Hi everyone,
‘04 R50 here, I currently have intermittent heat (every time I stop at a stop sign or red light the heat peters out) and my Engine Temp light flashes and come on then goes out after I get back up to speed. The cooling fan come on and stays on while the engine is running (and sounds awful in the process) and stays on after the car shuts off (but it sounds like it should when the engine is off). The overflow tank is full, and as far as I can tell the engine and hoses are all full of coolant. I believe this all started in the fall when I found a puddle of coolant on top of the tranny and under the car, but I never found the leak. Anyone have any experience with this kind of problem?

 

I’m going to go with a cracked thermostat housing and air somewhere in the cooling system.

 

The 'overflow' tank is an 'expansion' tank. When cold, it should only have an inch or so of coolant in it. It should not be 'full', siphon any excess off.

 

The R50 has an overflow tank, not an expansion tank like the R53. That is, the R50 tank is not pressurized and only has a single line running to it from the thermostat housing.

 

Sorry, the expansion tank is full to the cold mark is what I meant. I’m up on the lake in Ohio and it’s currently 20 degrees and I’m dealing with an overheating car... smh
I wish they would have put a temp gauge in these cars

 

The R53 has a 'hidden menu', perhaps the R50 does too'. Try this:To get a better idea of the real engine temperature if you don't have the little button on the end of the stalk, you can still use the 'secret menu'.
Hold the trip reset & turn the key on - don't start the engine - trip will show >> t e s t - press the reset to 19 - trip will show >> li on off on off - when it's off, press the button to 7 = coolant temp - don't turn the key off & start the engine. Mine runs around 96C most of the time.

I think I've attached a file that may help.

 

I guess I should explain my reasoning. To me, coolant on top of the transmission points to an issue with or near the thermostat housing that sits right above the gearbox. They're a known failure point; I had mine replaced under warranty years ago due to a crack. It took the dealership a couple of days to find the leak.

Have you actually checked the coolant level under the pressure cap? If there is a leak, the system may not be drawing coolant back out of the overflow tank.

 

I did check the pressure cap, that tube is completely empty. I ordered the housing and a thermostat so we’ll see on Thursday when the parts come in.

 

Well, the system was definitely low on coolant then, which is probably your heat issue. If I recall correctly, the guys at the dealer said they were only able to find my leak with a pressure tester.

 

Where was the leak?
Was it the thermostat?

nice to see another Ohio member.

 

yes hidden menu works the same on r50’s. At least on this 2006 r50...

 

I never found it so I’m just gonna take a stab in the dark and change the housing and the thermostat, it’s in the 20’s with snow and ice on the ground and I don’t have a garage so I haven’t really been able to dig into it like I’d like to.

Yeah I’m up here at the “walleye capital of the world!”

 

Just an update, I got the housing and the thermostat and changed them today (mid snowstorm in the driveway), I took out the top bleeder screw and kept pouring antifreeze in the fill cap until the bubbles stopped coming out of the bleeder. Started her up and ran it til it got hot with the heat and the fan on high, opened each bleeder screw to verify no air in the system, then went for a drive and now I’ve got heat in the car! Cooling fan comes on when it’s supposed to and then shuts back off. I didn’t notice any cracks in the housing I took off but there was corrosion on the head behind it and around the thermostat gasket. There was also a metal cap on the filler tube, whereas the new one has a plastic one.

 

Well, hopefully between the new housing, gasket, cap, and thermostat, it'll fix the leak. Fingers crossed.