'06 Honda Odyssey with 120k, never serviced...what would you do?

@GeorgeSanJose, consider changing the O2 sensor. My '92 Celica, 4A-FE missed emissions by just a tad high over on HCs. Everything else was correct, so a new Denso O2 sensor from RockAuto.com for about $35 fixed it.

I’ve been thinking of doing that @BustedKnuckles , just worried the replacement O2 sensor may not work properly, and will be introducing problems I didn’t have before. Don’t want to move the ball in the wrong direction. But since you’ve done this successfully with exactly the same engine, and it improved the HC’s, I think I will in fact follow your advice. Thanks for the excellent info.

Make sure you use a Denso sensor, the OEM supplier to Toyota. I tried a Botched sensor in my Supra (from AutoZone), and the ECM did not like it. Changed it out for a Denso, and all was good.

Above all else, I’d get that timing belt and water pump replaced. That could be a ticking time bomb at that mileage.

I have an 05 Odyssey with almost 140k on the clock. It’s been dealer serviced as scheduled since new. Runs like a top. I also pull a trailer without the official towing kit. It boils down to weight. The official towing kits adds a transmission cooler and maybe a power steering cooler and/or HD radiator, resulting in 3500lbs towing capacity.
Without all this gear, the rated towing capacity is 2000lbs. I pull an aluminum trailer with two dirt bikes or one street bike depending on the weekend. Weight is around 800-1000lbs (trailer and motorcycles). I’m not expecting any transmission probs, but it would be a different story if I was pulling 3000lbs without the towing kit. Just sayin’

UPDATE: did an ATF change with Honda DW-1, two flushes and a fill, and the transmission is running very quiet and smooth. I think I had gotten used to a bit of noise so I was surprised to be able to hear the difference. Also changed the plugs but didn’t notice anything different. Moving onto brake discs and pads this weekend if the weather would cooperate for once. Timing belt and water pump are on my list but need to stretch the budget a little longer before ponying up for that.

Wrmerkel wrote:
Timing belt and water pump are on my list but need to stretch the budget a little longer before ponying up for that.

I wouldn’t wait very long. If the timing belt breaks, you’ll end up with a very expensive engine repair or replacement.

^ Ditto on that. Beg, borrow, or steal (well, not literally) the funds needed for the timing belt. That’s gonna cost you if it breaks.

You are 1 year and 15,000 miles over on the timing belt. Since you will replace the water pump and they have to drain the coolant, you might as well have it replaced, too.

Also, if you are towing with the vehicle, the best thing you can do to help your transmission survive is to install an external transmission fluid cooler, assuming your vehicle does not have one and is only using the one in the radiator.

It it were my car, or a recent acquisition, I would do a comprehensive inspection of the van to see what might be bad or worn out before performing catch-up maintenance.

All rotors and pads changed out this weekend. The Phillips head retaining screws were a b***h to get out of the rotors but after a good soak with WD-40 and a fair amount of hammering they all came out mostly unblemished. Brakes are silky smooth now. I was gonna do a coolant swap until I saw jtsanders’ post above about having to drain the system to replace the water pump, so I saved some time and a few $$$ by leaving that off the list. Thanks for that advice. After all that I did a vacuum, rug shampoo and Armor All on the whole thing, so I’m feeling pretty good about the thing for the moment. Timing belt will be done in May, so I’ll update again after that.

Good work! In the future, you can get the retaining screws in the rotors off with an impact wrench. I got one for less than $10 at a hardware store. It’s the manual kind that you hit with a hammer to loosen the bolt. You push and rotate the head to change from clockwise to counterclockwise action. It’s a lot faster than WD-40 and leaves no residue. I’d be concerned about the retaining bolts backing out if they were soaked with chemicals and not cleaned before installation.

These are all good suggestions. I am not familiar with this exact engine but not all Hondas use a timing belt. Some use a chain. If you do use a belt, get it changed ASAP. Also, this is likely an interference engine as all Hondas seem to be of that style. You will need to use extreme care if you do this work yourself for fear of damaging the valves. Remove all the spark plugs before starting so the engine won’t rotate due to compression. If you feel any part giving you resistance, DO NOT put any muscle or force at all into this. Basically, if you don’t feel comfortable doing this work, this is one to leave to the experts. You might do a flush of the cooling system as most of the coolant will come out with the water pump change and it probably needs to be changed after this long anyway. I would do the flush before the work as those flushes can be hard on water pump seals.

The transmission fluid flush/change is a good suggestion and it is good you got this done.

The timing belt is definitely not something I would take my chances with for long. Get this done ASAP! If you can avoid driving this car in the meantime, I would do this as much as you can.

Only on battery: I live in Canada which gets to -40 F in winter. Never kept in a garage.
My 98 Civic Coupe Si needs a new battery every 5 years. It dies almost to the month when pro rated warranty runs out.

@Gord777 You are the ideal candidate for a block heater. I understand that in Western Canada almost all cars are shipped with block heaters. If you get 5 years out of a battery you are doing well!

They also have battery blankets that plug in with the block heater. You may get a few more years out of a battery with one.