I bought my daughter a 07 Mini Cooper S with 53000 miles. I drove the car 300 miles home from where i bought it with no problems but only 5 days later the car ran hot on my daughter. pretty sure she drove it to the point of it shutting down. i trailered it home and replaced the thermostat and housing. it is no longer running hot but it is hard to start when cold and has a rough idle. it seems to run fine at speed. had a/z run the codes and got the following; p300, p302, p303, p300, p302, p303, p304. i can find no evidence of coolant in oil or oil in coolant. oil filler cap had no milky oil & oil seems fine. i've order some new spark plugs and will try to get a compression test done. i'm very concerned about a possible blown head gasket or a cracked or warped head
i need some advice and direction. I 'm a complete newbie with Mini's. My 15 year old daughter is heartbroken over the thought that her dream car might be a lemon.
thanks

ps-1st. post

 

Moved your post to proper section.

Sorry to hear about the overheat...Not sure it will even reach operation temp if it runs rough / wont drive any distance.

Typically with that engine, if it was driven even a short distance with red light on dash indicating a overheat condition, I'd be guessing there's damage there. Yellow or amber engine light is typically a suggestion to perform some action. But Red Light = shut down car immediately and coast to break down lane....(unless doing so will pose a risk to driver/passenger )

I would refrain from further starting / running engine until it can be checked further. Maybe have a shop perform leak down test instead of doing a compression test....If you have a scope, could pull plugs and do visual. I think Harbor Freight has a sale on scopes right now.

 

Thanks for the reply and moving my thread to it's proper location. I ran the car yesterday before seeing your reply. I put the tach in diagnostic mode with it showing actual cooling temp. which stayed around 95 c. Still seems to run great at speed but difficult to cold start.
I'm trying to find someone to do a bleed down test for me. I replaced the plugs but don't think that helped much. I haven't tried cold start with new plugs.
Thanks for your help.

 

any discoloration on plug, or any white smoke on startup?

 

I did change plugs but i'm not sure about discoloration. Maybe I can post a pic of them later. I do get a puff of white smoke at cold start up.

 

The car is now starting much better on cold starts with the new plugs. Still a little rough at idle after cold start.

 

I used a block tester to check the engine coolant for combustables and the test turned out negative. Does anyone know if that definitely means I don't have a blown head gasket or cracked head? Car is still hard to cold start and idles rough at first. I can't make the car run hot. Car has been idling now for 20-30 minutes with A/C running wide open and coolant temp staying around 93 c.
What should I check next? Closest dealer is 4 hrs away & I don't want to go that route anyway. Coolant level still fine, no coolant in oil or oil in coolant, no milky oil fill cap, negative on combustables in coolant but still hard to cold start with a some white smoke at cold start up. Runs great on road.

 

if it was mine, my next move would be a leakdown test

if it passes a leakdown test and no more codes are thrown, personally I would just drive it. If you have green colored antifreeze you'll see green tint on the plugs if it's leaking, eventually you'll see milky oil on the oil fill cap and it'll smoke worse when it has a chance to "bleed" into the cylinders after you shut the car off for a bit.

 

thanks for the reply. I guess I need to find someone to do the leak doen test for me.
Do think I could still have a blown HG or cracked head even though the combustables test was negative? I ran the test with the engine warm and cold too. Borh negative If I could just get rid of the cold start issue I would be satisfied. I tried resting the CEL by disconnecting neg terminal but the CEL come right back on. Could it be an o2 sensor or something although the only codes are for misfires?

 

they wont reset unless you have a code reader and use it to reset them

if you have an android phone just get an elm327 adapter and use torque pro

 

The water pump ( if old style ) and thermostat are both made of plastic.....

That said, seen more than a handful of prince engine MINI's requiring those to be replaced after a high temp spike....the super heated coolant MELTS some of the plastic. Saw one from a blown engine where the innerds were COMPLETELY melted like they had been in a fire....

There's a sensors attached to the thermostat which enhances the cold start....maybe it was/is somehow damaged from the incident.

 

http://www.realoem.com/bmw/enUS/show...diagId=11_3931

5 and 6 above.

But if attempting this, would highly consider replacing the whole thermostat which includes gasket, sensor and sensor gasket.....

 

Faulty thermostat is what caused the overheat. Brand new thermostat and housing installed.

 

New thermostat housing came with new sensor.

 

Was it replaced with aftermarket or OEM ?

 

The cold start issue is getting worse. I plan on doing a leak down test and compression test later today. Any tips or warnings? I've never done either test .

 

Take your time with the leakdown make sure at tdc and hold crank there

Do you have a snake camera? Might see antifreeze on piston after it gets good and hot driving and then cools down

 

#1-115 dry---168 wet

#2-85 dry---125 wet

#3-75 dry---120 wet

#4-90 dry---130 wet

Looks to me like I'm going to need an engine rebuild or a new engine. Both well beyond my mechanical abilities. I don't even know which way to turn now. What would you do?

 

I've had several shops tell me it would cost as much or more to rebuild current motor as to have it replaced with a reman engine. Best desl I've found so far is $4200-$4500 for reman engine and install. 12 month warranty.

 

yeah you got a problem, I've seen when engines are drove hot till they stop, the pistons melt onto the cylinder along the exhaust side

muratic acid will dissolve aluminum, so I was able to clean up the cylinder and reuse it, no damage to it! but not always this lucky and the labor is what kills