Warm start rattle solved on my car!

[JimmyBones]

Looks great man.

What did you use to paint the intake manifold and ignition coils/wiring harnesses?

[Priest]

Looks nice :-)
Sorry to post and ask in here. Anyone have genuine Audi S4 4.2 ecu map for tune? Could be 2003-2004 year. Thanks

[breal]

Both are automotive paint. The manifold was professionally done, ignition stuff was me. Curious to see how well they hold up.

I ended up having a vacuum leak from the front of the manifold. Took it off and redid the gasket. Give it another shot tomorrow.

[pandapod]

I did this to my car a couple weeks ago...i usually get a cold "rattle" and sometimes a warm start "rattle", but it doesnt sound like any other rattles i've heard, hence my quotation marks (my rattle is barely audible and i dont even want to call it a rattle). Regardless, replacing the check valves did not fix anything (probably because stock check valves were 100% functioning)

[breal]

Week and a half in and no more noise at startup. Kind of surprising since the valves seemed to be working. I'm happy regardless.

[Tugboatguy]

Week and a half in and no more noise at startup. Kind of surprising since the valves seemed to be working. I'm happy regardless.

They may have moved freely to the closed position and still leaked by at the seat.

[Mr. Corey]

Finally got my engine bay back together. Have a rough idle on first start up that I'll diagnose tomorrow. I'll report back over the next week with any start up noises.

More photos of this awesome engine bay please!!!!

[breal]

I'll be cleaning up the car for some photos soon hopefully. I'll post some pics in the photo thread afterwards.

[SquiddyB6S4]

If it helps any, guys, springs wear out from changing position over and over again. Just because a check valve can be moved does not mean that it is functioning properly. I have not held a worn out BHF check valve in my hand yet, and certainly some check valves do not have high mission critical preloads, but it is at least possible that although it is working, it is so weak that it does not properly shut. Also possible that the valve seat is simply worn out, which is honestly much more likely, as old valve seats rarely seal completely.

Just my two cents on the topic. Also, I always figured that if and when I undertake a timing service, I would go ahead and replace the oil pump itself, both for cheap insurance over time and to bring operating pressures back to original specification. It's a basic rebuild part for any engine.

[alcatranz518]

Found this morning after doing the flapper cleansing and wanted to share. I split the intake since after I did the cap cleaning the rattle was still present. Very glad I did as I found something that could have been a HUGE disaster. So just in case, here's what I found for all you. Hopefully this is another surprise the toad of a P.O. left me and not something the manifold does over time. (She has 141k on the clock).

If you look at the pics below, there's (4) gold T30 screws circled in red on the upper and (4) gold T30 screws circled in red on the lower intake manifold plenum halves that when I separated the intake, I found them not only loose but extracted about 1/16" out of the threaded holes. After a brief but much needed anxiety attack I tightened them back down and torqued them to about 20 in-lbs with (blue locktight as well) then conducted a thorough cleaning throughout the entire intake manifold.

BTW...that partial polish job on the upper intake plenum ports was properly finished and done to the lower, I didn't leave it like that. Just wanted to take the pic before I got too involved ;)

[breal]

If you read over the past few pages, those screws are discussed, as well as at least one thread recently. It's an Audi issue.

[mistral cytz]

Found this morning after doing the flapper cleansing and wanted to share. I split the intake since after I did the cap cleaning the rattle was still present. Very glad I did as I found something that could have been a HUGE disaster. So just in case, here's what I found for all you. Hopefully this is another surprise the toad of a P.O. left me and not something the manifold does over time. (She has 141k on the clock).

If you look at the pics below, there's (4) gold T30 screws circled in red on the upper and (4) gold T30 screws circled in red on the lower intake manifold plenum halves that when I separated the intake, I found them not only loose but extracted about 1/16" out of the threaded holes. After a brief but much needed anxiety attack I tightened them back down and torqued them to about 20 in-lbs with (blue locktight as well) then conducted a thorough cleaning throughout the entire intake manifold.

