Have 03 s and have blown 2 heater cores in 2 months, hopefully 2 duds but open to any suggestions and what to look for... Mini dealership replaced core and did pressure check, everything is good.. I was told maybe blown head gasket or cracked head but how do you test this

 

Hmmm....

I've replaced one core on my '04 MCS - seems you've had a rotten run of luck. Tough to drive with fog on the inside of the windscreen and the stink of coolant in the car huh.

I'm really struggling to posit any cause/effect relationship between the motor and the heater coil where a fault in the engine cooling system could be triggering this though. IMHO the heater coil gets hot coolant at pressure via the plumbing, and that's pretty much it...

To your question though, a compression check would be a good start. In addition if there is a gasket issue I'd expect to find brown scum floating in the coolant overflow reservoir and/or some crap hiding on the bottom of the sump which would be detectable on the drain step of an oil change, just as the old oil starts to leave the sump (water being heavier than oil).

Fingers crossed for you that this inquiry is just justifiable paranoia, and not further issues actually exist.

Kind regards,

Charlie

 

Tough to drive with fog on the inside of the windscreen and the stink of coolant in the car huh.

well, a couple of days ago i'm having this problem on my 2005 MCS (55.000 miles). Also found that it is consuming all its coolant and that the radiator fan is kicking in more often....
i'd appreciate anyone guiding me in how to tell if it is a bad heating core or what do i need to check before taking the car to the mechanic?

best regards,

 

the heater core is located underneath the center console. If it leaks, then coolant will end up at your feet on either side of the front seats. There is a panel by your right foot when sitting in the driver's seat that has like 3 T25 screws holding it in place. You may be able to spot a leak if you remove that panel.

A coolant pressure tester is used to determine coolant leaks- it pressurizes the system and one can visibly pinpoint the source of a leak. this tool is somewhat pricey but can be sourced through some auto parts stores.

A block tester is used to determine a compromised head gasket. This tool sits atop either the radiator cap- or overflow container on the S models- it uses a fluid solution that changes color if detecting combustion gasses within the cooling system- indicating a broken head gasket or cracked head. This tool is cheap, IIRC, and is available at most auto parts stores.

Are you losing coolant? Overheating? Im surprised the dealer didnt block test your car while they did the coolant pressure test. It only takes a few minutes to perform.

Good luck, sir.

 

Well, i found a like green pond of coolant under my floormat....so it indicates i'm having trouble with the heat core, so off to the mechanic to check if it the core itself or the hoses....
As i had a few overheating events, should i also ask for a block test to check for a eventual head gasket problem?

 

Well what was the verdict?

 

indeed, core leaking...took it out and still waiting to buy the replacement, no hurry, as it is summer down here!!!!