Hi everyone,

I've owned my 2009 Cooper S for about a week now. Less than 24 hours after buying the car, the check engine light came on, and I had a P0128 engine code. The dealership (not a Mini dealer) had the car for 2 days and replaced the thermostat. I picked it up, drove about 20 miles, stopped for some food, then got behind the wheel, started the car, and got a P112B as I was pulling onto the highway. By this time the dealership was closed, so I drove it home, cleared the codes, and checked the engine over. Coolant level was a little low. I restarted the engine, drove a little, and this time got a P0117 alert along with the P112B. I let the car sit overnight, topped off the coolant, and from that point forward, couldn't start the car without getting a P0117 error.

As part of my testing, I drove around while monitoring the ECT, and at first it was floating between 190f and 220f, with the occasional sharp drop and recovery. Then it dropped to -40f and stayed there all day. More research led me to checking the wires to the coolant temp sensor, and after pushing lightly on the plug, my scanner showed temp readings (on a cooled off engine) of around 110f.

Topped off the coolant again and took off around the neighborhood. About 2 miles into the drive, engine temp hit 225 and stayed there for most of the drive (dropping slightly at stoplights). I know the OEM thermostat is set to open at 221 degrees, so the registered coolant temps don't seem too far off what I'd expect them to be.

After my short drive tonight, the coolant level was low again. I left everything buttoned up for the night, and I'll top it off again in the AM. I've read the horror stories about warping heads and overheating engines, and to be honest I'm a little scared that I bought a seriously damaged car.

So, questions for the community:
1. Does 225 seem high for the coolant temperature or is this normal operating temp?

2. I didn't seem to have milkshake-cloudy type oil. I know what to look for there (experienced this on my first car 25 years ago). I'm concerned, though, that there seems to be some pressure building up in the cooling system - especially in the overflow reservoir - when the engine is hot. Is this normal?

3. I gave the engine a quick once-over to look for a coolant leak and didn't see anything obvious. I put down cardboard under the car and warmed up the engine for 20 minutes and didn't have anything drip down. Any ideas for other things to check?

Thanks for any guidance / suggestions / help!

-Dave

 

I'd take it back to where you bought it and get your money back. What are you doing messing around with it when it has obvious problems that weren't disclosed when you bought it? They sold you a car that immediately needed a new thermostat and is losing coolant. Sorry to be so blunt.

Yes the cooling system will run to 220-225 and is sealed so don't open it when hot.

 

So, I am reading your post and it seems likely that there are 2 things happening. With the shop didn't bleed the air out of the coolant system properly OR you are consuming coolant through the exhaust. Both will be easy to verify. You may not like what you find, but at least it won't be a mystery. Back to the shop for a coolant pressure test and bleed the system to get the air out.

 

I have a similar story with my recently purchased 2010 Cooper S re consistently drinking coolant and engine warning light on and no obvious leaks. What have you discovered to rectify?

 

So thats a bummer with the " drinking coolant". Im my experience there are a few quick checks that are easy to do. Are you handy with tools and repairs? OR going to a shop?
1. Look at all the hoses and connections for obvious crusting or leaking. Put some plastic or cardboard under car at night and see if you have drops of coolant?
2. Look at reservoir and bottle/cap itself.
3. The after-run pump is more difficult to have access to, but activates to circulate coolant to turbo when the car is hot and turned off.
4. Oil cooler seals beneath the oil filter area are well documented sources of leaks.
5. Have a hand pump and gauge hooked to the coolant bottle to be pressure tested and look for leaks while the car is elevated on jack stands or on the lift.
6. remove spark plugs and get a flashlight or scope camera to look straight down into the hole that plug was removed from. If you see sooty grey/black on the piston tops - this is normal. If you see spanky new shiny metal - your are leaking coolant into the combustion chamber and steam cleaning everything in the process - all exiting the exhaust. Not all the cylinders will look the same possibly. In this case, you may buy some time with adding a head gasket sealant.( landcover forums and BMW use this as common place). Sometimes just a tiny corner part of the gasket goes and creates either an external leak to the block or inside to the chamber.
99% of the time, the leaks can be identified and repaired easily and with little hassle. And not to worry if you cant find them- little leaks always become big ones and are found eventually.
*****just don't take off the coolant bottle top and try to add coolant when the car is warm or hot********.
Enjoy the car and update the thread when you find out whats going on.

 

Ok, here's what I've learned about my new Mini:

The check engine lights were related to a loose connector at the ECT sensor. I disconnected and reconnected the wiring harness, and it immediately switched from reporting -40 to 210 degrees. I cleared the engine codes and drove it around a bit. Engine temp was fine and the error did not come back.

As for the coolant consumption, it was pooling directly under the engine, so I was more of a mind that it was a cracked water pipe or water pump housing or bad seal in the system. I filled up to the low line on the jug and idled the engine for 10 minutes with a collector pan beneath the car. I collected about a 1/4 cup volume of coolant. There weren't any other fluids mixed in (I was looking for oil specifically), but it was clean. So I jacked up the car, broke out my go-pro camera on a selfie stick, topped off the coolant, started the car, and filmed all around under the engine looking for leaks. When I replayed the footage, I could clearly see it leaking out around the thermostat. Took the car to the dealer yesterday and they confirmed both the loose wire and that the mechanic last week had wrecked one of the o-rings on the thermostat housing. They replaced the part this morning, put 100 miles on the car to make sure everything was fine, and brought it back to me.

