just curious, in general, for an older car (200K miles), would a shop, when replacing the timing belt, normally advocate to replace the cam shaft seals as well (w/o an indicated issue like cam shaft leaks)?

Or would they just do the timing belt and defer doing the cam shaft seals for when there is a leak?

Seems like it's typical to do the seals when doing the timing belt but not sure. If the shop didn't recommend the seals when doing the belt, should I be looking for another shop? Or is it judgement call?

Never been asked that and I had a WRX that run 200K miles. At 200K they usually recommend replacing follower bearings that guide the timing belt. Also the water pump on Subarus since it is driven off the back side of the timing belt and a 300K mile water pump is a stretch...

Wait. Trying to understand. The WRX doesn't need a timing belt change even after 200K miles, and so the cam shaft seal question is n/a.

Or they never ask about the cam shaft seals when doing the timing belt, bearing, water pump?

No idea about that WRX. what year? and to the OP what engine in what vehicle, it matters on the discussion.

Hmmm, my only engine rebuild experience was with a small block Chevy (327). There weren’t any seals on the camshaft. Of course, it had a timing chain instead of a timing belt, so that was different too.

quote:

just curious, in general, for an older car (200K miles), would a shop, when replacing the timing belt, normally advocate to replace the cam shaft seals as well (w/o an indicated issue like cam shaft leaks)?

Parts that rotate with the belt (idler/tensioner pulleys, water pump) and external tensioning device if any, yes. Cam seals, no, not if they don't leak. Too much to go wrong. Getting the bolt and sprocket an inch from a strut tower off (rear/firewall side/right-hand bank of Toyota V6) is bad enough, taking a nick or gouge out of a journal or cylinder head from removing the seal, folding the seal lip over or getting it in crooked is worse. Not all "preventive maintenance" is worth the trouble you can get into.

Any particular car we're talking about? Chances are pretty good that I have done this job on one. If it has a belt at all.

An energized lip seal after many miles has mated with the rotating shaft. Moreover the seal uses a film of lubricant and molded diagonal features to recirculate lubricant within seal to keep it inside the engine.

What causes many seal leaks is lubricant oxidation and follow on deposits that are hard and sharp. Keep oil changed to minimize.

Seems like this is one of those, "we're in there anyway, might as well do it," situations. It it isn't too much $$$, I'd probably go ahead with it. You'll thank yourself if, six months down the road, if the seal were to fail.

Seals are wear items, just like the timing belt, if they are in there and it's a 200K mile engine than agree it's probably a good idea vs having to take it all apart again.

Changing the seals is the most delicate part of the operation, along with setting belt tension if it is manually set. I might not trust a heavy handed parts changer to do it properly. It involves removing the seals without damaging the seal bore or the sealing surface on the cams. Is the replacement seal the same quality as the original? I might specify OEM, maybe a cheap belt kit might have seals from an unreputable source. I'm skeptical of most rubber products from a particular far eastern country.

Some seals may require a specified sealant and depth or the depth adjusted if the previous seal left a groove in the sealing surface. Seal installation tools can be critical and general tools may damage the seal.

So you are balancing if the mechanic is qualified to do a proper installation and install a quality seal vs will the original outlast the new belt.

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Seals are wear items, just like the timing belt,..

Disagree. They are not just like the timing belt. Every part of the engine where parts make contact and friction is a "wear item." Timing belts are a scheduled maintenance item, done by mileage and sometimes time. Pulleys, water pumps and external tensioners are relatively easily replaced, cam & crank seals are not. Pulleys, water pumps and tensioners also fail much more often than seals.

Also be sure nothing in the PVC system is causing positive crankcase pressure.
Any seal will leak under that condition.

Thanks guys. Sounds like it's a little more complicated than I imagined with perhaps not a consensus general rule. I guess water under the bridge for now.

I only replace them if they absolutely need it.
I prefer not to remove the camshafts and separate the gear from it if I can avoid it.

Okay, thanks. I'll not fault the shop for not doing the seals when we did the timing belt a year ago.

Sucks to be me though. $1500, all labor, to replace seals.... sigh. I'm desperate to keep the car alive for another 3-5 years though. But approaching my cut bait limit.... One more expensive repair and the car - boom, to the moon.

Similarly, I didn't make it a standard practice to replace the seal in a transmission or differential that I pulled an axle/drive shaft out of if they weren't leaking before. Don't nick, cut or otherwise damage the seal, whether on removal or installation, and they don't leak. Some of these seals, like those of the cam and crankshaft, are difficult to either remove or install without damage. Out of probably hundreds of these jobs that I did, only a tiny number leaked afterwards.

Yes! Absolutely. It may depend on the make and model of car somewhat.
I always request that they be done if I’m not doing it myself. And it’s absolutely a case of while you’re in there.

Some timing belt change kits even come with the gaskets AND the seals already. The only thing you need to watch for is they don’t charge you for full labor for replacing the seals from scratch, they shouldn’t be adding more than an hour of labor probably even less… again, depending on the particular car/engine.