Freezing cold overheat.E3 content

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Buffarea

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Grand Rapids, Mi.
Unfortunatly the Bavaria is being used 5 days a week and it's cold and wet. Fortunatly I do have a garage for it.
Last week I started it cold and left it to warm up, it was about 11:00 at night snowing and freezing and I had 40 miles to get home. It ran about 10 minutes and I came out because the high idle should have dropped by now and found it with steem coming from every corner of the hood. The temp gauge was at 2/3s and the thermo/electric radiator fan was running. I let sit to cool about 1/2 hour and could not tell where the coolant had come from except the bottom of the radiator was wet. Mind you there is a foot of snow on the ground and blowing. Assuming it was the radiator I removed it and brought it to a local shop who could not find a problem with it. But they put a nice fresh black paint on it for $20.00. I picked up a t-stat and installed them both with new coolant mix.
I have driven it the past 4 days and have had to add coolant twice, the temp gauge reads warmer than it used to, and occassionally the heater will suddenly blow cold, eventually warming back up. I have noticed a little more smoke on shifts recently as well.
Otherwise it is amazingly fun to drive with 4 snow tires and 40lbs of dogfood in the trunk.
Any tips appreciated.
Michael
 
Is coolant coming out of the exhaust pipe in the form of steam/dripping? Could be head gasket issue if no other leaks found.
 
You also might have to properly bleed the system. That´s tricky on the M30 (as I´m sure most here will know), espiecially in winter when the thermo probalby never fully opens.
Doesn´t explain the first symptoms (overheating, voolant on the floor) though. May really be a blown gasket or even a cracked head. Original engine/head or later?
 
"the temp gauge reads warmer than it used to, and occassionally the heater will suddenly blow cold, eventually warming back up."

These are symtoms of air.... bleed..

Double check all the small hoses... even a drip can overnight be a problem.

My only other tip would be to make sure that you clocked the t-stat ( oriented it ) or drilled a bleed hole at the top.

On the high idle longer than normal; you have have reached a temp low enough for the thermo valve to work ( small rectagular box wired to the solenoids). It's really just another choke device that opens up a fuel circiut past the secondary butterfly which only works when extremely cold. I was alarmed the first time I realized what it was and not linkage just hung up.
 
There does not appear to be liquid coming from the tail pipe, and the smoke on shifts goes away as it warms up. No doubt there is also a little oil burning when cold.
There has been a drip hanging from the overflow hose on the resevoir next to the cap, but I have'nt actually seen it drip-if that makes sense. Just curious that it is wet often. I can see flow from the waterpump aswell into the plastic tank.
I have a food thermometer in the defrost vent so I can watch the output temp., but on my last 1/2 hour run it was stable at about 100* heat.
I am going to bleed it again tomorrow after it has had a chance to warm up.
 
Start your car and remove the small hose going to the expansion tank- Verify water is squirting out of that hose with volume dependent on rpm.
If that hose or either nipple is blocked you will overheat again
 
I have been driving the car as much as 100 miles daily. The temps have been between 0 and 20 out. The engine runs slightly warmer (per gauge)but it may be wonky since the steam over and heat output is not hot. Vent thermometer says heater output is 100 to 110. I do have cooling system pressure at res.cap, but t-stat housing and top of radiator never get real warm. I am not losing coolant as far as I can tell.
I have tried to bleed system twice more but no air.
Comments are welcomed.
 
T-stat temp

Buff,

What temp is the stat? Maybe on the reciept or box. I think standard is 80. A little higher temp on the guage than before could just mean the stat works better than the old one, but clean the terminal on the temp sender.

I'll try my heater discharge temp and report back. It does get hot hot at least by the shoe method.
 
Temp on heater

Buff,

40 degree outside air, I get 120 degrees with t-stat probe inside of drivers floor outlet. Engine warmed up 5 minutes past choke kickdown, temp guage roughly 4 o'clock. Full fan, full hot. Engine t-stat housing is hot. Some heat off the top of the radiator.
 
six other things to check

As noted above, it's vaguely possible you have a head gasket, or that corrosion has connected a combustion chamber with one of the water passages. I got an '02 once that had connections on three out of four combustion chambers on the head. It still ran, but you couldn't see the ground through all the steam coming out the tailpipe.

When you've got time, you can pull the plugs and see if they're all evenly colored. If one cylinder is letting water in, that spark plug will be very clean. So will that cylinder once you take off the head.

But this scenario is among the more unlikely.
 
61porsche said:
Buff,

40 degree outside air, I get 120 degrees with t-stat probe inside of drivers floor outlet. Engine warmed up 5 minutes past choke kickdown, temp guage roughly 4 o'clock. Full fan, full hot. Engine t-stat housing is hot. Some heat off the top of the radiator.
Click to expand...

Thanks, that gives me a standard of measurement. I checked per your suggestion (61Porsche) and the Tstat I removed was 180*, the new one is a 192* so there is a significant difference. I failed to mention that a few days after you suggested the resevoir cap I did replace it too.

I had been checking heat output at the defroster vent, but upon reading your last post tried the floor vent, and it is almost 120*.
In the summer I had the carpets and seats out, and the trim panels around the seat belts and found no real problems, but now think I have either many small air leaks into or out of the car making it not really warm up well, it's the only thing I can come up with. ( It is warmer at lower speeds)
Hopefully this car will be taken off the road soon for the planned resto., and a head rebuild and gasket will be among the growing list.

Thanks for the comments, I hope this helps someone else as it as helped me.
Michael
 
I found that my insulation at the shifter was askew and that the door panels ( holes for accessing the window motor gear) were a source of air infiltration.

I thought you might try taping temporarily something ( carboard to start) on one side of the heater blower ( engine compartment) since it gets air on both sides. The theory being with very cold air outside, you might slow the inflow amount down enough to give you another 10 degrees. Kinda like a shroud for the radiator but for the heater coil whereby the airflow is directed to about 75% of the surface area.

Worth a shot- I remember how cold can be- once drove a Fiat w/ no heater ( girlfriend's car) from Atlanta to SC in zero degrees. Coldest I've ever been; including Chicago on Lake Av. Dr.
 
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