Timing Chain Cover

[BlueST]

Hi, my first post but I've done a bit of searching but still have a load of questions. My Sister's Yaris is in a main dealer for service. Its a 1.0 vvt-i. 03 reg. The dealer has phoned to say the timing chain cover gasket is leaking and have quoted her £600 to repair. Now this seemed a bit steep, but after looking at a few threads on here it seems it's a common problem and quite a bit of work is involved. Am I right in thinking, cam cover, belts, pulleys and engine mount all need to come off? Also, I think another thread said the sump needs re-sealing. Does the sump actually have to come off, or is it just where it meets the cover?

I'm pretty handy with the spanners myself, so was wondering what peple thought about me tackling this with a Haynes Manual (I'll have to get one)? If it's going to take me three days of blood sweat and tears i might prefer to let the dealer do it. Are there any special tools required?

Whilst I'm in there, is it worth replacing the chain and tensioner at the same time? Anyone have rough idea of what parts I'll need and how much thet'll cost.

And finally, is the car safe to drive in the short term until it gets fixed?

Sorry to launch in at the deepend but I would appreciate any help you can give.

Thanks in Advance

Mike

[Black Knight]

To be honest unless it's loosing a significant amount of oil I'd just leave it be.

Try and understand the level of the leak. If it's just staining the engine and leaving black marks just leave it be. If it's flooding out might be worth doing.

Actually the repair is such a PITA to do chances are it'll be worse off by the time you get the repair done.

Only risk is if the oil leak is so bad you let the engine get low on oil

[BlueST]

Thanks Black Knight.

I was actually starting to think the same thing, I've not actually seen the car so I don't know how bad it is. I'll probably get a look at he weekend.

She NEVER checks the oil, or anything else for that matter, so if it's significant it will have to be done.

[Benno_uk]

The timing chain cover does not have a gasket. It is "sealed" using silicone sealant from the factory. This silicone sealant has been known to allow oil leakage on some petrol Yaris`s. Mr T is aware of this problem and there is a modified timing cover and special sealant avalible to cure the problem. Yes the sump on some Yaris`s have the same problem.

To re-seal the timing chain cover, it does involve removing rocker cover, offside engine mount, belts & pullys. It also involves removing the cam chain tensioner which is housed in the timing chain cover. So with the timing chain tensioner removed, it is possible for the timing chain to jump teeth and upset the valve timing. This will cause disasterous results if the engine is turned over with the valve timing out - so be flipping carefull! Im my experiance, if you try to re-seal using the original timing chain cover, you are wasting time. We have tried this a few times, the results not being very sucessful. Oh, and if you do order the modified timing chain cover, ORDER A NEW CRANKSHAFT SEAL TOO. As the modified cover comes without one and you will more than likley damage the old seal getting it out of the old cover. Good luck

Oh forgot to add, as long as the oil level is kept topped up, it won`t cause a problem to keep using the car

Just seen your other question, timing chain tensioners don`t usally give any troubble as long as they are fitted back correctly. The Haynes manual will show you how to re-set it before re fitting.

[MISTER MECH]

It also involves removing the cam chain tensioner which is housed in the timing chain cover

Just like he said, except for the above quote as you dont really need to remove the tensioner. You can work around it so you dont have the worry of the timing chain slipping. It is a bit more fiddly to remove the old grey sealant from near that area, but on the other hand its a lot less hassle than having to re set the timing afterwards. Also I advise getting a new "three leaf clover" seal for the VVTi controller which is also up near the top of the timing cover and DO NOT use any sealer to hold it in place whilst fitting the cover as it may block the oil way. It should stay in place but if not, use a small smear of grease to make sure it doesn't drop put.

Another thing to watch for if its just the cover you are replacing / resealing and not removing the sump too (yes it is possible to do without the sump coming off, just be careful not to crack the cover if its being re-used), is the woodruff key on the crankshaft. It has an annoying habit of falling out if the crank is not at TDC (pointing up to the 12 o'clock position).

Also the 17mm bottom pulley bolt is hellishly tight to undo. Slacken this off BEFORE anything else as trying to do so with the O/S engine mount off is a right pain in the ****.

All the best,

MM

EDIT:- Just re-read Benno_uk's post and had a thought. The T,chain tensioner is not in the cover. It's the VVTi controller valve thats bolted into it (just above the alternator). The tensioner is bolted to the cylinder head inside the cover. Maybe you got a bit confused, I know I was for a bit..

[Benno_uk]

It also involves removing the cam chain tensioner which is housed in the timing chain cover

Just like he said, except for the above quote as you dont really need to remove the tensioner. You can work around it so you dont have the worry of the timing chain slipping. It is a bit more fiddly to remove the old grey sealant from near that area, but on the other hand its a lot less hassle than having to re set the timing afterwards. Also I advise getting a new "three leaf clover" seal for the VVTi controller which is also up near the top of the timing cover and DO NOT use any sealer to hold it in place whilst fitting the cover as it may block the oil way. It should stay in place but if not, use a small smear of grease to make sure it doesn't drop put.

Another thing to watch for if its just the cover you are replacing / resealing and not removing the sump too (yes it is possible to do without the sump coming off, just be careful not to crack the cover if its being re-used), is the woodruff key on the crankshaft. It has an annoying habit of falling out if the crank is not at TDC (pointing up to the 12 o'clock position).

Also the 17mm bottom pulley bolt is hellishly tight to undo. Slacken this off BEFORE anything else as trying to do so with the O/S engine mount off is a right pain in the ****.

