Ametcalf

I have quite a rattle on cold starts. Does anybody have an idea how much it costs to have chain tensioners replaced? 99 996 with 100k miles.

dporto

^^^An arm and at least half a leg... you probably don’t need the tension era themselves replaced - only the pads. You can only do the cam chain pads. Probably in the ballpark of $1500 to $2k... In order to do the main and IMS tensioner pads, you need to split the crank case...Take it to a reputable shop for an estimate...Mo money!

Ametcalf

So, probably better to wait when I have the IMS done again?

Noz1974

The tensioners themselves are about £80 GBP each , it is worth changing them as when they get older the oil leaks out when the car is parked and on starting they have to pressurise from the oil system to give proper tension on the chain hence the rattle , I would say it's more the tensioner than the paddle myself really! On the 99 it's ok to just lock the crank at TDC and then remove the tensioners , two are really easy to do literally underneath the engine , takes like 30 mins for both no need for $$$$$, the ims tensioner and bank 1 tensioner , take the new tensioner out of box , place some oil in a plastic container , submerse the new tensioner in it, pump the piston with your thump until it pumps up, use a new crush washer and bolt in to correct torque, it's one of the easiest jobs I've ever done on my 996 , the hard bit is bank 2 the tensioner is on top of the cylinder head instead of underneath and I think you need to remove the air con compressor to get at it but I'd say do the two underneath and see if it improves any then look at maybe the other one after that!

Ametcalf

Noz1974, thank you!

Ametcalf

How do I lock the crank and what is TDC?

pdxmotorhead

If those two items are a question.. Stop and back slowly away from the engine.
Your many hours of reading and searching.. away from being ready to DIY this..

If your just messing with us ,,, well played...

Weazer

Just did the tensioners on my 99 Boxster, was able to do all 3 without disturbing the AC compressor, however, there was much foul language which decorum prohibits the repetition of here. I think my head twisted around 360 degrees at one point ala Reagan in "The Exorcist" (or was that the great 996 coolant reservoir replacement debacle?) Anyway, I second pdxmotorhead's suggestion to the OP of doing much more research/reading before attempting this as a DIY, yer messing with your cam timing here and if you pooch the job you could have your timing chains skipping teeth on the timing gear inside the engine. Just sayin.

Mike Murphy

I just paid my mechanic to both bank tensioner pads on my ‘99 (64,000 miles). They were both worn. It was $4,000, including a $500 failed solenoid on one side.

808Bill

Once the chain rails/pads start to wear, they go fast (I've read) and should be replaced sooner rather than later. Will new tensioners take up all the slack in a worn pad?

Mike Murphy

My cam deviation went back to (0,0) from (-3,-2) once the pads were replaced. I assume the chain slack is now tighter, but I would guess only on cold start. Once the tensioners have sufficient oil pressure (they are the last endpoint in the oil deliver system in the engine), I would expect the chains to be tight when the engine is running in either case.

Metty

My mechanic is showing 0 on cam deviation

Noz1974

I wouldn't say so , the tensioner will take up the slack anyway but new tensioners might reduce wear, I would say the point on start up where the pad is vibrating against the chain before the old tensioner pumps up is the worry causing excessive wear !

Noz1974

The crank pulley has various holes in it , one is to lock the crank at Top Dead Centre, this is a datum point for the engine where cylinder one is at the top of its stroke and is deemed the beginning of the engines combustion cycle, it is used to set the bottom end of the engine I.e pistons with the timing of the cam rotations and valve openings to ensure everything runs properly and opens and closes as it should in the right time to make the engine work properly , in this case it just locks the engine at a certain point , the five chain which you have isn't bad for skipping chain links on timing when you remove the tensioners etc, that's why you have to pump up the new tensioner with oil so the chain is not slack on start up causing a jump but I'm not sure if it would happen on the five chain , if you research locking engine off at TDC on here you will find the info you need , basically when the crank is in a given position the TDC hole in the crank lines up with a recess cast into the block behind allowing you to insert a timing fowl into to stop any rotation on the engine or just make sure it stays exactly on the TDC spot , you don't need the special dowel though , just use a bolt that fits in there quite well, but as others have said use a bit of caution if your not confident don't do it ! The only hard part of the job I had was once the tensioner is pumped with oil and your trying to insert it into the block and start off on the threads to screw it in it can be a bit hard to get started as it's extended and there's a bit of backwards force there , this requires a bit of pushing on the head of your ratchet to depress the tensioner into the whole so you can get on the thread and because it's a bit awkward there's a chance you could hit a cross thread but if your careful you should be fine , once you get on the thread just tighten up to the correct torque and that's it ! Another note , each tensioner is unique they are not all the same , one has a plain head ( the top of the nut) , one hasone ring groove on the head and one has two ringed grooves so you can identify them, it sounds like it's getting complicated this but it's really not !

Metty

I’m trying to upload video of rattle but have been unsuccessful thus far. I tried copy and paste from YouTube and it did not work. Any ideas?