15 replies to this topic

[hellom8]

When driving up a hill my Mini overheated and cut out.

So this weekend I replaced the thermostat and water pump and flushed and reverse flushed the system until it ran clear.

The only issues I found were a lot of rusty gunk blocking the top of the thermostat and some rust coloured water in the system.

After completing the work I ran the car up to temperature (half way on the gauge) and found it is pushing water out of the overflow and leaking oil from somewhere.

When I turn the engine off I can hear either water or oil boiling in the engine.

There is no evidence of water and oil mixing and the car runs fine, with only a loss of power going up big hills due to timing issues.

I have ordered a compression tester to get more diagnostics.

Does anyone have any ideas what might be causing the issue?.

Cheers.

Iggy.

[Cerberus]

Is the radiator cap the right one and in good condition?

 

How big an oil leak, nearly all minis leak oil, highly doubt you've got the oiling boiling,

[Yoda]

Rad cap as suggested, or may be the head gasket if not the cap.

[hellom8]

Thanks for the ideas.  It only leaks a few drops of oil after running, but when it over heated there was a puddle of oil after running.

The prevoius owner mentioned that he forgot to put the rad cap on and drove the car, so he might of put a different/wrong cap on.

Do you know what pressure cap I need to a 12HE48?.  I'm guessing 15LB?

Cheers.

Iggy.

[lewBlew]

Can you get under the car and trace the oil leak to anywhere? e.g. oil filter housing, clutch, something worse...?

 

If there is a water boiling noise then it may be head gasket, but there would be other clues e.g. rough running, steam, mayo in the oil cap so I'm not sure about that.

 

You say you've flushed the block which is good. Did you flush the radiator as well and is it in good condition? Does the cap fit securely and is the filler neck bent or damaged? My standard 998 uses a 15LB cap part no. GRC1110.

 

Mine occasionally spits out some water, like 1/3 of a cup every couple of weeks. This is usually after a long journey when I park up and the fan stops so the temperature momentarily rises and water escapes out of the cap. I've been told it's normal (probably not but hey!).

Edited by lewBlew, 20 November 2013 - 11:43 AM.

[hellom8]

Can you get under the car and trace the oil leak to anywhere? e.g. oil filter housing, clutch, something worse...?

 

If there is a water boiling noise then it may be head gasket, but there would be other clues e.g. rough running, steam, mayo in the oil cap so I'm not sure about that.

 

You say you've flushed the block which is good. Did you flush the radiator as well and is it in good condition? Does the cap fit securely and is the filler neck bent or damaged? My standard 998 uses a 15LB cap part no. GRC1110.

 

Mine occasionally spits out some water, like 1/3 of a cup every couple of weeks. This is usually after a long journey when I park up and the fan stops so the temperature momentarily rises and water escapes out of the cap. I've been told it's normal (probably not but hey!).

I've looked around the engine bay to see if I can find the point of origin but no luck so far.  I'm going to clean off the oil and look again.

I can hear a boiling/bubbling noise from the engine, but the car runs ok and no mayo, so not sure if it's the head gasket.  I will be doing a compression test hopefully this weekend so that should give me some clues.

I also flushed the rad (and reverse flushed) repeatedly until it ran clear, the rad looked to be it good condition.  The cap is not great though, its quite lose.  I got a new one today so will give it a try.

Cheers.

Iggy.

[hellom8]

I topped the anti freeze up and put the new cap on and things looked good at first, but as it started to warm up oil started running down the front side of the sump as well as a bit of anti freeze. The anti freeze doesn't appear to be coming from the overflow and the waterpump looks dry.
After running I took the engine oil cap off and I can see thin brown liquid bubbling.
I'm guessing this is water mixed with oil. I still don't have any mayo.
My compression tester should be here tomorrow hopefully, so we shall see what results it shows.
Cheers
Iggy

Edited by hellom8, 20 November 2013 - 05:21 PM.

[grumpy dad]

when you flushed the system

did you check the thermostat ?

the best way is put it in a sauce pan and bring to the boil

it should be open fully

before the water boils   

[hellom8]

I put a new thermostat in, but didn't check it before installation.

[grumpy dad]

ok try this 

is the top hose hot ?

if it is stat will be open 

and probley the cap 

[Yoda]

If you have oil and coolant running down the engine, my money is on head gasket, but it also sounds like you need to replace your rad cap. You could do a coolant pressure test if you find the head gasket is ok, by using a bike pump and pumping air into the overflow pipe just by the rad cap and listen for air leaking and looking for coolant escaping. but as i said, if you have leaks down the side of the engine then its likely to be head gasket.

[hellom8]

Did a compression test today, ran the car for 15 mins then tested each cylinder and got the following:-

1 = 50

2 = 25

3 = 50

4 = 50

I checked No2 twice and both times it came up @ 25.

My stater motor gave out after that so couldn't test with oil.

I noticed my top hose was lose and this seems to be the cause of the water leak.

However the oil leak is bad, as the car starts to get warm it starts trickling down the engine, but when it starts getting hot it appears to slow down/stop, which indicates that the gasket is leaking at warm temp but when its hot I guess expansion is forming a seal?

I'll check again with oil, but it seems like the head gasket has gone.

Cheers.

Iggy.

[KernowCooper]

If those compression figures are done with a wide open throttle and are in psi I'm surprised the car starts ? looks like the heads coming off with those figures, hom many miles has it done?

 

Did you check the valve clearances before doing the compression test

[hellom8]

The car starts and runs fine.
Figures are in PSI. I was expecting them to be triple that. But maybe the engine isn't warm enough.
I haven't checked the value clearances. I will do this as well as checking the compression again with added oil.

[KernowCooper]

If your gauge is right then you have serious issues either with the vales/seats or bores/rings worn, you should be getting another 100psi on those figures and cylinder 2 would be down then