without getting dangerously warm?

B: Is it worthwhile investing in one of these two or three core
radiators you see in the magazines? Or perhaps a radiator from a 1275?

C: Is it possible that waterways in the block could be blocked with
it being stood? Is the only way to unblock them to have the engine
out and head off?

D: I just read another topic on the forum about another car overheating on which the head gasket had gone, would a blown head gasket mean loss of power? The car goes like stink, and sounds fantastic, and doesn't lose water, just occasionally blows a bit out of the radiator overflow.

E: Is there anything at all that you think I may have missed which
might improve things??

Sorry for such a long message, but any help would be greatly appreciated!!

Thank you

Thomas Overton

[Bluemini]

Most of this has been coverred in the other post you read, but one thing to considder is the diff ratio your running if its getting hot at 65 mph. what kind of revs is it doing at that speed?

A better rad like a 2 or 3 core would be a big improvement!!

[Purple Tom]

Well i've had 95mph out of it, so at 65 its not straining that much to be honest. You can still talk nearly normally at that speed so I doubt its the diff ratio. I've got a week off at the end of march, and i've just acquired some 7.5" discs, so I think i'll drop the subframe off, recon all the suspension, fit new bushes, get the engine off and get a new head gasket on, and get it all cleaned and painted, and a new rad too.

Do you think its probably a slight head gasket weep?

Thanks for the very quick reply as well!! :grin:

[Bluemini]

Could be. Maybe because its been stood for a while it has started to deteriorate. Without takin it appart and lookin, its hard to say. So long as you checked everythin else it could be then the head and/or gasket is the next thing that it could be.

Good luck!

[Purple Tom]

Thank you, i'll have a crack at it, i think it will be ok to drive for another month or so, pray for good weather at the end of march!!

I have another question too, sorry to be a pain!

I have a 1978 Pick Up, that is seriously rusty but also pretty saveable too. The floor is shot both sides, so I got an 87 Advantage (MOT failure - scrap) and cut it up, I have had some sheet metal cut to the profile of inner and outer sills, and shall be welding them to the floor from the advantage. What I need to know is are Mark I minis and mark 3,4,5,6 the same width? I guess they must be as the front and rear panels etc are all interchangable. I just don't want to do all the extending work and put a heel board on the floor from the saloon if it won't fit the pick-up.

Does that make sense?? :erm:


Cheers

Thomas

[David_J]

Thomas, replying to your overheating problem….
I’ve read lots about various classics overheating and the general consensus seems to be that you can’t beat a new or re-cored radiator. Especially if a car has been left to stand and the sludge has had time to get nice and solid inside the rad. Flushing it will normally improve matters but its likely that there will still be blocked waterways in there. A good way to test this is to remove the radiator, drain it, and weigh it then compare this to the weight of a new radiator. The sludged up one will be heavier. Only problem with this is that you need to know the weight of a new radiator!

Running lean will also cause an engine to run hot.

Hope that helps.

[Bluemini]

Yes, they are all the same width, so looks like you'll be ok...

Next question... lol

[Pavel]

Check if your mixture is too lean, it might be!

Depending on money, you can invest in a 3-4 core radiator, extra electrical fan (mounted inside the left wheel arch, on the inner wing), oil cooler, in that order.

If that doesn't help, you've got SERIOUS problems with your engine. With all that equipment the engine might even run cooler than supposed to!

[Purple Tom]

Hehe, running cool would be preferable to what its doing at the mo! Its not running lean, if anything its perhaps a little bit richer than it should be. Need to get it set up properly, it recently had a stage one and its not quite right.

It used to suffer badly from running-on, but I found if you let it idle for half a minute or so before switching off it gives everything a chance to settle down and solves the problem. Also stops you looking a right prat when you walk away from a car thats still popping and banging away to iself.......................... :grin:

Thanks for the help everyone, i'll whip it all apart I think in my week off thats coming soon (end of march - seems years away!!). I'll get the engine out and stripped, rebuild it with new gaskets, give it a clean and paint while I'm at it and put a new rad in i reckon. I think i'll fit a colder thermostat and high cap water pump too. I'll keep you informed.

Oh, and thanks for the advice on the pick-up, I can proceed without fear now! I know the simpler thing to do would have been to measure something like the door step seams or something, but saying the pick-up has been used as a bottom-of-the-pile-of-scrap-over-the-winter-storage-facility is a bit of an understatement! :cheese:

Thank you!

Thomas