Honda J35 (V6) '04 Odyssey -Valve Grind Necessary?

[92saturnsl2]

My g/f and I bought an immaculate '04 Honda Odyssey with 136k miles on it for a tad under 5k a few months ago. It drove flawlessly when we bought it, but we soon discovered it had an appetite for coolant, and if you didn't appease it, it would overheat.

Looking through old service records, the previous owner had several bouts of overheating which was never fixed, then they traded the car in. Now we're the proud, happy owners of a Honda with a bad head gasket.

I pulled both heads off, and the cylinder nearest the battery (front driver's side) had been ingesting coolant, the gasket was visibly bad in this area. All other cylinders looked okay.

I took both heads to a machine shop which a buddy from work recommended, thinking I'd have them check it for flatness and be on my way. They quoted $30 to check for flatness, $130 if they have to mill the head(s). -- I got the surprise of my life when they called me today and said that they vacuum checked the heads/valves, and the heads tested poorly. The recommend a valve regrind to the tune of $410, and that's if they don't have to replace any valves. They didn't mention the condition of the valve guides.

I brought them my own valve seals to be replaced, so they'll be replacing seals as part of that price (labor only), along with cleaning and checking the heads. Is this a worthwhile investment toward this vehicle? I checked compression before pulling the heads, and all cylinders were fantastic; IIRC, all were between 200-210. I was under the impression that Honda heads rarely needed work beyond just making sure the heads weren't warped because of a bad overheat, and that I could throw new headgaskets in and be back on the road.

Already I've invested about $350 in parts (timing belt, water pump, full head gasket set, valve seals, etc.), and now another $410 just in machine shop labor? This is starting to approach engine rebuild territory, considering that I'm doing all the labor other than the machine shop.

Is this place trying to take me for a ride, or is the expense justified? I've never had work done at a machine shop, so I'm a novice in this area. I've done all my own wrenching on my cars other than that. Should I call around for price comparisons? Ideally I'd like to get another 5 years out of this vehicle, which would mean another 100k or so.

Any help, input, suggestions, etc. would be much appreciated!

 

[bullwinkle]

With 210 compression numbers, I'd be tempted to leave the valves alone, as long as the guides aren't bad.

 

[JHZR2]

Used cars can be such a poor value. Seems like youre getting caught in a value trap.

Here's how Id look at it. What's the worst that can happen at this point if the rest of the van is immaculate and well kept?

Id argue that the engine could fail and the transmission could fail. The AT is probably a $3500 job, the engine as well.

If youre eating the labor and doing it (and getting the timing belt, probably a few other tune up items, etc.) completely, then the only other biggie that you could run into is the AT.

So if you like the rest of the van and its in great shape, then fix the engine completely, do a complete and proper job to baseline it like new, and then set up a sinking fund for the AT for the day that fails. I figure you have about 25k miles left before that happens.

So then the question is if the shop is taking you for a ride. Honestly Id tell them that you tested compression and got 210 and thought that was good, so wanted to get a second opinion. Go to another shop, get the opinion, and then do the work with who you like best. Its a $100+ gamble, but so is putting something back that hasn't been properly serviced, based upon one measurement that could have been flawed.

Good luck!

 

[tomcat27]

a compression test is not as conclusive as a leakdown test. I'd follow the advice of the machine shop and have the valve grind done. you've invested time, parts and labor to get it this far; might as well do it right. of course, that's my general approach. ditto on that transmission being an expensive time-bomb. although you do have a van that should have no problem getting 200k+ miles on it (except for the transmission and head gasket)

 

[goodtimes]

You have your own test that showed compression was good, you seem to know what you are doing by asking for a flatness check. A precision bevel edge straight edge held against strong light will show any defects in flatness. The kind with the plastic cover over the holding side. I think the Chinese made ones are pretty cheap. I used to have a Mitutoyo one but those are not cheap. These can show down to a couple microns any deviation. Far better than the machining itself. A regular straight edge with feeler gauges is a more standard way, not as accurate. Or ask them for the results you wanted before paying the $30. You seem to be on the logical track, if the head isn't warped, it can go back on with a new head gasket and that should take care of the coolant problem. Which was the only problem as you described it. Valve grinding to an interference fit three angles and to size is a highly precise process, and the factory is hard to match on that. If you DIY when you put the new seals in you can visually check the valves, guides, and seats for damage. I hate to give advice on an anonymous forum, so take it with a grain of salt, but good luck with it.