BTW...that partial polish job on the upper intake plenum ports was properly finished and done to the lower, I didn't leave it like that. Just wanted to take the pic before I got too involved ;)

Those bolts were only used during the casting process of the aluminum from the factory and serve no purpose so you could have just removed them all like I did. Mine were all still tight besides 2 at around 50k miles, although one was 50% backed out :( so I can imagine what yours were like at 141k miles! Either way, since you torqued them and used locktight they should never be a problem again but for those of you who do this, feel free to remove all 8 bolts and toss them for peace of mind.

[Gosser]

x2 what mistral said.

However, those bolts actually do not pose any harm. They are long enough that they cannot completely back out. There is a thread somewhere that illustrates the interference before they can become free.

But remove them for peace of mind, or lock tight them in.

[brianup]

my b6 s4 always had a little chain slap during cold start but never during warm start. then after a day of spirited driving i started getting warm rattle and the rattle lasted much longer (4-5 seconds vs. 1/2 second). Had my check valved replaced this weekend and boom barely any rattle.

credit this thread for the diagnosis and resolution. i think this is a very nice find and should be on the short list of things you should do on all 100k+ cars or any car that has a excessive rattle at warm or cold startup...

VERY HAPPY!!

[p3u]

Glad to see this thread is going strong and helping out so many people!

[SquiddyB6S4]

Continuing the off topic:
For what it's worth, I thought Audi's intake manifolds were magnesium, not aluminum, because cast aluminum was too weak to be formed and reliable in such thin castings. Big difference between the two, especially with magnesium's added flammability when it comes to the shavings you might create when extracting stripped screws or cutting or shaving the halves apart, using abrasives to do port work, etc.

[EvoRam]

Glad to see this thread is going strong and helping out so many people!

I need to finally do mine this winter on my next oil change.

[EvoRam]

I need to finally do mine this winter on my next oil change.

So...I went ahead and stopped by my old work and finally ordered up all the parts to do this! Boom! I still need to order up JHM intake mani spacers too.

[jpulll]

Has anyone put thought into thinking this check valve could possibly fail in the 1.8t oil filter housing?I am having chain rattle/adjuster noise 2-3 seconds upon startup and have reason to suspect this valve is the reason. Instead of having 2 valves like the V6 and V8 this one would have 1 valve...makes sense right haha. Im hoping if i get to this job that it will be open and i can shed some light for some other people having this problem during engine startup. I completely understand that this valve replacement is only a bandaid because I'm sure some wear has occurred with the chain tensioner or adjusters.

[Smokn337]

I don't know if the 1.8T even has this check valve. This particular chain rattle seems to be exclusive to the 4.2L V8 in the S4s. I could be wrong though. The 1.8T problems all seem to be the tensioners which are much easier to service than on the 4.2L engine which requires an engine removal. On the 1.8T, the rattle occurs most often a few seconds after start up and seem to keep rattling. The 4.2s it is for a few seconds as you start and goes away for most.

[jpulll]

I have diagrams of the oil filter housing and it is there. Has 4 propellers on it just like the s4 guys. Well after more research I have reason to believe it is the cam chain adjuster. But I still for some reason think it is that valve because my car only rattles for the first few seconds on startup, like the s4 guys, and then once it gets oil pressure it's golden...

[EvoRam]

Ordered up JHM intake spacer kit today in preperation for this job.

[EvoRam]

Did the install today with my Audi tech friend at his place. Original valves appeared to be functional. Initial startup after install had slight rattle, then a few starts after were quiet. Had one rattle when warm. I will update with more info over the next days and week(s) I installed JHM spacers while I was in there and also replaced my PCV and suction jet pump too.

Here are some pics. (I cleaned up as you can see, but didnt go too crazy).

