Hey guys,

Sure would appreciate some advice on the following:

Yesterday I took my 2010 MCS with 24K miles to the dealer for oil change. They discovered I had a leaky thermostat and nicely repaired under some emmisions warranty. Very nice of them to take care of that.

Later they told me my car was ready and I saw my SA and chatted while waiting for the car to pull up. As an aside he mentioned that they also discovered a small leak from the timing chain tensioner. He suggested that I keep an eye out for any oil leaks or if the car rattles. If so, bring it in.

I got back home do a bit of research when I found all the info on tensioner and timing chain problems, recalls etc..

Just wondering how to deal with this. It sounds like the leaking is just the begining of a bigger problem and I would like to be proactive.

Any advice?

 

I remember seeing another post where a tensioner had the attaching bolts become loose, causing an oil leak as the tensioner "left" the engine just a bit. I am kinda surprised that your dealer didn't check for a backed-out tensioner. This can not only cause an oil leak, but also not enough tension on the timing chain, which can cause the entire timing chain system to fail, leading to the dreaded "death-rattle", and possible complete engine failure. Maybe someone here has a link to that?

Bottom line, I would say take it back to your dealer and ask them about this.

 

this is a tough one. i would check if it is covered by them/warranty to proactively fix the issue and replace the whole timing chain assembly.
if they refuse, take a look at the bolt and see if it started becoming loose.
also, ask them for service records of the car so you know what has/has not been done on it.

 

They should have dealt with this just like they did with the thermostat housing. Changing the tensioner is a really simple job and the part isn't even expensive. Glad you are having some good service from your dealer but this should have been sorted out or at the very least, they should have come to you to discuss options. JMHO

 

Thanks for the replies.

Really surprised now that the SA had little or no concern about this as I was leaving. I'm the original owner and have been going to the same dealer we purchased the car. Never an issue with timing belt or tensioner. But with only 24K miles, this type of problem is a bit of a surprise.

If there is a defect with the timing chain or tensioner, there does not seem to be any recall but lots of complaints.

Back to the leaking tensioner. Is it possible that the bolt was just loose? or, is this an indication the tensioner is failing. Or, to put it another way, are there more than one reason(s) the tensioner could leak oil?

 

Hopping on this thread to subscribe. Our 2010 MCS just started a rattle in the tensioner which goes away when oil pressure comes up. About 30k miles. No oil leak. Independent shop says to just change the oil and see if that helps. Waiting to hear from the dealer.

Is the tensioner mounting bolt mentioned above easily accessible? If so, where is it?

 

I think it is somewhat easy to access. You have to remove the air filter box amd the elbow pipe going to throttle body.

 

Take a look at the illustrated parts list --- http://www.realoem.com/bmw/enUS/select you'll need the last few characters of your VIN. You might be able to get by with only a new o-ring.

 

Oldbrokenwind - I saw your post on a another forum regarding a similar situation. With a 2010 MCS with the only symptom of a slight external leak from the tensioner, the remedy could be as simple as replacing the gasket on the tensioer and re-torque. Or, replace tensioner since removing anyway.?

In the other thread it was pointed out that there were some 2010's that did not have the tensioners installed to proper torque.

 

Here's a pic of my tensioner. You can see that there's no other area except the o-ring, or very soft and fancy washer, for a leak to happen. The hole / indent on the outside surface (not shown) is for centering the item when being fab'd --- it doesn't go thru. OK, mine is an '07 vintage, but it's not likely to have changed enough, structurally, to have any other source for leaks.

As for replacing it "while you're in there", that's a subjective call. Spring and internal seals could deteriorate over time and miles. It's question of convenience and budget.