Re: bmw-digest V9 #1814

[Tom Schmidt <gdearle@xxxxxxxxxxxx>]

Other E-24 owners I know complain of heating problems in California summers.
Here are some ideas --
Air flow through the radiator is due to pressure difference. Reducing the engine
compartment pressure promotes flow through the radiator if there are no other
"leaks"
into the compartment.  On my E-30, foam rubber strips at the front of the hood
(top of the grill) close this gap and plastic panels behind the headlights block
flow through the grill.

Air dams reduce pressure under the car including the engine compartment. The
smaller the gap between the air dam and the road the bigger the effect (in
addition to making it easier to damage the air damn against curbs).  One air dam I
had reduced the gap with a 2" wide strip of stiff rubber along the bottom edge.

A "belly pan" underneath the engine compartment (if the E-24 has one?) will reduce
flow through the compartment - that is raise the pressure.  Some cars have a pans
that cover only the front of the compartment (between the radiator and the engine
block) to improve flow through the radiator.

Removing the seals at the back of the hood may lower compartment pressure but it
creates a potential safety hazard - oil, smoke, coolant, or whatever from the
engine (perish the thought) can flow onto the windshield.

Locking the fan clutch will increase loads on the water pump bearing.  I don't
know if this will have a significant effect on bearing life. You may be the first
to find out.
Does your E24 have a shroud around the fan? Shrouds improve the effectiveness of
the fan
by redirecting radial flow of air off of the tips of the fan blades.
Metric Mechanic offers high volume water pumps for the big six.  They also have
"Cool Down Pulleys" - smaller pump pulleys which increase pump RPM.
http://www.metricmechanic.com/

my 02 cents worth

Tom Schmidt


> Date: Sun, 27 May 2001 13:41:31 EDT
> From: Dogkip@domain.elided
> Subject: E24 Fan Clutch
>
> I live in Dallas, TX and continually fight the "running hot" problem.
> Problem only surfaces when in heavy traffic on a hot day. I have tried most
> everything... flushed system, new radiator, cleaned outside fin surface on
> condensing coil, auxillary fan bypass, wetting solution, removed center core
> of the thermostat.  My latest change was to run a couple of screws through
> the fan clutch to prevent slippage.  I noticed that even at low speeds, there
> was significant slippage, reducing air flow through the radiator.  Locking
> the clutch significantly increased the fan tip speed.   I had tried a new
> clutch, but noticed that there still was slippage.   My question is ... will
> locking of the clutch cause any other problem?  I realize that it will suck
> off some hp, but that is a small price if I can keep the temperatures down.
>
> Also, any other things I can try? One of the biggest problems appears to be a
> very tight engine compartment and restrictive air flow through the engine
> compartment.  I was thinking of removing the rubber seal near the cowling
> just in front of the windshield to allow some of the air to blow out the
> louvers.  What kind of trouble can that get me into?
>
> Ray W.

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End of bmw-digest V9 #1816
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