18 replies to this topic

[Camel]

Hey, I've got a 1990 998cc Mini.

I've just finished doing a cooling system flush and clean, got it all sorted eventually. Used some radseal too but there's still white smoke coming from the exhaust, it's not an excessive amount. Not as bad as this:

Could it be related to me needing a new radiator cap as I can hear a slight hissing noise when the engine gets warmed up and there's also an air lock in the heater tubes that I'm not sure how to solve.

I do have a new head gasket but I really can't be bothered doing that at the moment, nor do I really have the time.

Any help would be much appreciated as usual.

[03jkirk]

does the mini have a brake servo? if so check you fluid levels as this can leak brake fluid into the inlet which gives off white smoke from the exshaust

Edited by 03jkirk, 03 February 2013 - 04:16 PM.

[Camel]

I'm not sure but I'll find out and check that later. Thanks.

I also replaced the thermostat too.

[Artful Dodger]

is it coming out of the exhaust or off the exhaust in the engine bay?

[Camel]

Exhaust at the back of the car.

[Gulfclubby]

As has been said, it could be coolant or brake fluid. Whichever liquid level is decreasing as you drive will be the culprit.

[Artful Dodger]

that looks and sounds like a possible head gasket. the hissing could be exhaust gasses going through the cooling system. the white smoke will be steam being boiled as it comes from the cooling jackets into the combustion chambers. remove the rocker cover, if there is loads of white mayo looking foam, tis a head gasket!

[Artful Dodger]

As has been said, it could be coolant or brake fluid. Whichever liquid level is decreasing as you drive will be the culprit.

how could brake fluid leak into the exhaust and come out the exhaust pipe at the back??

if anything was just leaking onto a manifold etc the smoke wouldnt come from the tailpipe. it would come from under the bonnet. you would also be able to see if it was coolant as it would crystallise where it was leaking onto the manifold.

[Tamworthbay]

As has been said, it could be coolant or brake fluid. Whichever liquid level is decreasing as you drive will be the culprit.

how could brake fluid leak into the exhaust and come out the exhaust pipe at the back??

If the servo diaphragm is damaged it allows brake fluid to be sucked into the inlet manifold via the servo vacuum tube. This is them burnt in the engine resulting in white smoke out the back.

[sonikk4]

If its a servo powered brake system then theoretically it could be drawn into the inlet manifold if brake fluid leaked into the servo.

Damn beaten to it.

[Artful Dodger]

As has been said, it could be coolant or brake fluid. Whichever liquid level is decreasing as you drive will be the culprit.

how could brake fluid leak into the exhaust and come out the exhaust pipe at the back??

If the servo diaphragm is damaged it allows brake fluid to be sucked into the inlet manifold via the servo vacuum tube. This is them burnt in the engine resulting in white smoke out the back.

i stand corrected!

that wouldnt cause the hissing from the rad though

[Tamworthbay]

As has been said, it could be coolant or brake fluid. Whichever liquid level is decreasing as you drive will be the culprit.

how could brake fluid leak into the exhaust and come out the exhaust pipe at the back??

If the servo diaphragm is damaged it allows brake fluid to be sucked into the inlet manifold via the servo vacuum tube. This is them burnt in the engine resulting in white smoke out the back.

i stand corrected!

that wouldnt cause the hissing from the rad though

Nope it wouldn't, but experience has told me that doesn't mean there are two unrelated and coincidental faults. On Minis expect the worst! But from the info I would also be looking at head gasket first.

[Camel]

Brake fluid level is the same as it always has been.

And i have been losing coolant, but whenever it goes down its because it's all come out of the overflow pipe.

Looked into the oil cap and could see bits of oil on top of stuff that hadn't drained down yet but no foamy white stuff. Will take the rocker cover off another day when it's lighter.

[jonny95]

the hissing could just be a dodgy radiator cap

[Gulfclubby]

As has been said, it could be coolant or brake fluid. Whichever liquid level is decreasing as you drive will be the culprit.

how could brake fluid leak into the exhaust and come out the exhaust pipe at the back??

If the servo diaphragm is damaged it allows brake fluid to be sucked into the inlet manifold via the servo vacuum tube. This is them burnt in the engine resulting in white smoke out the back.

What he said. Sadly, fixing a broken servo is more complicated than replacing a head gasket. But from what we gathered so far, it may well be the head gasket. Not all head gasket failures are equal. It can just be a breach between two piston bores, or a breach of the coolant ducts into a bore, or from the oil gallery into a bore, or even from coolant to oil only, in theory.
If you suspect coolant may be leaking into one or several piston bores, you can check the coolant in the radiator for exhaust gas particles with a chemical test that will be available from a good car parts shop.