Before


After


Valves all looked pretty clean

[m-ys4]

ordered my check valve kit today, looking forward to getting this rattle fixed!

[m-ys4]

Every warm or cold start I'd get the horrible rattle. Now 100% gone!

this was what i was looking for! i have the repair kit with new gaskets valves etc... first thing tomorrow this is getting done i cannot wait! now in Toronto we have finally gotten winter, the last two cold starts have been awful, made my stomach hurt lol. cant wait to report about my cold start/warm being gone!

[m-ys4]

You can add me to the list of "rattle gone"... I don't have a cold start rattle or warm anymore!

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[dolphin B6 S4]

You can add me to the list of "rattle gone"... I don't have a cold start rattle or warm anymore!

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This thread still needs to be stickied!

[mistral cytz]

You can add me to the list of "rattle gone"... I don't have a cold start rattle or warm anymore!

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Hopefully it doesn't come right back again after a few weeks like my car.. If it does you'll want to join the Toronto S4 start up rattle support group. It's all my buddies with S4s local in toronto have been talking about since this cold snap hit us.. 👎

[m-ys4]

Are you guys still looking for a solution to ditch the rattle?

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[m-ys4]

Ugh so this morning I started it and there was a slight rattle, I shut it off and turned it on again, it didn't do it that time... there's no way a brand new valve can be ceased.. could it be my tensioner that's bad?

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[EvoRam]

Ugh so this morning I started it and there was a slight rattle, I shut it off and turned it on again, it didn't do it that time... there's no way a brand new valve can be ceased.. could it be my tensioner that's bad?

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You have to remember this is not a fix-all, but a temp solution and cheap insurance to try to eliminate as much rattle as possible. Remember that 'startup rattle' is "normal" per Audi on these motors.

[SprintBlueWorld]

^^+1

There are mixed results with this procedure. Going back to the OP did find and replace a stuck check valve resolving the rattle and saving parts from undue startup wear and tear. There are additional benefits to this service cleaning up dirt gaining familiarity with your motor adding intake spacers refreshing with new parts etc.

[m-ys4]

I see... I guess ill have to see what happens, hoping its just a winter thing, I was thinking about a block heater, if the motor stayed somewhat warm could this completely eliminate the rattle at cold start? Since it doesn't happen when warm

[EvoRam]

I see... I guess ill have to see what happens, hoping its just a winter thing, I was thinking about a block heater, if the motor stayed somewhat warm could this completely eliminate the rattle at cold start? Since it doesn't happen when warm

Really just depends. I doubt it would stay warm enough, but you could try it out. What oil/weight are you running during the winter?

[m-ys4]

I don't drive too much, Im due for an oil change probably in about 2000km, haven't changed it since October. I put oem 5w40 from the dealer.

[EvoRam]

Try the OE C5 RS6 5w40 Castrol or Mobil 0w40. Do some research first, but maybe try them out.


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[jr1415us]

I see... I guess ill have to see what happens, hoping its just a winter thing, I was thinking about a block heater, if the motor stayed somewhat warm could this completely eliminate the rattle at cold start? Since it doesn't happen when warm

Not strictly temp related. When the car is warm there's residual oil under pressure in the chain tensioners, and also sticking to the timing components. When the car is cold that usually means it's been sitting overnight or longer, and the oil pressure in the chain tensioners has bled down.

[m-ys4]

a lot of guys are saying 0w30 for winter and 5w40 for summer... what do you think is best?

[SprintBlueWorld]

a lot of guys are saying 0w30 for winter and 5w40 for summer... what do you think is best?

The Great Oil debate has been covered in uncounted innumerable posts, and will continue on and on. It shouldn't be done in this thread tho.

[EvoRam]

a lot of guys are saying 0w30 for winter and 5w40 for summer... what do you think is best?

One of my Audi tech buddies said to use the factory fill RS6 5W40 oil in the winter and the factory fill R8 60 weight oil in the summer.


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