All the best,

MM

EDIT:- Just re-read Benno_uk's post and had a thought. The T,chain tensioner is not in the cover. It's the VVTi controller valve thats bolted into it (just above the alternator). The tensioner is bolted to the cylinder head inside the cover. Maybe you got a bit confused, I know I was for a bit..

I stand corrected on the timing chain tensioner. But I dis-agree on the "leave the engine mount on to undo the crank bolt" comment. If you do leave the engine mount on, you mignt get a spanner on the 17mm crank bolt. But when you find out its too tight to undo with a spanner and need to use an hex socket and 3 foot crack bar, you will find you cant get the socket on square. This is the time to undo the engine mount, to drop the engine a little, to get the socket on square. Cos if you round off said crank bolt, you`l be right up poo creek!!! :o And you`l also have to find a way how to stop the engine turning over when you are undoing this stupidly tight bolt too!!

[Black Knight]

As I said PITA to do :)

Essentially my esteemed colleagues above are right

Also make sure if you do decide to do it that you spend an AWFULLY long time cleaning all the surfaces properly before reapplying the sealant. You have to have got any residue of the old sealant off of and the surfaces have to be spotlessly clean of oil otherwise the sealant won't stick properly and you'll just end up with another leak.

Also once you've reattached the cover you'll probably want to start the engine to check for leaks. DO NOT DO THIS.

Leave it at least overnight for the seal to harden properly.

Again my advice is so long as it isn't gushing out leave it alone

[foggy08]

need to use an hex socket and 3 foot crack bar, you will find you cant get the socket on square. This is the time to undo the engine mount, to drop the engine a little, to get the socket on square. Cos if you round off said crank bolt, you`l be right up poo creek!!! :o And you`l also have to find a way how to stop the engine turning over when you are undoing this stupidly tight bolt too!!

how did you stop the engine turning over ? when i used a 9mm dia screwdriver jammed in the pulley spaces there was an almighty snap . we thought " **** we have just sheared the bolt ,but no we sheared the quality screwdriver . also does the sump have to come off to change the timming belt ?

[foggy08]

need to use an hex socket and 3 foot crack bar, you will find you cant get the socket on square. This is the time to undo the engine mount, to drop the engine a little, to get the socket on square. Cos if you round off said crank bolt, you`l be right up poo creek!!! :o And you`l also have to find a way how to stop the engine turning over when you are undoing this stupidly tight bolt too!!

how did you stop the engine turning over ? when i used a 9mm dia screwdriver jammed in the pulley spaces there was an almighty snap . we thought " **** we have just sheared the bolt ,but no we sheared the quality screwdriver . also does the sump have to come off to change the timming belt ?

[Madasafish]

need to use an hex socket and 3 foot crack bar, you will find you cant get the socket on square. This is the time to undo the engine mount, to drop the engine a little, to get the socket on square. Cos if you round off said crank bolt, you`l be right up poo creek!!! :o And you`l also have to find a way how to stop the engine turning over when you are undoing this stupidly tight bolt too!!

how did you stop the engine turning over ? when i used a 9mm dia screwdriver jammed in the pulley spaces there was an almighty snap . we thought " **** we have just sheared the bolt ,but no we sheared the quality screwdriver . also does the sump have to come off to change the timming belt ?

You can make up a Y shaped piece of metal with two bolts in the top two ends of the Y - which screw into the crankshaft pulley. The long end catches on the ground - or the subframe and stops it rotating. I made my own and will attach a photo later..

You do not need to remove the sump.. just need lots of sealant between chain cover and gasket.

BUT.. when you remove the chain cover there are two holes with access to the sump. You MUST seal those off or dirt will fall into the sump.

Edit

See this article for details and pictures

http://www.toyotanation.com/forum/showthread.php?t=395220

[foggy08]

finaly got the crankshaft bolt off . had to borrow an impact gun( snap on ) from a friend . took it off in a few seconds . didnt even need to lock the pulleys .

[Steve Behn]

We have a 2003 Yaris 1ltr petrol with a leaky crankshaft oil seal. The haynes manual say its possible to replace without the timing chain cover being removed but it's a bit tight. Any experience of doing this? Can it be done? Thanks in advance. 

[Madasafish]

Yes BUT

You need to remove the crankshaft bolt.

See above...

 

Having done it once when I replaced the chain on son's Yaris I would never do the job again. ..... ever

[Caroline Don]

Would a Blue Devil product, like “stop oil leak” or something more specific for timing belt cover reseals, work to help this issue without spending the 2,300 the dealership I bought my Yaris from wants to charge me to fix it. Ironically, they also want to buy it for trade-in from me for 2,200. 

[TonyHSD]

32 minutes ago, Caroline Don said:

Would a Blue Devil product, like “stop oil leak” or something more specific for timing belt cover reseals, work to help this issue without spending the 2,300 the dealership I bought my Yaris from wants to charge me to fix it. Ironically, they also want to buy it for trade-in from me for 2,200. 

Hi, 

you can try wynns oil stop leak is one of the best on ten market and does not affect oil viscosity or grade. Just fill in on warm engine and drive as usual. 
This will only help if you have silicone seal or gasket dried out and will eventually make these elastic again and bring more life to all rubber and silicone seals. It will not make anything worse. If the seal in question is broken or missing this or any other additives will not help ans only repair is your option. 
You don’t need to repair minor oil leaks in most cases ans many garages especially main dealers issuing these as safety excuse to accumulate extra work and increase profits. Seek a second opinion and see not records. I have a leak since the car was at 60k miles, I didn’t repair it and now the car is at 270000 without any further issues and also passes not without any advisories. 
https://amzn.eu/d/dcivh1D