Hi all-

Pretty sure stuff is about to get interesting. Or pathetic/miserable, one of the two.

I'm brand new to this forum, but not to automotive work or forums. I'm a business manager but love to wrench when time permits. I just bought a low mileage (60k) 2005 MCS convertible (R52) from a friend at what I thought was a great of price $5300. Near-mint condition, clear bra over much of the front, nary a scratch on the thing. The catch was it had been sitting for 18 months since the owners husband passed away. I got it and everything seemed ok, seemed to have bad fuel in it as it was rough on startup but nothing major. Changed the oil, threw in some new premium and a bottle of Techron, and buzzed on down the road.

That is until it overheated pretty severely on my wife a few days later.

I flushed/filled the radiator with G2, drove great for two days, overheated again. Changed the tstat (it was literally broken), bled the snot out of the system, ran great for 3 or 4 days, then overheated AGAIN. Bled the system again, and haven't had overheating issues since (a week or so).

BUT, I checked the oil again the other day and saw what I thought was milkiness on the stick. Jerked the oil cap off, same milkiness. Drained the oil and this is what I found. Brand new Mobile 1 synthetic, and it looks like Hershey's syrup.

Oh and I've still got a really rough idle for about 30 seconds every time I start, even after new plugs and wires.



So, three questions for you fine motorheads:

1. Is there such a thing as an intake gasket bleeding coolant into the oil on these guys?
2. What's the preferred method of testing a head gasket on a Mini? Going to do a liquid test and probably a coolant pressure test to be double sure.
3. Assuming the worst, how much trouble am I in?? Committed to doing this myself (because it's there, etc).

If I do tackle this I will chronicle the process, but I want to be well prepared in advance.

 

the oil cooler does let coolant and oil mix if the seals leak...often overlooked...
But since you a rough idle...I'd do a compression check...might give you info on the idle...easy enough to do....and might give you a definitive answer on the headgasket...might not since you have not seen steam out the tailpipe....
Yes...bleeding these cars can ba a pain...any sign it was low on coolant and that was causing after the t-stat change? Or had a bubble, aka was not fully bleed?

 

Hm, interesting. Would it be worth changing the oil cooler for giggles right off the bat?

I'll do a coolant pressure test...but are you talking about a cylinder leakdown test? I guess I could do both but don't have the cylinder test tool.

I do think I bled once and the tstat did not open properly because I had a dry reservoir that time. After a few times though once it started to get hot I would open up the bleed valve, let the air out and it would cool right down so I know air was a problem. Also had a cascading sound behind the dash...air pocket from I could tell.

 

The oil cooler is pretty easily accessible....passenger side area...looks almost like a motorcycle or aftermarket part imo...
Some have rebuilt it...kinda a crappy desgin...if the car sat and did not get 3 year coolant changes...might be worth a look...
Leak down is close...compression...just put in the guage and crank...
Two adjacent cylinders being low usually indicate a blown head gasket if the valves are ok...can also be done with a bit of oil (called wet) to eliminate ring wear as the cause...
Quick search here will give you some oil cooler info...use Google site search ...the built in search is pretty weak.

A stumblying start is semi normal for many cars...the ecu tends to have trouble adapting rapidly to seasonal fuel changes...it tends to go away after a couple tanks of fuel spring and fall...
If not, the coil often has heavy corrosion on the plugs...stock is iron with nickel plating....so look there too.

 

The chances of the oil cooler being failed bad enough to allow that much coolant to intermix with the oil is slim. I would bet you either need a head gasket or have a cracked head.

Start with a compression & leak down test, if that comes back less than definitive pull the valve cover and look for coolant around the rear most cylinder 1 head bolt.

 

If you decide to do the oil cooler, take the right front wheel and plastic wheel well liner off. Makes access waaay easier.

 

I'll post findings in the next couple of days.

And boy nkfry do I hope you're wrong about the cracked head.

