[DML] Re: Cooling System Problems - still

["Joe LoRe" <dmcjoe@xxxxxxx>]

>From the description of Woody's original problem it appears to be 
related to air bubbles trapped at the thermostat. There is a simple 
test to determine if trapped air is the problem.

Do the following start the car and allow it to run at idle speed 
until the temperature reaches approximately 210 degrees. That would 
place the temperature gauge needle just below the 220 mark. At that 
point gun the engine eight to ten times. While the engine continues 
to run at idle speed observe the temperature gauge needle. If the 
temperature rapidly drops the problem is caused by trapped air at the 
thermostat.

I wrote an article on this subject several years ago when I marketed 
the "Overheat Protector". 

Here is part of what I wrote: 

"The location of the DeLorean thermostat creates a situation that 
causes air in the coolant lines to collect at the thermostat. This 
condition keeps the thermostat closed preventing coolant from 
circulating through the radiator. Because the coolant remains cool at 
the otterstat the cooling fans will not turn on. If this condition is 
unchecked the engine temperature will rise resulting in an overheat 
condition. 

Before the DeLorean went into production this problem became evident 
during test trials. The result was the installation of an air bleed 
screw at the top of the thermostat housing. Unfortunately "how to" 
information for cooling system bleeding procedures was not included 
in either the owners manual or workshop manual. After continuous 
reports from dealers and service personal the factory issued Service 
Bulletin ST-09-10/82 issued 10/18/82. The procedure is a four step 
somewhat complex process and is somewhat lacks certain details that 
make it difficult to achieve satisfactory results.

Back in 1986 I realized that many DeLorean owners were experiencing 
this problem. This situation combined with the well known cooling fan 
electrical problems was putting engines at risk due to overheating. I 
decided to research the condition to see if I could find a permanent 
fix for the problem. Over the years many people have commented to me 
that I had created a great invention when I developed the "Overheat 
Protector". In reality it was pretty easy to figure out. The cooling 
system was already designed with an air bleed hose for the radiator 
and one for the heater core. What was missing was an air bleed hose 
for the thermostat. I began my research by simply adding a short 
length of hose with two brass fittings that would allow trapped air 
at the thermostat to be expelled back to the coolant bottle where the 
heater core air bleed hose is located. I installed a prototyped on my 
DeLorean and several of my clients DeLorean's. It was not long before 
I realized that this modification completely eliminated the trapped 
air problem. As a side benefit it completely eliminated the need 
to "air bleed" the cooling system for the life of the car."

When I closed my DeLorean business John Hervey at 
www.specialtauto.com requested selling the "Overheat Protector" at 
his on-line store. You can find it as the "self bleeder" on his 
coolant system page. 

DMC Joe









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