I've got white paper down in the garage to capture any drips, and so far the CEL has stayed off and the scanner says the last error was cleared 190 miles ago or about the time I cleared the last error.

So now I'm going to have to go drive it all over south eastern wisconsin to really make sure everything is fine. I'm hoping the worst of it is behind me and I'm on to a lot of fun motoring from this point forward.

-Dave

 

You're heading on the right direction. Thats great news!

 

Love the gopro diagnostic technique. Nice work. Hope you have everything settled down now and can enjoy many years of motoring fun.

 

First up, this is my second post and I must say I really appreciate the help I got so immediately. Wow! Well, coolant loss does not appear related to any obvious leaks in lines. I removed spark plug #4, as I was reading a misfire on #4, and looked down. The piston head was gleaming silver like it had a film of liquid on it. Car's history reveals head gasket was replaced earlier this year. So I am thinking it is still a gasket issue. I think I want to tackle it myself. I want to learn more about this fun machine, my first Mini! Thoughts?

 

you might opt for a new cylinder head if you are going to replace the gasket. RMW has the CNC machined heads, cams and updated head studs. Check out his site for all the fun thats available.

 

That seems like a bigger surgery but considering the head gasket was replaced twice in the last year (according to what records I have inherited) maybe the issue is deeper than just a faulty gasket or workmanship. Are you assuming a warped head then?

 

twice in one year would indicate that maybe the head needs to be remeasured. At a min, you can have the head checked and cleaned. And reinstalled with dealer OEM gasket set and head bolts. ARP bolts are a nice upgrade here. If the same wrench did the repair both times, perhaps his torque sequence is incorrect or he has a faulty torque wrench that has worn tolerances.
if you only have one piston that is shiney clean and the rest are carbon covered- at least you know exactly where to look. When the is off- examine the "crush" on the gasket and see where it it failing.
With the right tools and support- it can be a fun DYI. There is certainly a local machine shop to you that can handle the cleaning and measuring of the head once you RR the part and take it to them.

 

I want to learn and I am not dependent on this car so why not jump in! Do you recommend the Bentley manual as standard equipment for tackling this project?

 

Before you take anything apart - I would suggest you do some reading at ECS Tuning, Way Motor Works, Mini Mania, Out Motoring, Sneed4Speed, Detroit Tuned, RMW and others. Go to the tool sections and see what your budget will allow. Maybe you can borrow some tools. But the job is equal parts- $$ for parts, $ for labor,$ for tools,$ for manuals and patience. There are some great videos and DYI covering this. You might search craigslist for a junker $200 blown motor - just so you can practice taking the head on and off and learning how to use the timing tools. Labor in my area at dealer is $1700-2100 for RR head, plus parts and over rides.

 

Great advice! I am game so I will start doing my homework. I will also inspect the other cylinders. BTW, will I damage the engine driving some or a little on this condition?

 

park it and save your cash to move forward. Driving it is rolling the dice. Not worth it to ruin the existing block over a simple head gasket swap.

 

That's really good advice from R56devotion.

If you are going to remove/replace the head yourself then the Bentley manual is just as important as a good torque wrench - required.

 

Ordered the Bentley Manual last night! I will continue to gather info and advice. I am asking/searching around my region of mid-Nebraska for a Mini Cooper enthusiast who might be a 'close by' reference if I get stuck.

 

I just posted this message in another place on this site but tacking on to the stream here my latest update is that valve cover gasket has been replaced on this car(my mistake saying head gasket) but now I believe I am looking at a head gasket job. I was thinking that this first time project for me may be doable but my local foreign car mechanic strongly advises me not to tackle it as the special tools and know how may make this a frustrating and expensive venture. Any comment from the wisdom of the forum?

 

Lots of threads here from people who have pulled the head, replaced timing chains, etc. Search and ye shall find. I have not done it myself, but having read many of the threads it seems totally do-able. Off the top of my head, look for threads by Tigger2001, oldbrokenwind, and in the How-To subforum.

 

I have helped others with theirs in person just to be an extra set of eyes and ears, take photos and clean lots of parts. Never done it solo from start to finish. The common themes are patience, proper tools and ordering all these parts you think you will need before you start to avoid getting stuck. BE SAFE and stay organized. After the 2nd and 3rd experiences, the time needed was cut in half. Nothing replaces direct experience. I'd say with another set of hands- this is doable for you. All but having the head cleaned and measured by a professional machine shop once you take it out.

 

Lost of info here on the timing chain part: Our kits have the added bolts. Good luck with the rebuild.

https://www.northamericanmotoring.co...ce-please.html

 

O.K. get this! Showing what an amateur doctor I am . . . local foreign car mechanic has now had my Mini to diagnose/confirm problem. To my surprise he has NOT diagnosed a blown head gasket but plugged up intake valves and NO observable coolant leak can be found. What about that milky residue under the oil filler cap? He says it is condensation. What about that coolant loss? That is yet to be explained. I am learning more all the time as I seek to keep this Mini in good health.