Engine Air Pocket and overheating

[rich]

Does anyone have information on overheating problems and air pockets in the cooling system of thier roadster. I have had 2 water pumps put in, a new radiator, and 3 thermostats. The system has been bleed many times, and over time the air pocket appears again and the car runs hot until it overheats. Then comes the tow truck.

Help please.

 

[grc]

i'd say check the seals on the bleeder and the radiator cap, could be a loose clamp or corroded hose connection, or even a bad radiator allowing air into the system as the the car and cooling sysytem cools down. as it cools down it tries to suck the coolant from the overflow back into the radiator. sounds like it's getting air from somewhere. instead of the tow truck, carry a gal of premix and a tool to open the bleeder. you'll have to let it cool down before you open it up, but it'll be cheaper until you find the problem.

 

[rich]

Thank you for your reply. Sounds like your coming from experience or a strong automotive repair background. When the problem started I would pull over and bleed the air out and refill the overflow, but eventually the car hits the redline and I can't continue on. I actually had a policeman pull up and threaten to ticket me for having leeked radiator fluid. I had the car pressure tested and they can't find any leeks. Do they pressure test through the cap opening, that could explain why it tests good. After I let the car sit and cool down the overflow tank reads full. That's what confuses me. Thier was a recall on the rediator cap. Bmw says that it has been replaced. I agree with everything you suggested, but how do you get the airpocket out if the problem is fixed, say by replacing the cap. I appreciate your input.

Thanks again.

 

[grc]

mom's 87 caprice wouldn't hold pressure and very slowly lost coolant, but yet had no leak. after doing a bunch of work that required disconnecting a bunch of hoses, the system held pressure afterwards. i learned about bleeding the BMW radiator during the install of my supercharger. i didn't get a block away before the needle was in the red. there might be another bleeder that you aren't aware of, have you looked in a manual ? aren't cars fun!

 

[muskyman]

bleeding the system is key on BMW's

on my 750 you need to park it nose down a steep hill because the over flow bottle is located behind the engine high on the center of the firewall.

once you learn this trick it will self bleed in no time then cap it up and away you go.

without this trick a sloppy simple fill of the system will trap air and cause almost instantanious over heating

MM

 

[grc]

where you at Muskyman? we're runnin circles around each other!

 

[Audible]

My temp gauge stays right at 1/2 all day no matter what the outside air temp... I would talk to your dealer or call BMW directly. I'm sure you not the only guy with this problem.

Hope this helps.

Audible

 

[muskyman]

grc

Barrington...and you?

MM

 

[grc]

i'm in naperville, i get up through barrington on wed'sdays sometimes. over by 12@22. do you have a personalized plate on one of your vehicles? i think i remember seeing a musky-something plate?