Re: E34 tepid heater?

["Ron Buchalski" <rbuchals@xxxxxxxxxxx>]

I am just completing a cooling system service on my E34 525iT, and among 
other things, I replaced the hoses.  ALL hoses.  That includes the large 
upper and lower radiator hoses, the 'hydra' hose (connects to radiator, 
engine block, heater core, and throttle body), and all heater hoses.

Since this car has a dual heater control (driver & passenger), there are two 
coolant feeds to the heater core.  In order to independently adjust these 
heater temps, a pump (mounted above the ABS pump) manages the water flow to 
the two heater core inputs.

One of the replacement heater hoses (goes from the heater pump to the heater 
core) was much more expensive than the nearly identical hose right next to 
it, also connecting the heater pump to the heater core.  The difference?  It 
has a bleeder screw/valve included with it.  My original hose did not have 
this.

So, since it's at the highest point in the cooling system (higher than the 
bleeder screw on the radiator), it's in a great place to bleed air out of 
the system, and especially from the maze of hoses serving the heater core.

If your car is equipped with the dual heater controls, perhaps you should 
replace the hose with the bleeder hose, and it'll allow you to bleed all of 
the air from the heater core.

Ron Buchalski
BMWCCA #76387
1995 E36 M3
1993 E34 525iT
1999 Mazda Miata

>
>Date: Wed, 30 Oct 2002 04:02:27 -0500
>From: NOTES_TP.GREATLAKES.ggrigg <ggrigg@domain.elided>
>Subject: E34 tepid heater?
>
>Its a 518 Euro touring with 218K on the clock.
>The thermostat has been changed an the water temp is fine now.
>I only get tepid heat from the heater.
>Is there a quick way the check the little valves on the bulkhead and the 
>flaps
>are
>opening OK?
>Any tips on bleeding and access to the matrix.
>I don't have this trouble with the other one or my BMW motorcycle!
>Thanks
>GarryG
>NW UK
>g.grigg@domain.elided


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