Anyone ever thought of swapping out the thermostat on these cars? The damn engines run SO hot, I would think this would do nothing but help performance and assist in the ever-occuring 4.2 oil sipping engines. Any ideas? beinefficientits/downsides? Anyone make a kit? Im sure that JHM does NOT make a new thermostat for a good reason. What is it?
last time this was brought up I recall JHM’s calibrator being concerned about how the ecu would react to the motor running cooler.
That is a good point, I believe this car has a electronic controlled thermostat so it probably cant just be replaced like other cars. Perhaps it is possible to tune the temperature down? I know on the RS4 there was a flash that raised the oil temp, so why not make a flash to slightly lower it.
he said it was, but given the volume of other projects and the number of systems that would need to be adjusted accordingly it would be a while before it could happen.
Hopefully he’ll have a chance to chime in here.
I can only speak of past experiences. Back in the day that would be the FIRST thing we did. Swap out the stat and re tune the car.
The widespread knowledge of the 4.2’s consuming oil has been attributed to super high temps. Seems like a stat swap is the easiest way to get them down. Get on it JHM!
Just read, this may work on the S4, but on the RS4, according to the engine study guide, “The 4.2L V8 FSI engine in the RS4 does not use the map controlled thermostat as found in the Audi Q7 engine.”
Maybe it would be possible to replace it with another thermostat, would probably have to be custom made.
In the ETKA parts diagram, the thermostat looks like a regular mechanical one in any car. Catless+tune+intake spacers are a good way to keep motor/cylinder temps down
Those mods help keep the cylinder temps down by lowering intake and exhaust temps, but these guys are talking about actually trying to lower the coolant temp significantly which would help with oil temps, and be good for the motor.
It may be possible to do, but like beemercer suggested, it will likely cause the tune to freak out and at the least set a code for faulty thermostat (a code I know all too well on my BMW). Perhaps it is possible to code all that out in the tune though?
@JOE
I am already running catless with the JHM93 tune, only thing left now to do is the intake spacers. My car (90,000k young) still sucks down way too much oil imo. I have had junker cars that ive gone 4,000miles between oil changes without a drop missing. Sure the oil may have been dirty, but at least it was all there!
The stat question is basically a final attempt at lowering temps and trying to keep a bit more oil intact without have to “top off” quite as often. Would def be interesting to hear if someone has already done this on a B6/B7 S4 platform.
Sure Ill beat most guys on the road in a race, but I doubt the majority of dd’s have to carry oil in their trunk :-[
Well you don’t really know that the oil is burning off because of high temps. There is likely some getting past the rings, but these cars have also been known to leak it through the valve seals, both main seals, valve cover gaskets, and they also take a heavy dosage of oil through the PCV system-new valve or not.
It say anything around 1L/3-4k miles is normal and healthy
How much oil are you burning between oil changes and how often do you change your oil?
I posted a thread about 4.2 oil consumption a while back. I know it is somewhere within this forum. I was told a few things to combat the issue:
- go catless
- replace pcv
- change from mobile1 to liqui moly (5w-30)
- pray it’s not scored cylinder walls
I have done all of these and still see major oil consumption. If i was burning 1quart every 3k-4k I would never say a word. My car burns SIGNIFICANTLY more than that. I am talking about 2 quarts every 500 miles or so. When I drive more spirited obviously it seems to burn more. I love the car, but this honestly may force me to sell it. Even a quart every 3k-4k miles is absurd. Nobody (including AudiofAmerica) can tell me that it is “normal” for a car to burn some oil. Cars burn gas not oil, but thanks AoA.
I have kept a log (before and after the mods see above) as far as oil top-offs, their increments, and the mileages driven and I didn’t see too much of difference from the before and after logs.
Keep in mind, the car pulls like a train, shifts and drives great, and there are really NO issues with it (except of course for a broken golvebox hinge). All of this brings me back to why I asked about a thermostat mod for the car. I love the car, but WTF i spend more on oil than gas almost! The car isn’t my dd so I can deal with it, but the consumption is WAY excessive imo. Any feedback? Is it time to part with her?
Sorry totally forgot to answer your questions from your previous post.
-My oil gets changed every 4,000 miles or twice a year (april 1st and oct 1st). Oil is LiquiMoly 5w30 as recommended by JHM and elsewhere.
-top offs between changes vary depending on how the car is being driven. According to my logs I put about 2 quarts in as a top off for every 500 miles driven. This seems to be the average.
The annoying thing here is that I don’t really EVER need an oil change because I am constantly cycling new oil through the engine due to all the top offs.
I feel like if I had scored cylinder walls or a seriously major problem the car would drive significantly different but she rides great. FYI the valve cover gaskets have about 35k miles on em and I don’t really ever see oil oozing from there when I look.
Thanks for any input!
that’s absolutely nuts.
TTSIAMABAGT3
At that rate of consumption you have an issue. I’m guessing a scored cylinder wall, worn rings, broken ring or extremely worn valve seals. Maybe an egged piston/piston skirt. That’s huge consumption.
First off, who on earth recommend that oil? that is NOT the oil you should be using. Switch back to Mobil 1 0w-40 or run Motul 8100 x-cess 5w-40. The LubroMoly shit is massively overrated and over priced.
500 miles to a quart is a big issue and really, I don’t think changing oil or lowing engine temps are going to change a thing. You either have a bad PCV that is just siphoning oil into the motor, sever valve stem leaks, or…are you sitting down?..scored cylinders.
<------Worst comes to worst, follow the arrow to the left.
Nice job lining up the arrow 
too bad I already said that joe. You’re slowing down!
well played!
Pretty upsetting, my heart just sank in my chest a bit. Jhm actually rec’d the oil and I have been buying that off of their site.
As mentioned before, the PCV has less than 5,000 miles on it and the old one that was removed from the car was clean as a whistle.
Wouldn’t severe valve stem leaks or more so scored cylinders make a noticeable difference in performance?
Are there any tests I can run to eliminate some of these potentially horrid possibilities?
Are there any fixes short of a new short block? Fuck me