Auto Service World
Feature   November 2, 2020   by Allan Janssen

How toxic coolant kills engines

Depleted, dirty, contaminated or intermixed coolant causes a wide array of cooling system issues, like this water pump damaged by a lack of inhibitors in the coolant and an over-abundance of particulate matter.

By Allan Janssen

Should a vehicle’s coolant reservoir be under lock and key? Bobby Bassett says there’s an argument to be made for such an extreme measure.

Bassett, the North American national training manager for Gates Automotive Aftermarket, told participants on a recent technical webinar that there’s a common denominator in many cooling system failures: contaminated coolant.

Water pump failures, radiator failures, and hose failures can often be traced back to depleted, dirty, or intermixed coolant, he told technicians and parts people on the call.

“These parts didn’t have to fail. They were forced to fail,” he said. “The only thing that will fix the underlying problems is a full flush at the time of repair, with system filled with the correct coolant for that vehicle.”

Jobbers can help by stressing to their shop and DIY customers the importance of using the correct coolant, and never mixing conflicting types.

“When a person has a cooling system emergency on the road, they’re likely to go to a parts store and buy some coolant and put it in,” Bassett said. “The question is what did he put into the system. That’s a very important question.”

There are four types of antifreeze, he said. “And they do not play well together!”

  • IAT (inorganic additive technology);
  • OAT (organic acid technology);
  • HOAT (hybrid organic acid technology);
  • P-HOAT (phosphated hybrid organic acid technology).

“If you look at the inhibitors used by these coolants, they all have different characteristics. There’s a reason they don’t mix,” he said.

“What will you say when the customer comes in and says, ‘I didn’t have the correct coolant, so I just put tap water in?’ Red flags should be going up! You have to say, ‘Well, because you did that, you have contaminated the system and we have to flush it out and replace the coolant when we complete our repairs.’”

He said offering a warranty on cooling system repairs is only reasonable if it includes a system flush.

“There’s no way for you to know if the coolant has ever been intermixed. You can’t verify what the last guy did. So the only way you can offer a warranty is if you do a flush,” he said.

The webinar, organized by the National Institute for Automotive Service Excellence (ASE), focused on the root causes of cooling system component failures.

Bassett said aftermarket studies have found that 40% of radiators received back for warranty failed due to coolant condition. Furthermore, 91% of OE coolant hose failures and 95% of water pump failures were found to be the result of missed flushes or the condition of the coolant.

Gates has been studying water pump failures since it got into the game and it developed the Be System Smart campaign to help educate technicians about the interconnectedness of the cooling system and its impact on other vehicle systems.

‘We should not be afraid
to ask the customer
if they want us to repair
the vehicle properly.
It’s a yes or no question.’

Showing a slide of a severely corroded radiator, he said, “When you pull a radiator that looks like this, tell the customer you need to flush this system. If you see some specific failure indications, you have to tell your customer that they have more contaminated coolant left in the block and you have to flush it out.”

Despite the importance of cooling system flushes, they often go unsold, Bassett said.

“If I teach 100 technicians over the course of a day, the one question I will ask is how many have a flush machine. Out of those 100 people, representing 50 to 60 shops, I might get 10 hands raised. The follow up question is, ‘How many of you actually use it?’ and almost all of the hands go down.”

This is often because customers are very price sensitive and may have called around to find out what a component replacement will cost. Shops are afraid of losing a sale if they have to add in the cost of a flush.

“The problem is the customer doesn’t know the difference between a job quoted with a coolant flush and without, so they will always choose the cheaper rate,” said Bassett. “But we should not be afraid to ask the customer if they want us to repair the vehicle properly. It’s a yes or no question.”

In fact, flushing the system will likely save the customer – and the shop – money in the long run.

A system with contaminated coolant still sloshing around in the block will immediately start to degrade sensitive cooling parts, corrode metals, and attack hoses.

“It’s time for us to help our customers understand what causes these failures,” he said. “When you’re doing a coolant replacement or a cooling system repair, don’t take the band-aid approach. When you take the band -aid approach you’re setting the customer up for failure even before they leave the shop. They will be coming back.”

Bassett believes that what’s really driving the problem is a lack of knowledge about changes to the cooling system over the years and a basic mishandling of coolant.

“Too many of us are sticking with repair practices from 30 years ago. So much has changed since then!” he said.

Gone are the brass, tiny, iron and lead radiators of the earliest days of the automobile.

“Today most of the coolant system is made with aluminum. Unfortunately, some of us haven’t changed our repair practices, and it’s causing failures.”

He said the only acceptable procedure for ensuring clean coolant is coursing through the system after a component replacement is with a flush and fill.

“The water-hose rinse procedure, where you drain the coolant make the repairs and then flush the system with a garden hose before adding new coolant will not work. The system will be re-contaminated once the engine is restarted.”

Draining and immediately refilling a system is the least acceptable approach. The engine block can hold 15 to 30% of the old coolant, which will contaminate the new coolant.

“If you have a flush machine, please get it out and use it. If you don’t have a flush machine, well there are a variety out there. I’ll leave it up to you to decide which one you want to buy, but buy one!” he said.

“The more you learn about the cooling system, the more you begin to wonder if the coolant system really should be under lock and key,” he said.