It started with a phone call. “I have a bad water pump on my ‘04 Acura MDX. Can you email me an estimate?” Acura’s MDX is their top tier crossover vehicle. With the confidence of all-wheel drive, a strong 3.5 liter V-6 and well appointed accessories, the MDX is a great ride. An estimate was emailed to the owner, Chris, for a replacement water pump along with the recommendation to replace the timing belt as well. In this vehicle, like many others, the water pump is driven by the timing belt. The timing belt has to be removed to replace the water pump. To replace the water pump, takes just over 5 hours. Why go back in, pay for 5 more hours of labor, 20k miles down the road? The cost of replacing the timing belt while replacing the water pump is just the price of the part! Little did we know there was so much more to the story and the devil was in the big $ repair! the ending is a shocker to the check book!
A short time later Chris called back and said the timing belt would be due for replacement next year so he wanted it replaced with the water pump. Chris dropped off the MDX and picked up one of our free loaner cars. Learn more… about our free loaner cars.
Once in the shop, Tony started in on replacing the water pump and timing belt. About 2 hours later he came in and asked “Why are we replacing the water pump?” “Chris told us he had it checked out and the pump was bad”, I replied. Tony went on to say that the water pump was not leaking and the pump’s impellers were fine.
I called Chris and told him our findings and expressed our concern; “What made you to think the water pump was bad?” He went on to tell us that a mechanic friend of his had checked it out and said the water pump wasn’t circulating correctly. This led to the next question, “Has the engine been overheating?” “Yes,” replied Chris.
Oh that Devil!
Most of today’s vehicles have aluminum cylinder heads which do not like to be overheated! It is the quickest way to warp the cylinder heads and cause a leaking head gasket. Worse yet are cracked cylinder heads! The Devil was smiling with delight.. The MDX had been overheated several times! Back in the shop Tony performed a chemical test on the cooling system. In the industry we have a chemical that responds to the presence of combustion gases. The liquid will turn from blue to yellow if combustion gases are detected. As you’ve already guessed, the test was positive. Chris received an updated estimate for replacement head gaskets with a warning that overheating an engine too many times can crack a cylinder head which can add additional dollars to the repair. The devil was laughing… We were starting to wonder… was there more we should know? Tony removed the timing belt, yes that has to be done to remove the cylinder heads, and apart came the top half of the engine.
Once the cylinder heads were removed it was found that the rear cylinder head gasket had failed and the front cylinder head gasket was on the way out. The cylinder heads were sent to a machine shop for inspection. After cleaning and pressure testing for cracks the good news was the heads were pretty much okay. No cracks were found and only resurfacing was needed to make them flat again. Once the heads returned, Tony was back at assembling the engine.
The Devil Laughs Again
Once together, the engine was started; it sounded great! As Tony started to top off the cooling system a strange thing happened. The engine started to overheat! Right there in the shop! The cooling system was pushing coolant out! “Must be an air pocket,” Tony thought. He let the engine cool down, restarted it and started to add coolant. Once again, the temperature gauge climbed and the engine started to overheat. It was easy to see, Tony was pretty irritated. Tony is retentive in a good way. You know when he is done, the job is done right. With the red showing in his face I knew there was hell to be paid, he wanted to prove he had done the job right. Out came the chemical test for the cooling system. The test came back negative for combustion gases.
So what was going on?
In our shop we have this little rule. If it’s not going right we put our minds together and ask;
“What do we know and what do we have to prove?”
- Is the thermostat working as it should?
- What is the condition of the radiator?
The radiator in this MDX is buried under plastic covers and shields. A closer inspection found a surprise! The radiator was new!
We have this cool little tool that reads the surface temperature of anything you point at. Squeeze the trigger and get an instant digital reading. As the temperature gauge climbed the radiator stayed cool, really cool while the engine was ready to boil. Yes! A bad thermostat! The housing for the thermostat was removed and the thermostat was pulled out.
The devil smiled again..
