Coolant not circulating 318i m43 - E46Fanatics E46 BMW Social Directory E46 FAQ 3-Series Discussion Forums BMW Photo Gallery BMW 3-Series Technical Information E46 Fanatics - The Ultimate BMW Resource BMW Vendors General E46 Forum The Tire Rack's Tire Wheel Forum Forced Induction Forum The Off-Topic The E46 BMW Showroom For Sale, For Trade or Wanting to Buy

Go Back   E46Fanatics > Tuning & Tech > DIY: Do It Yourself

DIY: Do It Yourself
Post here to share or improve your wrench turning skills! All BMW E46 DIY tips, tales, and projects discussed inside. Learn to work on your car and know the right BMW parts you will need!

Thread Tools Search this Thread Rate Thread Display Modes
Old 09-28-2019, 12:27 PM   #1
Registered User
Join Date: Sep 2019
Location: Australia
Posts: 4
My Ride: 318
Coolant not circulating 318i m43

Been trying to rectify the cooling system and I'm stumped. A side issue: The temp gauge is pegged high at all times probably due to it's sensor which is somewhat inaccessible and not my current focus. Cluster test shows the gauge is ok. It's a 2000 M43 (1.9L 4cyl) 318i auto.

Symptoms: Top radiator hose gets way hot, bottom hose remaining relatively cool and pressure builds up in the system. Hoses will be solid after a 10 min drive. I had thought it may be a head gasket leak, but there's no combustion leak to coolant causing the pressure build. No oil in water and no water in oil. No white smoke from exhaust. Seems the pressure build up is due to no movement and coolant boiling.

I replaced the water pump, suspecting that was the issue. Still no circulation. Removed the brand new thermostat and replaced it with just an old thermostat housing, so no thermostat is involved for the following testing.

Checked the coolant flow for blockages. Removed top and bottom radiator hoses. Used a garden hose into the top cap of expansion tank and there was easy flow through to bottom outlet of radiator. Ok, so no blockage there. Garden hose into thermostat housing, easy flow out to top and vice versa of garden hose into top hose and out the thermostat. When I pulled the pump out, I blocked off the thermostat housing and blew water into pump bore, and water flowed freely to the top hose and blowing water into the expansion tank, water came freely out the pump bore. Disconnected the top hose from the radiator and drove water directly into the radiator, the water came out the top hose.
I have filled and bled this system at least a dozen times during all of this. I've removed the new water pump to check it was ok and reinstalled it.
Am I missing something?
awayaway is offline   Reply With Quote

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Censor is ON

All times are GMT -5. The time now is 04:21 AM.

Powered by vBulletin® Version 3.8.8
Copyright ©2000 - 2020, vBulletin Solutions, Inc.
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2020 DragonByte Technologies Ltd.
(c) 1999 - VerticalScope Inc. All rights reserved.