- Car Care & Maintenance
Do it myself Honda water pump replacement.
How do I know if the water pump is failing?
I can't stop myself from doing automotive repairs completely. After 35 years of running auto shops, every now and then I need to get a spanner dirty myself on jobs I don't trust an auto shop to do.
Water pumps are one of those jobs I will not trust to anyone else. You will see in the photo of the Nissan water pump why I don't trust others to replace my water pump.
Water pump failure destroys many motors, even more than broken radiator hoses or leaking radiators, because you need to replace your water pump BEFORE it stops functioning!
There are three pretty reliable indicators of pending water pump failure, two of them are 100% accurate.
- Look for even one drop of coolant that has dripped from under the front of your car overnight. Not a big puddle, that is likely to be a different problem, just a drip or two. This is likely to be coming from the relief hole in the front of the water pump, and by looking up, you may see a drip on the bottom of the water pump. If so it is dead.
- You may also see a powdery white coating on the front of the water pump that is corrosion caused by the coolant getting past the water pump bearing seal. 100% fatal.
- You may hear a tiny grinding sound that changes with engine revs, and I know that sound well on any car. It is distinctive in it's metal grinding sound and means that the water pump bearing seal has been broken for some time, allowing the bearing to become damaged by the particles in the coolant. If you remove any other driven components such as the alternator or power steering pump belt, you will be more certain if it is the water pump making that noise you hear. As the pump gets closer to complete collapse the noise will become louder and sound even more like metal being ground against metal which is what is going on inside the pump bearing.
Having to replace my Nissan utility water pump recently (it's done 235,00 klms.) I got a lift down to the spare parts shop in my son's Honda. I had phoned my parts supplier to confirm the pump was in stock, then pulled the pump off the ute to check it against the replacement to ensure proper fit.Some vehicles when new, had 2 different water pumps in the same year of manufacture, so it pays to check it against the replacement water pump to ensure it will fit your exact model number.
On the drive down to buy the Nissan water pump, I could hear that familiar water pump grinding noise that preceeds water pump failure coming from my son's little Honda, so we got a water pump for the Honda at the same time. It cost AU$80.00, a little dearer than the Nissan one and stamped with the original equipment logo. Exactly the same part that was fitted when the car was new. I have been using the same supplier for 30 years, as he really knows his business.
The Nissan pump was easy to access.
I refuse to use cheaply made after-market moving parts as they often fail without warning, and if that happens to the water pump there is a good chance of instant overheating resulting in an engine rebuild. Never drive with a hot motor, it kills the engine internals by altering the metal and doing serious damage that will cost thousands to fix. If you turn off the motor immediately, in most cases damage will be minimal.
Always use high quality replacements for all moving parts such as water pumps, wheel bearings, tie-rod ends, idler and Pitman arms, suspension bushes, struts, links, springs, alternators, disc brake rotors, in fact any moving part. You can buy cheap replacements for body panels and other static components but even then you can expect problems with fitting them, as they are seldomm perfectly formed, and bolt holes may be off centre.
You can see in the picture that the pump was badly fitted the last time it was changed.
Typical water pump supplied with dry gasket.
Buying the parts.
The owner of my parts supply shop is first and foremost a good motor engineer himself and all his parts are OEM equivalent or better. His prices are often half what the dealership wants to charge me for exactly the same part from the same manufacturer with the same part number.
If you have a friend who knows a lot about cars and does his own repairs, find out where he or she buys spares. You may get lucky and find a place that has knowledgeable staff at the counter. These guys are dealing with mechanics and auto shop owners all day so prices are close to wholesale because the smartest auto shop owners will always track down parts that are highest quality at the best price.
If your referring friend knows his spare parts shops and has pointed you in the right direction you will be surprised at the level of service, product quality, and guidance freely given with the refit of the part. These guys will usually inform you of any little tricks to ensure you don't make any mistakes, as this is the level of service that the smart auto shops expect and get.
Don't bother with the McDonalds type of cheap auto parts shops. They are useless for advice, and sell bad value for money consumables of dubious quality,
You will find the cheap junk parts are only about 5 or 10% cheaper than you will buy a quality part at a shop that is more engineering focused and a major supplier to the better repair shops that have highly skilled mechanics who already know not to use rubbish parts..
Some O.E.M parts ( from the manufacturer of your vehicle or original parts) are prone to failure due to poor design and thereby need a better replacement than the original to be trouble free.