 

[The_Eric]

Originally Posted By: tomcat27
a compression test is not as conclusive as a leakdown test. I'd follow the advice of the machine shop and have the valve grind done. you've invested time, parts and labor to get it this far; might as well do it right. of course, that's my general approach. ditto on that transmission being an expensive time-bomb. although you do have a van that should have no problem getting 200k+ miles on it (except for the transmission and head gasket)



Agreed.


A lot of people get wrapped up a vehicle's value or worth, which is fine if you're going to sell or trade it off within X amount of time/miles. However if you intend to drive it into it's grave, who cares what money gets put into it (within a reasonable amount) as long as cost per (projected) mile driven doesn't creep up to new or newer vehicle pricing, repair away!

If I remember correctly, you got a great price on it, right?

So, if you got it for 5K and end up putting 1K in head work and 3.5k in transmission (assuming worst case), and maybe 2K in incidental repair (beyond typical wear items that any vehicle will have), you've still got less than 12K in it. If you drive it for another 100K miles, you're looking at 12 cents per mile.

What about cost per year? Going off of 12K miles per year (100,000 miles/12,000 miles per year), that's 8.3 years or 1445.00 a year ($12,000/8.3).


KBB is saying 3500-4K trade in or 4500-5000 private sale. So if you trade it off on a new or newer Honda minivan, you're still looking at 20-30k depending on year and trim of course. At 25K purchase price, you would have it drive it 200k miles to equal the cost per mile of the older unit and I didn't factor in any major repairs. Sure, it's worth more money- but your pocket book will certainly know it too and you will have to own it twice as long for the cost per mile to work out.

At 12k/ year, that's 16+ years at 1500+ at year on average. Assuming a 5 year loan, the first 5 years will be more like 5500/year or higher.

 

[tdpark]

Well- I have a on 04 with 260k on it- so if that is the only issue and you take care of the tranny- the van will last for a long time. goto odyclub.com for more info on fixing things like the power doors if your van is equipped with them.

 

[HangFire]

Grind the valves if you plan to keep it for more than 100K more miles. Don't bother if you're going to trade it in after a couple of years.

 

[Vikas]

what is the reason that valve grind is necessary? apart from machine shop saying it is needed. would you know after getting the head back if the valve grind was actually done?

There are quite a lot of those era van at 200K+ miles without engine being touched; not even the valve adjust done on them.

 

[92saturnsl2]

I decided what I'm going to do is go down to the machine shop this afternoon and look at the cylinder head myself, and have them show me the heads and why they recommend the valve grind. I'd also like them to tell me what they think of the condition of the valve guides. I do not want the costs to keep reaching for the stars as they uncover more things that need attention.

My hunch is that if the valves are in poor condition and leaking, I should see evidence of that on the valve or seat, correct? Pitting, scoring, etc.? Or is the damage/wear too minuscule to see with the naked eye or magnifying glass?

I do have every intention of driving this vehicle as long as possible-- I bought into the Honda reputation for reliability (instead of opting for a Ford or GM model) because I knew I'd be hoping to get to 200k or beyond with this vehicle.

I don't want or need a high performance race engine, just something reliable to get from A to B. Other than the head gasket, the engine performed fine, had great power, mileage, etc. Nothing would have suggested the heads were in poor condition for the mileage. I just don't want to spend money on something that won't yield quantifiable results...

 

[Schmoe]

If you're in it this far, I'd go all the way and have the piece of mind.

 

[CBR.worm]

Generally speaking an engine will run better with freshly cut valve seats and properly lapped valves. I don't know what condition the valves or seats are in, there may not be any visible evidence of a non-perfect seal, but there may be wear and/or pitting depending on how clean the intake air is.

If it were my engine, I would do everything. Valves, guides, springs, check cams and research to find optimal valve angles for efficiency/power. Maybe optimize the ports. I would also mill an appropriate amount from the head and possibly deck the block (probably not realistic in your case). I don't know if slotted cam sprockets are available, but you could optimize the valve timing taking into account the shorter stack-up. Essentially I would take it to a honda guy who knows those engines and could get you some 'free' horsepower and efficiency, possibly at the expense of needing better gas.

I don't know what the right answer is for you, I am sure it will run fine as is. Would it be a noticeable improvement to have a valve job? Probably - if they do it right. Maybe not enough to be worth it for a family hauler.

The flip side is that if the valves are adjusted now, with the valves and seats already beat in, you should never need to adjust them again, if you do a valve job you should go back in at some point and readjust the valves after the pound in for a while.

Money probably better spent on a weekend racer...