Elijah
Elijah New Reader
Nov. 19, 2012 6:25 p.m.

hello GRM, I have a 90' 325is. I have had my bimmer for a couple months now, when I first bought it it had a weird problem, it would run hot (creep up to the 3/4) but only when i was idling or running at very low RPMs. i thought it was the fan clutch but after about a week and then it just completely stopped. so i left it alone. but recently i decided to check on the coolant when the engine was completely cool. as i unscrewed the overflow tank cap it slowly hissed for about a minute. now the same problem came back as before... why was there pressure in the cooling system when it was completely cool? did this pressure somehow fix the problem i was having with the idle? ALSO the coolant fan switch wires are messed up and possibly not making any connection. but it was like this the entire time ive had the car.

thanks for your help guys.

mad_machine MegaDork
Nov. 19, 2012 6:51 p.m.

might always be some residual pressure.. and the way a BMW cooling system is set up.. it keeps the coolant out of the reseviour. you most likely have an air pocket now. You will need to open up the bleed screw at the top of the radiator and top it off till coolant comes out.

It will leak some for a while afterwards.. and then calm down

stuart in mn PowerDork
Nov. 19, 2012 7:00 p.m.

Yes, it sounds like air in the system - with the engine off open the screw and add coolant until it runs out the bleeder. Tighten it up, start the car and get it up to operating temperature, then while running crack the bleeder screw again until the coolant coming out is free of air bubbles.

Elijah
Elijah New Reader
Nov. 19, 2012 9:11 p.m.

Thanks guys I'll try bleeding it tomorrow and let you know how it goes

You'll need to log in to post.

Also on Grassroots Motorsports

Reader's Ride of the Week: Enviate Hypercar

2 hours ago in News

There’s fast and there’s FAST–and then there’s this thing.

Join the Grassroots Motorsports Dyno Day

3 days ago in News

Join us for a dyno day in Sterling, Virginia.

From the GRM Vault: The Art of Understatement

4 days ago in Articles

The Harvey brothers dominated autocross in an obsolete Datsun a couple decades ago.

2017 Volkswagen Golf TSI SE

4 days ago in New Car Reviews

The quintessential European hatchback continues to pour out of Volkswagen's plants. Our test car featured four doors, a turbocharged 4-cylinder ...

We're Giving Away a $500 Race Ramps Certificate

5 days ago in News

Joining the drawing is totally free.

25 Project Path

5 days ago in Articles

A walk through 25 of our favorite project cars from the past.

Our Turbo Miata Goes Boom

6 days ago in Project Cars

Engine swap and suspension revamp before our race in two weeks? Challenge accepted.

The Ultimate Weekend Getaway for Your Car Club

1 week ago in News

Save a corral space just for your club at the Mitty.

Reader's Ride of the Week: V8 Jag

1 week ago in News

It’s a long-wheelbase 1974 Jaguar XJ6 fitted with a 350-cubic-inch Chevy V8.

Honing Cylinders

1 week ago in Project Cars

We hone our LS1's cylinders

Break Maiden

1 week ago in Articles

Creating a turbocharged road racing champion from a vintage Ford Mustang.

Meet Us at Sebring

1 week ago in News

We'll be at the Mobil 1 Twelve Hours of Sebring. Will you?

OUR SPONSORS

Birthdays

Grassroots Motorsports Magazine

Subscribe Today

Also get your instant access to the digital edition of Grassroots Motorsports Magazine!

Learn More
x0h1fjadypRzBaZCDWINdXE1LuiGMbXH