MACS Monthly Newsletter - 2017 - MAY3

on a cooling system issue and wonder to yourself,"could
it be the coolant / water I'm using?"

the engine. Sometimes the PCM doesn't know if the variable displacement turbo is faulty due to a change in back
pressure caused by a faulty EGR system so it flags the
turbo with a DTC. Many techs opt for the thorough method of replacing both heat exchangers (oil and EGR) along
with a complete flush and refill with Ford approved premix or antifreeze and distilled water. There are improved

Courtesy US Geological Survey

Unless your shop is located in the middle of the Sahara Desert, chances are acquiring water for mixing with
coolant is not a problem. If you opt for premix the topic
is a moot point so long as the premix coolant provider
uses water the OEM recommends. What do you mix with
your bulk antifreeze? Well water, City/Municipal, Distilled or Deionized Water? (Fig. 2)

Figure 2: A similar map was published in a MACS Service Report during the
height of the GM Dex-Cool related contamination dilemma. Now we turn
our concern to the water added to antifreeze that cools high voltage battery
packs and power electronics. The mineral content (hardness) of water from
wells varies by region. The darker the shade of grey, the worse your well
water is. Municipal water supplies are often better but not always. This author's city water in Kokomo, IN suffered from deposits that clogged the screen
of every sink and bath fixture in his home a few years back. The latest news
on municipal water supplies comes from Flint, Michigan where the water's
lead content will remain undrinkable for many years until the problem is
fixed. The question is, do you want that in your customers' cooling systems?

Distilled is Good!

May 2017

Drawings Courtesy Ford Motor Company

A good vehicle application example where you will
want to dot every 'I' and cross every 'T' regarding antifreeze and water choices is the Ford 6.0 Powerstroke.
If you've not been making money working on the Ford
6.0 Powerstroke, you probably just don't do diesels. The
engine has more than its fair share of service opportunities for the shop that is willing to learn this engine's
quirks. Soot from diesel combustion can restrict the exhaust flow inside the EGR cooler. (Fig. 3) Coolant can
become corrosive from lack of maintenance or mineral
/ sediment rich tap water usage. Casting sand that can
restrict coolant flow through the oil cooler (Fig 4) often
starts the avalanche of complications. The higher coolant
temperature then causes the EGR cooler's coolant to begin making bubbles which then in turn causes the cavitation that creates the EGR cooler leak. Next comes the
bubbles in the surge tank along with white smoke out
the tail pipe. Both of those symptoms mimic a bad head
gasket. EGR systems on the 6.0 are monitored for proper
flow via 'virtual sensors' on most model year variants of

Figure 3 and 4: Coolant Complications: Ford Powerstroke cooling systems
can be tricky. Ford's Powerstroke 6.0 Diesel uses engine coolant to cool
the block, the cylinder heads, engine oil and EGR. The complexities and
interactions with coolant temps running in either of these heat exchangers
can create restrictions and leaks that will result in vehicle symptoms ranging from a faulty head gasket (white smoke and bubbles in the degas tank)
or even false turbo DTCs.

MACS Service Reports

Table of Contents for the Digital Edition of MACS Monthly Newsletter - 2017