[DML] Re: overheating

["content22207" <brobertson@xxxxxxxxxxxx>]

What most people call the "overflow" tank on a DeLo is actually an
"expansion" tank -- it is located on the pressurized side of the cap.
Sounds like your PO rigged up a secondary true overflow bottle. Note
that this bottle is useless without a different style cap (won't be
able to suck the coolant back through). Stock DeLo simply spits excess
coolant onto the pavement.

Re: cooling fans -- the otterstat does not energize the fans directly.
It sends a trigger signal to Relay #24, which then routes fan current
through a circuit breaker and the imfamous "fan fail module", before
going to the fans. After the fans the circuit is grounded to the frame.

Diagnose in that order -- with the car energized:
- Check for voltage after Fuse #5 (otterstat)
- Jump the otterstat. The fans should come on immediately. If they
don't, check for voltage to the otterstat. While you're down there
ensure the otterstat is mounted upside down. Apparently on some cars
that coolant pipe is rotated with the otterstat on top, which
reportedly allows an air bubble to get trapped underneath.
- If the otterstat has voltage but fans still don't spin, check for
voltage at Relay #24 (row closest to passenger seat, 2nd from
outside). Terminal closest to the seat is the big power line in.
Terminal closest to outside of the car is the trigger line in. If
these lines have voltage, run a single jumper from the power line to
the terminal closest to the rear of the car. Fans should come on
immediately (if the otterstat is still jumped).
- The cooling fans are protected by a circuit breaker located between
the relay banks and the fuse block (the other is for the blower
motor). You can either jump this breaker BRIEFLY to see if the fans
will spin, or simply unplug the blower motor leads and use that
breaker to test.
- Adjacent to Relay #24, closest to the outside, is the imfamous "fan
fail module". The original is blue in color. If you still have it,
that may well be your problem. The traditional fix is simply to
replace the module with a 3 way jumper. This fix generates a lot of
controversy, but you'll notice that DMC itself recommended doing the same!
http://www.dmcnews.com/bulletins/ST-06-9.82.html
- After the fan fail socket, the circuit splits into two lines, one
for each fan. At least one fan should now be spinning (all other
jumpers still in place). If you've got voltage to a dead fan's outside
terminal of the fan fail socket (rotated 90 degrees from the line in),
check for voltage at the fan itself, especially on the ground side.
The fans are grounded to the crumple tube, exposed to the worst road
elements. 

Bill Robertson
#5939

>--- In dmcnews@xxxxxxxxxxxxxxx, "funkstuf" <funkstuf@xxxx> wrote:
> Hi Group.
> Couple questions about this overheating business.
> My car has several items on it including the air bleeder hose fix.
> In addition, I've noticed that it doesn't have a stock antifreeze 
> tank, though it appears quite similar, and strangely, it has a 
> secondary antifreeze tank.  That is, the overflow hose from the 
> antifreeze tank goes to a second smaller antifreeze tank on the left 
> side of the trunk.  that second one then has a vented hose.
> apparentely someone had their own idea of how to solve the over 
> heating problem.
> Anyway,  The other day I drove the Delorean, then let it sit and run 
> a bit.  the car first heated to the middle (220, still in the white)
> previously the fans would kick on around this point.. No fans...and 
> engine continued to heat to the point it was going to overheat and 
> still NO FANS.. so.. I LET IT GET COMPLETELY COLD.  Then, as per the 
> advice of Mr. Hervey, I took the cap off of the antifreeze tank and 
> started the car and let it run for awhile.. I could see the 
> antifreeze circulating.  I then drove the car a bit and let it sit 
> and it begin heating up..
> It then heated up to 220 (Right in the middle) and when it went above 
> this, the fans kicked on and cooled it down to just below that center 
> point..  so what gives?  I thought if it had air the airbleeder hose 
> would bleed the air?  Any ideas besides air.. and also, is it normal 
> that fans should kick on right when it goes above the center line?
> If not, where should they turn on?
> No, I do not see any antifreeze in the exhaust, plus, I've got new 
> head gaskets and the oil appears very clean so I don't suspect a leak 
> there.
> 
> Thanks
> Dale Funk
> #4984



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