13 replies to this topic

[Jumpinjacks]

I have installed a 88 degree thermostat on my 1994 1275 mini sprite and it used to have no thermostat in, I also changed the rad cap to a 15lbs one. It seems to run very hot now and smells very hot after taking it for a drive. Would it be advisable to drop the thermostat all together, or put a 82 or lower degree one in?
Or is this normal for a mini?

[minimanclive]

88 degrees is the correct thermostat for your Mini. There could be other things making it run hot. The ignition timing may be off, or the cooling system may need flushing out. Or another possibility is a previous owner has the fan fitted the wrong way around. That seems to happen quite a lot.

[Jumpinjacks]

It doesn't actually overheat on the temp guage, just smells and feels very hot.
Also how do you go about flushing the cooling system? ( sorry for all the stupid questions but I'm new )

Edited by Jumpinjacks, 22 August 2011 - 09:01 PM.

[bourney]

an engine will feel hot, they get scorchingly hot.

It's probably always being like that, it's just now that you have made a change to the engine you've noticed it,
Putting a thermostat in wouldn't make the engine run hotter (unless of course the thermo isnt opening). All it does is shut off (pretty much) coolant flow until the engine has warmed up (in your case, until the engine coolant has reached 88 degrees). It simply gets the engine to operating temperature quicker

[Jumpinjacks]

So it should be fine then?
I have checked the plugs and all looks fine, so no head gasket issues

[bourney]

So it should be fine then?
I have checked the plugs and all looks fine, so no head gasket issues

im not sure how you've worked out the headgasket is fine by looking at the plugs??

The plugs would indicate the A/F mixture. E.g. a white chalky plug shows the engine is running lean, chocolate brown is a good mixture and black and oily shows a rich mixture.

[Jumpinjacks]

So it should be fine then?
I have checked the plugs and all looks fine, so no head gasket issues

im not sure how you've worked out the headgasket is fine by looking at the plugs??

The plugs would indicate the A/F mixture. E.g. a white chalky plug shows the engine is running lean, chocolate brown is a good mixture and black and oily shows a rich mixture.

I was told by a local mechanic that if the headgasket was gone then one of the plugs would look different to the others

[bourney]

So it should be fine then?
I have checked the plugs and all looks fine, so no head gasket issues

im not sure how you've worked out the headgasket is fine by looking at the plugs??

The plugs would indicate the A/F mixture. E.g. a white chalky plug shows the engine is running lean, chocolate brown is a good mixture and black and oily shows a rich mixture.

I was told by a local mechanic that if the headgasket was gone then one of the plugs would look different to the others

He might be right, but personally i cant see it. Maybe if the headgasket blew on an oil passage way and into one of the chambers then yeah, one plug would be horrible and oily. But the headgasket could also blow on the water jacket and into the oil system, which wouldn't change the look of the plugs...

[Jumpinjacks]

I also checked the oil cap and in the rad, all looked ok. So it should be ok with the thermostat I have then?

[bourney]

I also checked the oil cap and in the rad, all looked ok. So it should be ok with the thermostat I have then?

Yeah, normal places to check for headgasket failuire would be crap on the oil cap, oil in your coolant, bad running, excessive blue smoke or white smoke from the exhaust.


I'm not sure if the thermostat you have in is the right one, im new to minis myself. minimanclive seems to think so though, and looks like hes being around for a bit so i'd go with him mate

[MRA]

So it should be fine then?
I have checked the plugs and all looks fine, so no head gasket issues

im not sure how you've worked out the headgasket is fine by looking at the plugs??

The plugs would indicate the A/F mixture. E.g. a white chalky plug shows the engine is running lean, chocolate brown is a good mixture and black and oily shows a rich mixture.

I was told by a local mechanic that if the headgasket was gone then one of the plugs would look different to the others

Your mechanic is right.... when a head gasket fails a big red flag comes out of plug number 3.....

It really depends on the failure mode, ie if the gasket fails at a water way to atmosphere then how can it affect the spark plug, only if the fire ring fails will there be any difference to the spark plugs, it can be noticed that the cylinder that has failed to hold a compression will result in a sooty plug, although a compression test will give yo ua better result....

Edited by mra-minis.co.uk, 23 August 2011 - 01:43 PM.

[Jumpinjacks]

This has turned into a ' Whos got the best headgasket fail knowledge thread ' lol.
Anyway, will the 15lbs rad cap be ok for my mini aswell?

[yellowmonster]

Does you Mini have a tempgauge?
What does it read when you think it "smells and feels very hot"?
What was the reason for not having a thermostat fitted in the first place?

Flushing an engine is fairly easy: go to your local service station and buy a flacon of 'engineflusher' (normally 250-ish cc's).
Wait for a while to let it cool down a bit then open your hood, gently take the cap off the radiator (watch it!) and poor the flacon into your coolingsystem.
Don't overfill the system; if it's already topped up first take some water out.
Close both cap and hood and go for a spin, make sure the engine gets upto temp.
Then let it cool down completely overnight, and pull the lower radhose off the waterpumphousing.
Push the heaterknob fully in on your dash, so that system is open too.
Remove the thermostat and engineplug (under upper enginemount/ 'dogbone', at the rear of the engine) and flush your system thoroughly sticking the gardenhose in until the water coming out again is clear and debri-free.
Then fit the plug and thermostat back, reconnect the rad-hose to the waterpump and refill with fresh coolingliquid.
Start the engine (radiatorcap off), and let it bleed itself.
Wait until it's warm, then shut off and let it cool down.
Fill the radiator upto level.
And hay-presto: it's done!

Edited by yellowmonster, 23 August 2011 - 03:40 PM.

[Jumpinjacks]

Yes it has a temp guage.
It reads just over half ( they are mpi clocks fitted, not 100% sure I trust them as the rev counter is miles off )
The old thermostat was in the car but was stuck open.