 

Ok, so the head gasket blew. But why, did the head warp due to over heating? You have a few cycles of overheating so lets hope it isn't warped. When you have the head off I would take it in to have it inspected and possibly decked. But don't forget to ask why did it overheat in the first place was it just a blown head gasket or is there another reason. Be sure you check the water pump and PTO drive gears on the back of the supercharger. if the PTO gears got stripped and stopped spinning your water pump it would cause overheating. If your wife did not notice right away it could cause the head to warp and then blow the head gasket. this would not be the first case of this. While the head is off pull the supercharger and give it an inspection and top off the supercharger oil. If the gears don't have any teeth left you need a rebuild of that too or a used one.


worst case


1k for a new stock head. If yours is now warped and cannot be decked.
1K for a rebuilt supercharger because the supercharger gears chewed themselves away and are gone.


Best case. head gasket just blew and you are out $300 in parts and 8 to 10 hours of your labor.

 

Mod mini has a video on how to do everything on a r53. He does a great job, as usual, on how to fix the head gasket. It's not that hard of a job.

You can't screw up the timing if you don't turn the engine over. The only thing I don't do from the video is hang the timing chain since it's not necessary, but I'm in the minority on that one. Bently service manual also says it's designed so you don't have to hang it.

The only special tool you probably want to buy, or rent from Detroit tuned, is the cam lock tool.

 

Wow, you guys are amazing! Love an active auto forum. Will have to wait until Wednesday evening to do some testing.

And gpwpat, 8-10 hours isn't bad at all. Might even complete it this weekend of I start Thursday (assuming tests come back positive).

 

Ok folks conducted a few tests last night. Here are the results for the analysis of the panel.

First up: liquid test:



Liquid tester prior to test. Bright blue liquid.




Liquid tester after about 2-3 minutes of constant air siphoning from the coolant tank. Not solid yellow but definitely discolored. Not sure I have much confidence in this method...air siphoning from the top of the tester could have combustion gasses since the car is running during the test. Granted I'm not sure if it would be enough to discolor the fluid.


Next up: cylinder testing:



Cylinder 1 wet pressure test. About 165 PSI, best cylinder pressure. Dry the pressure was a fairly consistent 115-120. What's normal??





Cylinder 2 wet pressure test. Sorry these are so dark. Just shy of 150 PSI. Dry the pressure was a fairly consistent 115ish.




Cylinder 3 wet pressure test. Possible culprit?? About 130 PSI. Dry the pressure was 110ish.




Cylinder 4 wet pressure test. 150-155 PSI. Dry pressure was similar to others 115 or so.

So what do you think? I'm fairly confident I do have pressure issues in cylinder 3, but it doesn't seem like a catastrophic failure. Startup was VERY rough btw, and I did get smoke out of the tailpipe. I really couldn't tell if it was vapor or oil smoke, did not smell overtly like antifreeze. It did not dissipate quickly (not sure if that makes a difference).

Thanks much for any and all feedback!

 

Dry pressures are low. Going up with oil added "wet" points to bad/worn rings. But not sure if any of that is valid with exhaust gas in the coolant, which is saying "head gasket".

I would expect head gasket at a minimum, and likely a head refresh while its apart. With the head off, you can drop the oil pan to get access to the connecting rods. Pull a couple of Pistons and check the rings. My gap was in the 1.5 mm range when I did mine, and the spec is around 0.3mm.

 

Excellent, will do. Also, this thing pecks like a sewing machine. Any recommendation on fixing that while it's apart? Brother in law told me he thinks the tapping is the pressure plate as it quiets down when the clutch is pushed in.

 

If it comes and goes when you push on the clutch, then the most common is the clutch throw out bearing. Also replace the tube it rides on. Neither is expensive. Inspect the clutch pressure plate and flywheel while you have the chance.

BUT, if you are planning on doing the clutch work, you might as well pull the whole engine from the car. Will make everything easier. Much more fun & civilized way to do engine work...

 

So what's the OEM spec pressure? Scoured the Benley online manual and couldn't find anything.

 

Big thank you to Mod Mini for this video. I just replaced my head gasket and had his video taking me each step of the way. Time saver trick to keep from taking the front end to service mode, and save time, worked great. Tip from experience: check your valve cover bolts before you take the car apart. Several of mine were rusted badly. I've had to wait a few days for new bolts to arrive. The short bolts are expensive!