Module One, “What’s Hot in Cooling”

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Module One, “What’s Hot in Cooling”

Schaeffler Tea Break Sessions January 12-13 2021


Module 2:

Switchable PumpsModule 3:

ThermalManagementUnits

Module 1:

What's Hot

Introduction


Seal technology design changes…Why?

In the past Aluminium Oxide (AlO) seals were used without major problems.

So why not today?

• In the past most engines were made of cast iron= Abrasive material in the coolant was rust

• Today: Either the cylinder head, or the complete engine is made from Aluminium= Abrasive material in the coolant is aluminium oxide > much harder than rust!

• Therefore: If you have Aluminium Oxide deposits in the coolant they will not be removed,because the seal is made of the same material!


Sliding ringHarder material than Stationary ring

Stationary ring

Sealing surface

Best performing seal material combination:

• Hard Carbon (HC) for the Stationary ring (softer material)• Silicon Carbide (SiC) for the Sliding ring (harder material)• 99% of our pumps use this combination

You get what you pay for!

Seal technology : Many aftermarket pumps still use Aluminium Oxide seals (AIO)


New mechanical seal before first run:• Minor rough surface• Requires bedding inFirst running:• Partly high pressure• Partly dry running• Seat grindingAfter some hours of running:• Smooth surface• Waviness, less than 0.1 µm

Hydrodynamic lubrication approx 0.1 µm

Mechanical seal: First seat grinding / Stationary ring

That’s 1 x Micron (1000th of a millimetre) – a human hair is 50 Microns!

NOTE: All water pumps leak initially on start up

Evaporation chamber


Plastic• light• flow efficient• high quantities needed• medium risk of fracture

Cast iron or aluminium• heavy = higher risk of unbalance• medium risk of fracture

Sheet metal (steel)• light• less flow efficient• low risk of fracture

Market Trend

Different Impeller Designs


Ball / Ball

NOTE:The same load handling capabilities can be achieved by both designs, but the Roller/Ball design is more compact

Roller / Ball

Different Bearing Designs


Requirements:

• Operate in a wide range oftemperatures

• Low freezing point

• High Boiling point

• High Heat Capacity

• Protect Against Corrosion

• Lubricate Water Pump

Cooling system Specs:

• Coolant system is designedto run at around 90°c

• 50/50 mixture, raisesboiling point and reducesfreezing temperature.

• System is pressurised toapprox. 15psi, raisingboiling point further

Coolant


Hybrid of IAT & OAT Strong Anti-corrosive

Considered longer life coolant

Protection for Aluminiumand Magnesium

Eliminates need foradditional additives

Considered longer life coolant

Strongly Anti-corrosiveTypically used in older vehicles

Requires regular changes

IATInorganic Additive

Technology

OATOrganic Additive

Technology

HOATHybrid Organic Additive

Technology

What about the colours?There is no universal colour system for coolant,so its always advisable to check the VM specs

Coolant Types


Coolants do not mix!Corrosion inhibitors and additives from one coolant,can negatively effectanother if mixed

Do you know the fullhistory of the coolant system?Has the owner topped it upthemselves?

Coolant lasts foreverdoesn’t it?Cooling aspect does not degrade, the corrosion inhibitors do.

Coolant : Mixing / Changing / Selecting

NOTHING LASTSFOREVER

NOT EVEN COVID!

For example, Silicate protects aluminium while Borate corrodes it.Corrosion can begin <5K miles into a water pump’s life, causing leakage and the car coming back to your workshop!


Product selection would be easy if every manufacturer developed their enginesand cooling systems in the same way with the same materials…. But they don’t!

A typical change interval on coolant is 5yrs or 30,000 miles - with some manufacturers recommending as low as 2 yrs / 30,000 miles

We would always advise following the vehicle manufacturer’s recommended change interval and product selection

Coolant : How to choose

How to get it right:

• Manufacturer’s online look up

• Speak to the factor (don’t just give a reg nr and hope)

• Take note of manufacturer approvals and specifications

• Check with the main dealer.


Checking coolant strength

A refractometer measures:• Ethylene glycol & Propylene glycol• Screen wash additive• AdBlue• Battery acid• Available on Amazon for £25.00

Tools


Leak / pressure testing• Coolant stains indicate leak• Pressure testers help locate coolant leaks

and ensure a professional quality repair

Tools


Leak / pressure testing

Internal leaks• Cylinder head

- Pressure test over night- Check at the exhaust for coolant steamor white smoke

• EGR cooler leaks- White smoke- open EGR system- look for damp / gumming up / black carbon

Tools


Vacuum filling

• Ignition on & heater on hot• Put a vacuum on the system – check it holds vacuum

(confirms no leaks)• Filling – not introducing air pockets• Coolant around pump for initial start up,

can introduce more vacuum if required when filling• Quicker• Reduces the risk of a return to workshop

Tools


• Run up to operating temperature• Drain coolant• Clear affected components – back flow• Refill with flush / detergent• Run engine for 90 minutes• Drain the flush / detergent• Refill system with neutraliser• Run for 15 minutes• Drain neutralising fluid• Refill system with correct coolant• Run for 10 minutes• Drain coolant• Replace blocked/contaminated components• Replace reservoir if required• Refill system with correct coolant & mixture

NOTE: Replace all blocked/contaminated components after flush

Flushing Process


Fact: Leakage accounts for over 85% of failures!

Failure Analysis / Diagnosis


Bearing Damage… usually a bi-product of seal failure?A leaking seal can allow coolant to wash away the grease in the bearing, causing it to fail with catastrophic results



What are the two biggest causes of premature failure ?Coolant impurities and excessive sealant deposited in the pump seal…

Remember the One Micron (0.1 µm) seal gap?



To seal or not to seal, that is the question!

Sealing

REINZOSIL ELRING DIRKO

LOCTITE Si5699 PERMATEX 22071

SUMMARY• RUBBER O RINGS: NO Sealant (coolant smear only)• PAPER GASKET: Officially NO Sealant (hold gasket in place)• METAL: NO Sealant• NITRILE COATED METAL: NO Sealant (coolant smear only)• NO GASKET: Use ‘Form in place’ gasket solution

BUT NOT in formed channel


For pumps requiring a “Form in place gasket” solution…Apply sealer to the outside of the channel 2.25 to 2.5mm bead - Do NOT allow sealant to enter the channel!

What can go wrong


VAG – Poor heating

• Loose water pump impeller: remove small return hose onexpansion tank, engine running 2500 rpm, should havegood return flow, if poor investigate water pump

• Silica bags split in expansion tank, remove expansion tank,remove Silica bag & inspect - if split flush system andreplace matrix if required

• Sand in engine block from casting, indicated in expansion tank

• Similar issues occur in Mitsubishis: flush as required

What can go wrong


Coolant issues

What can go wrong

RUSTIncorrect coolant mix ratio

CAVITATIONCaused by air pockets in

coolant – system not bled correctly

CALCIFICATIONWrong coolant dilution

CONTAMINATIONMixed incompatible coolants


INA Cooling Product Options

NOTE: Check with your supplier to find out the product warranty they offer

Documents

Module One, “What’s Hot in Cooling”