The thermostat was new!?? Okay this is getting maddening.. A new original equipment thermostat was ordered and installed. We’ve had problems with aftermarket thermostats from time to time. There was too much at risk at this point. The engine was started. The problem was still the same! Tony’s blood pressure is climbing faster than the MDX is overheating and I’ve gotten more gray hair! Like I need that!
For a short moment our vocabulary expanded. Once we calmed down we reviewed, once again, what we did know and what we needed to prove. At this point we knew we fixed a lot of broken things but not the root cause of the problem!
What we do know…
- Good Water pump
- Good head gaskets, we proved it.
- Good heads, tested and proved.
- Good radiator? Must be, after all it is new?..!
- Good thermostat, 2 defective? Not likely. Yet, I have seen it.
What we don’t know…
- Why the coolant is not going through the radiator?
The radiator must be plugged! We took out our borescope with a video camera. Tony drained the cooling system and removed the upper and lower radiator hose and in went the scope. (Once we found a shop rag in the tank of a radiator. That’s what we were looking for.) All Tony found was a small piece of silicone, which would not cause this problem. Silicone is a commonly used product for sealing gaskets or metal to metal components in today’s engines. He squeezed the coolant hoses to see if he could feel something in one of the hoses, no luck. Tony took his flash light and looked up the lower radiator hose. A short time later he came over to the service desk and said, “Jim take a look at this”. From the lower radiator hose, he had removed the root cause. Tony and I both knew just what the problem was and where that problem came from.
The mystery was solved!
The root cause for the misdiagnosis of the water pump, damage to the engine’s cylinder head gaskets, Tony’s high blood pressure, my gray hair and a $3,500 plus repair bill was found! Chris was working at the other end of the state when I sent him the picture of what we found. (In retrospect, that was about the right distance at the time.)
It’s all about the story, isn’t it?
With the twists and turns of this repair we knew there was more to the story. Chris told us that approximately 2 weeks before, his wife was driving home one evening with a MDX full of kids and the family dog, when coolant poured out from under the car. The MDX was towed to a nearby shop. She got a ride home from a friend. With a car full of kids, halfway home she realized that they had left the family dog in the MDX. The shop’s diagnosis was a failed radiator. A replacement was approved and installed. That is where the problem started. They had the MDX for a week and Chris found it odd that it was taking so long to get a radiator replaced. Once he picked up the MDX he found that the car would randomly overheat. That is when his mechanic friend diagnosed the water pump problem.
I knew what was next
I knew that Chris was going make a not so pretty phone call. I knew the next phone call I would receive would be from the shop that replaced the radiator. Sure enough, it wasn’t pretty. I got called a few things and was told it was fishy and, “I’m coming to see you”. After all, Chris wanted to be compensated for the damage and repairs that had been performed. Chris also warned me that this guy was very unprofessional.
Meet Mr. Unprofessional
When Mr. Unprofessional came into the office, I showed him what we had found. He loudly stated that replacement radiators don’t come with caps/plugs like that!
What Mr. Unprofessional didn’t know is, I had ordered another radiator, just to prove we were right. I politely walked him over to the box with the radiator in it and told him he should look. As you look at the image you can see that the cap/plug on the new radiator was a twin to the one removed from the lower hose. This is where it got better. He turned to me and said, “That couldn’t have happened, I took the caps off before the radiator was installed.” I closed with, “Well that’s what we found”.
A replacement radiator comes encased in foam with any and all openings plugged or capped. As you look at the image to the left you’ll see what Tony pulled out of the lower radiator hose. This little rubber plug just happens to be installed on the inlet and outlet ports of a replacement radiator.
The shop that replaced the radiator failed to remove the protective cap/plug from the lower port of the replacement radiator. The plug ended up inside the lower radiator hose resulting in a very random, coolant flow problem as the plug moved around in the lower hose.
Oh, the family dog? He is safe and sound at home. They did go back and pick him up when they figured out he was missing.
Northwood Garage handles over 25 brands of tires for your automotive needs.
We proudly provide expert auto repair and tire service to Northwood, Strafford, Nottingham, Epsom, Barrington and Deerfield New Hampshire.
Northwood Garage… Keeping your Car Good to Go! Since 1955
[gravityform id=”5″ name=”Quick Contact”]