For example the original cam chain and adjuster on Renault Scenic's are not worth the work involved in fitting them. As the standard part was crap, my replacement parts guy only stocks a high quality modified cam chain tensioner with a stronger belt. Because I have an old established supplier I hardly ever need to go elsewhere no matter what make of vehicle I am working on, they have the parts I need, or can get them for me usually the same day.
Even when using the best quality water pump, things can go wrong though.
Before fitting the new Honda water pump I pulled it out of it's box and turned it slowly by hand to ensure the bearing and seal offered the right amount of resistance to being turned. A new pump will not spin, it is easy to turn but slightly stiff because of the very tight tolerance.
As I turned it I explained to my son that I always check every new part before fitting, as although the chance of getting a faulty part from my supplier was minimal, I try to avoid doing any job more than once, so don't take any risks with part or fitting.
I revolved the pump slowly and ........... found a potential problem! In one spot I could feel a slight variation in resistance so that it had this tiny tight spot in each 360 degree revolution by hand.
Years of working with fine engineering on racing motorcycles has taught me to be very suspicious of such anomalies, so I took the water pump back to the shop to exchange it.
I handed the pump to one of the spare parts salesmen and he turned the pump many times but could not detect any tight spot. The staff obviously enjoyed this challenge and passed it from one to the other each diligently trying to locate the spot and demonstrate their ability to me. No luck. They were as always, willing to do anything at all within their power to help and immediately offered me another pump. I agreed eager to get back home in time to do the repair. Then the computer had some bad news, no stock until tomorrow. So Ray, the engineer that started the business and I both examine it, and disovered that the more we revolved it, the less we could notice the problem. We decided on a few theories that would be acceptable explanations and decided to fit the pump anyway as Ray reckons it would be OK. He buys thousands of these things and has not had more than a couple of doubtful returns, so I am very confident in his knowledge.
This Friday we decided to replace the water pump. My 20 year old boy did most of the work with directions as to which order to proceed in.
Most water pump replacement is dead easy these days, it is getting to the pump that takes the time, and providing you ensure that the "o" ring or gasket is in place and both surfaces are clean they are easy to replace on the cylinder block or extended housing.
The Honda has an air-conditioning mounted in a caste iron housing that would support a house. Although this is fitted by Honda, it is not OEM, but fortunately with Honda's strict adherence to quality control it is strong and does not allow any vibration.
It is also bolted on very tight, so we needed quality sockets and ring spanners to undo the support bolts which we did not have at home.
The procedure is
simple enough, but easy if you get the steps right. In this case it was
remove the air cleaner, the inlet manifold heater tube, the pulley of
the end of the water pump, loosen the rocker cover, then the cam belt
cover, undo the four bolts holding the water pump on, then pull it off
past the loosened cover which partly covers the water pump which is why
it needs to be loosened. If you mistakenly loosen the very tight 12mm
bolt in the centre of the cover, no harm done, when you re tension the
bolt it will have simply allowed the cam belt tensioner to readjust
itself as it would be done in service.
Even doing the job in
the driveway with a few hand tools did not take more than a couple of hours, apart
from some time lost in removing the air-conditioner mount with our cheaper than cheap
spanners. As the Honda has rubber sections in the air conditioner compressor lines, we did not have to disconnect the hoses which meant no need to recharge the air-conditioner.
We took a fare bit more time than needed cleaning the
chassis and inner fenders while we had access, replacing the odd light
bulb and generally giving it some of the care it should have been
getting a lot more regularly!
All in all any easy afternoon's work, and my son now knows a lot more about looking after his car.
After replacing the water pump you need to bleed the air out of the system after you partly fill it with coolant until it covers the top tank. Then squeeze and release the lower radiator hose until no more bubbles rise out of the radiator filler cap and the fluid level drops. Top up and repeat until the radiator is full and there are no more bubbles.
Run the motor with the radiator cap loosened until all the bubbles have gone, but not long enough to get the motor warm. tighten the filler cap with the radiator full but not the reserve bottle. Run the motor while watching the temperature carefully. Switch off.
Wait 20 minutes then open the radiator cap again and run the motor. If coolant pours out the top, you still have an air lock. Try squeezing the lower radiator hose again half a dozen times, watching for bubbles.
Watch the cars operating temperature for half an hour to ensure it does not suddenly overheat from air trapped in the system. Many systems will self bleed with the cap removed, others are a nightmare and heaps of care is required. That will require another hub.